ML031490466

Accepted Version of Topical Report No. 24370-TR-C-001-A, Alternative Rebar Splice -Bar-Lock Mechanical Splices

ML031490466
Person / Time
Site:	Sequoyah
Issue date:	05/19/2003
From:	Salas P Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
24370-TR-C-001-A, TAC MB5271
Download: ML031490466 (134)

Text

Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 May 19, 2003 U.S. Nuclear Regulatory Commission ATTN:

Document Control Desk Washington, D. C. 20555 Gentlemen:

In the Matter of

)

Docket No.

50-327 Tennessee Valley Authority SEQUOYAH NUCLEAR PLANT -

ACCEPTED VERSION OF TOPICAL REPORT NO. 24370-TR-C-001-A, "ALTERNATE REBAR SPLICE -

BAR-LOCK MECHANICAL SPLICES"

Reference:

NRC letter to TVA dated March 13, 2003, Safety Evaluation of Topical Report No. 24370-TR-C-001, "Alternate Rebar Splice -

Bar-Lock Mechanical Splices" (TAC NO. MB5371)

The purpose of this submittal is to provide the accepted version of the subject topical report as requested in the reference letter.

The accepted topical report now includes a copy of the reference letter, historical review information, and any original report pages that were replaced.

The "-A" has been included in the topical report number to designate NRC acceptance.

There are no commitments contained in this letter.

This letter is being sent in accordance with NRC RIS 2001-05.

If you have any questions about this change, please telephone me at (423) 843-7170 or J. D. Smith at (423) 843-6672.

las sing and Industry Affairs Manager Enclosure PNled ye recycled paper

030428 QA Record I

I APPROVED This pproval does nol raines the Conrtsctor trom any prt of hl r-mponlbllfty lot the correctnss of eosign.

• tails and drnenslona.

Letter No. TVBEC-0393 Dat Api 28, 2002 VALLEY AUTHORITY BY P.O. Tsudet TEUISall to'P (N)

A, ALTERNATE REBAR SPLICE BAR-LOCK MECHANICAL SPLICES TOPICAL REPORT PROJECT Sequoyah DISCIPLINE N

CONTRACT 99N5B-253631 UNIT I

DESC. Topical Report - Mechanical Rebar Coupler Qual.

DWG/DOC NO.

24370-TR-C-001-A SHEET OF REV.

00 DATE 04/28/03 ECNIDCN FILE N2N-059 0

2120/02 Issued for TVA use SWK DlK JVS REV.

DATE REASON FOR REVISION BY EGS PE JOB NO.: 24370

. DOCUMENT NO.:

24370-TR-C-001-A RIMS, WTC A-K B 88 8 08

SEQUOYAH UNIT 1 STEAM GENERATOR REPLACEMENT ALTERNATE REBAR SPLICE -

BAR-LOCK MECHANICAL SPLICES TOPICAL REPORT r

Topical Report 24370-TR-C-001-A Table of Contents NRC Acceptance Letter and Safety Evaluation Report for Topical Report 24370-TR-C-001, "Alternate Rebar Splice - Bar-Lock Mechanical Splices".......................................... 3a-3g 1.0 Abstract..........

4 2.0 Introduction..........

4 3.0 Objectives........

4 4.0 Regulatory Requirements/Criteria for Mechanical Splices...........................................

5 4.1 NRC Regulatory Guide 1.136, Materials, Construction, and Testing of Concrete Containments............................................................

5 4.2 ASME Section III, Division 2, Paragraph CC-4333, Mechanical Splices.......................... 5 4.3 ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products.............................................................

6 4.4 ANSI N45.2.5, Supplementary Quality Assurance Requirements for Installation, Inspection, and Testing of Structural Concrete and Structural Steel During the Construction Phase of Nuclear Power Plants............................................................

7 5.0 Description of Bar-Lock Couplers............................................................

7 6.0 Criteria for Qualification Testing...........................................................

10 6.1 Code of Record..........

10 6.2 10CFR50 Appendix B Elements.......................

10 6.3 QA Programs......................

11 6.3.1 Consolidated Power Supply.11 6.3.2 Bar-Lock.11 6.3.3 Idaho National Engineering and Environmental Laboratory (INEEL).12 7.0 Previous Commercial Bar-Lock Testing Information........................................

12 7.1 Summary of Previous Tests.........................................

12 7.2 Conclusions.........................................

13 8.0 Bechtel/INEEL Testing Program.........................................

13 8.1 Overview........................................

13 8.2 Test Plan........................................

14 8.3 Mechanical Properties Test Results for Reinforcing Bar.........................................

14 8.4 Description of Coupler Test Specimens.........................................

16 8.5 Test Results.........................................

16 8.5.1 Tensile Test Results.17 8.5.2 Cyclic Test Results.19 8.5.3 Coupler Test Program Conclusions.20 9.0 Sequoyah Bar-Lock Installation........................

21 9.1 Splicing Crew Qualification........................

21 9.2 Inspection Criteria........................

21 9.3 Production/Sister Splice Testing........................

21 9.4 Acceptance Criteria........................

22 9.5 Quality Assurance/Quality Control........................

23 10.0 References........................

23 Appendices A

Strength Tests of S-Series Bar-Lock (MBT) Coupler for Bar-Lock (MBT) Coupler Systems, Inc.24 B

Cyclic Tests of S-Series Bar-Lock Couplers for Bar-Lock (MBT) Coupler Systems, Inc. 37 C

Cyclic Tests of L-Series Bar-Lock (MBT) Couplers for Bar-Lock (MBT) Coupler Systems, Inc.............................................................

48 D

ICBO ES Cyclic Tests on L-Series MBT Couplers for Bar-Lock Coupler Systems......... 56 Page 2 of 88

Topical Report 24370-TR-C-001-A E

Tabulated Mechanical Test Results and Example Raw Data Bechtel/INEEL Tests....... 77 F

No Significant Hazards Consideration Determination.................................................... 85 G

Responses to NRC Request for Additional Information................

...................... 88a-88ak Tables 8-1 Mechanical Properties of Rebar Used in Test Specimens............................................ 15 8-2 Bar-Lock L-Series Coupler Specifications (Sizes #6 and #8)......................................... 16 Figures 5-1 Bar-Lock Coupler Cutaway.............................................

8 5-2 Bar-Lock Coupler Installation.............................................

9 Page 3 of 88

Topical Report 24370-TR-C-O1-A NRC Acceptance Letter and Safety Evaluation Report for Topical Report 24370-TR-C-001, "Alternate Rebar Splice - Bar-Lock Mechanical Splices" r

Page 3a of 88

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001

• • 4c March 13, 2003 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNIT 1, SAFETY EVALUATION OF TOPICAL REPORT NO. 24370-TR--C-001, ALTERNATE REBAR SPLICE - BAR-LOCK MECHANICAL SPLICES" (TAC NO. MB5371)

Dear Mr. Scalice:

On March 18, 2002, the Tennessee Valley Authority (TVA, the licensee) submitted Westinghouse Topical Report No. 24370-TR-C-001, Alternate Rebar Splice - Bar-Lock Mechanical Splices" to the staff, supplemented by a letter dated December 10, 2002.

The staff has reviewed Topical Report No. 24370-TR-C-001, "Altemate Rebar Splice -

Bar-Lock Mechanical Splices" and found the Topical acceptable. The enclosed Nuclear Regulatory Commission (NRC) safety evaluation contains the staff's determination. However, this acceptance applies only to the Bar-Lock coupler assembly using American Society for Testing Maintenance A615 Grade 60 material in the #6 and #8 sizes for use on non-containment (i.e., shield building) applications at TVA's Sequoyah Units 1 and 2.

In accordance with the guidance provided on the NRC web site, we request that TVA publish an accepted version of this topical report within 3 months of receipt of this letter. The accepted version shall incorporate this letter and the enclosed safety evaluation between the title page and the abstract. It must be well indexed such that information is readily located. Also, it must contain in appendices historical review information, such as questions and accepted responses, and original report pages that were replaced. The accepted version shall include an "-A" (designated accepted) following the report identification symbol.

s GT

If the NRC's criteria or regulations change so that the conclusions in this letter are invalidated, thus making the topical report unacceptable, TVA will be expected to revise and resubmit its respective documentation, or submit justification for the continued applicability of the topical report without revision of the respective documentation.

If you have any questions concerning.this matter, please contact Eva Brown at (301) 4152315.

Sincerely, Raj K. Anand, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-327

Enclosure:

Safety Evaluation cc w/encl: See next page J. A. Scalice _,

t

Mr. J. A. Scalice Tennessee Valley Authority cc:

Mr. Karl W. Singer, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. James E. Maddox, Acting Vice President Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Richard T. Purcell Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Robert J. Adney, General Manager Nuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 SEQUOYAH NUCLEAR PLANT Mr. Pedro Salas, Manager Licensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Mr. D. L. Koehl, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Executive Hamilton County Courthouse Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854 Mr. Mark J. Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 f

UNITED STATES

-f t

NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR SAFETY EVALUATION OF TOPICAL REPORT NO. 24370-TR-C-001.

"ALTERNATE REBAR SPLICE - BAR-LOCK MECHANICAL SPLICES" TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT. UNIT 1 DOCKET NO. 50-327

1.0 INTRODUCTION

In a letter dated March 18, 2002, Tennessee Valley Authority's (TVA, the licensee) Sequoyah Nuclear Plant (SQN) submitted a topical report for an alternate methodology for splicing reinforcing bars in concrete for nuclear safety-related applications at SQN. The topical report proposes that a Bar-Lock coupler system is now available for splicing reinforcing bars.

Presently, the SQN licencing basis does not address the use of this type of reinforcing bar splice. This topical report describes a qualification testing program and test results for the Bar-Lock coupler system. On July 9, 2002, and October 24, 2002, meetings were held between the U.S. Nuclear Regulatory Commission staff (the staff) and TVA. Subsequently, the staff issued a request for additional information dated December 4, 2002. The licensee provided response to the additional information in a letter dated December 10, 2002.

2.0 TEST PROGRAM Bechtel.Corporation and Idaho National Engineering and Environmental Laboratory (INEEL) developed and performed a testing program for the Bar-Lock coupler system to assess its-performance characteristics. TVA was heavily involved in the Bechtel/INEEL test program, and reviewed and approved the specifications, procedures and test plans associated with the procurement, testing, and installation of the Bar-Lock couplers.

VA civil engineers attended the vendor training session. TVA Engineering and Quality Assurance (QA) personnel witnessed the preparation of several test assemblies, and the testing of several spdcimens.

TVA reviewed and approved the testing program and performance analysis, prepated by INEEL.

The reinforcing bar used in the Bar-Lock coupler assembly testing program was American Society for Testing and Maintenance (ASTM) A615 Grade 60 material in #6 and #8 sizes. The mechanical properties for the reinforcing bars were tested in according to ASTM Designation A 370-96, Standard Test Methods and Definitions for Mechanical Testing of Steel Products; and ASTM Designation E 8-99, Standard Test Methods for Tension Testing of Metallic Materials.

Enclosure t -

The component parts of each Bar-Lock coupler consist of a steel tube, "lock-shear" bolts, and serrated rails. The steel tube is seamless hot-rolled in conforming to ASTM A-519, with minimum tensile strength in excess of 100 kilopound per square inch (ksi). The lock-shear bolt

-was made from American Iron and Steel Institute (AISI) 41L40 material, and were through-hardened over the entire length and further induction-hardened at the conical bolt tip. The serrated rails were made of ASTM CD1 018 material, and were machined and then carburized to a depth of 0.032 inch The test specimen assemblies were made by steel construction workers using Bar-Lock's assembly instructions in a normal field environment. Assembly of the test specimens was monitored by Bechtel Quality Control (QC) personnel. The Bar-Lock's assemblies were tested in the same machine that had tested the mechanical properties of the reinforcing bars and in conformance with the same ASTM A 370-96 and E 8-99 standards.

Two reinforcing bar sizes (#6 and #8) of Bar-Lock coupler assemblies were statically tested.

The test was conducted using forty specimens of each of the two sizes of coupler assemblies.

The static test was performed according to the requirements of American Society of Mechanical Engineers (ASME)Section III, Division 2, "Code for Concrete Reactor Vessels and Containment," (the Code) Section CC-4333.2.3(a), Static Tensile Tests for Mechanical Splices.

Forty specimens of each of the two sizes of the Bar-Lock coupler assemblies were tested for cyclic loadings. The cyclic test was performed according to the requirements of ASME Section ll, Division 2, "Code for Concrete Reactor Vessels and Containment," Section CC-4333.2.3(b),

Cyclic Tensile Tests for Mechanical Splices. The Code requires that three specimens of the bar-to-bar splice for each reinforcing bar size shall withstand 100 cycles of stress variation from 5 percent to 90 percent of the specified minimum yield strength of the reinforcing bar. In an effort to improve the cyclic durability assessment, after 100 cycles of loading required by the Code, several specimens were randomly selected to receive an additional 1000 cycles, and several other specimens were statically loaded to failure.

3.0 TECHNICAL EVALUATION

The Code requires six splice specimens for each bar size to be tensile tested statically to failure and three to be tested cyclically. The Code requires that the average tensile strength of the splices shall not be less than 90 percent of the actual tensile strength of the reinforcing bar being tested, nor less than 100 percent of the specified minimum tensile strength. Table CC-4334-1, 'Tensile Requirements for Mechanical Reinforcing bar splices and Welded Joints,"

of the Code lists a minimum yield strength of 60 ksi and minimum tensile strength of 90 ksi for ASTM 615 Grade 60 reinforcing bars.

The INEEL report states that the average tensile strength of the 40 #6 Bar-Lock's assemblies is 106.2 ksi, which is 98.8 percent of the average #6 bar actual tensile strength. The average tensile strength of the 40 #8 Bar-Lock's assemblies is 109.0 ksi, which is 99 percent of the average #8 bar actual tensile strength. None of the 80 specimens tested cyclically failed in any manner (e.g., bar break, or bar slip within the coupler). For those specimens that received additional 1000 cycles of loading, no obvious physical degradation was observed. For those specimens that passed 100 cycles of loading and then statically loaded to tensile failure, the measured tensile strengths were essentially the same as those tested statically to failure without the 100 cycles of loading. The report also states that no practical differences were I

observed in the general character of the stress-strain curve of any of the 80 specimens tested statically, and no measurable slip was detected during the cyclic tests.

The staff finds the QA/QC program for the test specimens adequate. The phenomena of no measurable slip and the similarity in the stress-strain curves of the specimens tested demonstrate that the Bar-Lock's assembly has delivered predictable results and qualifies as a viable reinforcing bar splicing system. The licensee has tested more specimens than that required by the Code, which increases the confidence level for the acceptance of the Bar-Lock's assembly. The static and cyclic test methods and results have met the requirements of the Code. The additional tests of the 1000 cycles of loading and of the tensile test to failure after the 100 cycles of loading exceed the Code requirements.

4.0 CONCLUSION

Based on the information provided by the licensee, the staff determined that the licensee has developed and performed a reasonable test program for the Bar-Lock coupler assemblies, and that the test data demonstrate the adequacy of the proposed alternate methodology for connecting (splicing) reinforcing steel bars for nuclear-safety-related applications at the Sequoyah plant.

Principal Contributor: John Ma, NRR Date:

March 13, 2003 t

Topical Report 24370-TR-C-001-A 1.0 Abstract Original construction of nuclear power plants generally used lap splices or Cadweld splices to join concrete reinforcing steel (rebar). The Cadweld splice became the standard mechanical rebar splice for the nuclear industry, and its use is supported by years of successful installation, industry codes and standards, and regulatory acceptance. However, other mechanical splice technologies, such as the Bar-Lock coupler system, are now available.

The Bar-Lock system has achieved acceptance in.commercial construction, but has not been used in domestic nuclear power applications. Presently, the Sequoyah Nuclear Plant licensing basis does not specifically address the use of this type of reinforcing bar splice. This Topical Report, which details a qualification testing program and test results, has been prepared to support use of the Bar-Lock coupler system as an acceptable alternate mechanical splice for nuclear safety-related applications at the Sequoyah plant.

2.0 Introduction This Topical Report provides a technical justification for the use of Bar-Lock couplers in the restoration of the temporary construction openings in the Sequoyah Unit 1 reactor building as part of the steam generator replacement project (SGRP).

Mechanical splices for reinforcing steel used in nuclear safety-related concrete structures are subject to the stringent requirements of ASME Section 1II, Division 2/ACI-359 and ACI-318, which includes the requirement that the splice develop 125% of the minimum yield strength of the reinforcing bar. In order to demonstrate that the Bar-Lock coupler can meet these requirements, a qualification program has been performed. The qualification program included development of a testing program, performance of physical tests, and analysis and interpretation of the test results.

The Bar-Lock coupler system provides a number of installation advantages over other mechanical splice concepts that make it a candidate for the concrete restoration activities associated with the Sequoyah steam generator replacement. The Bar-Lock coupler system has specified mechanical properties that meet ASME/ACI criteria for mechanical rebar splices. The Bar-Lock coupler has achieved acceptance in commercial construction, including meeting strict Caltrans earthquake requirements.

However, the Bar-Lock coupler has not yet been included (or proposed for inclusion) in NRC guidance for rebar splicing in domestic nuclear power plant applications.

3.0 Objectives The objectives of this report are to present the necessary data supporting the use of Bar-Lock couplers in nuclear safety-related applications at Sequoyah. To achieve these objectives, the following types of information have been compiled:

A description of the couplers is presented in sufficient detail to illustrate the advantages and benefits of this system.

Criteria for the qualification testing of the specific Bar-Lock couplers to be used for the Sequoyah SGRP, including the 10CFR50, Appendix B requirements and a description of quality control of critical processes which were involved in the manufacture and testing of the couplers.

Page 4 of 88

Topical Report 24370-TR-C-001-A A summary of previous commercial testing performed on the Bar-Lock splices.

A description of the Bechtel / Idaho National Engineering and Environmental Laboratory (INEEL) test program and a compilation of the resulting test data, which illustrates the acceptability of the coupler system.

Specifics of the Bar-Lock installation at Sequoyah.

4.0 Regulatory Requirements/Criteria for Mechanical Splices Detailed below are regulatory requirements/criteria that are relevant to mechanical splices.

Following each requirement/criteria is an italicized reference to where the requirement/criteria is addressed within this topical report.

4.1 NRC Regulatory Guide 1.136, Materials, Construction, and Testing of Concrete Containments This regulatory guide states in part that the requirements specified in Article CC-4000 of ASME Section 1II, Division 2, 1980 Edition (also known as ACI 359-80), are acceptable to the NRC staff subject to the following:

Instead of the requirements in subparagraph CC-4333.4.2, splice samples shall be production splices (cut directly from in-place reinforcement.

As discussed in Section 9.3, all splice samples will be sister splices.

4.2 ASME Section III, Division 2, Paragraph CC-4333, Mechanical Splices This section of the ASME Code addresses the requirements for mechanical splices.

Paragraph CC-4333.2.1 requires each splice system manufacturer to conduct a series of performance tests in order to qualify his splice system for use.

The purpose of this topical report is document the perfornance testing perforrned by BechtetINEEL for the Bar-Lock couplers to support nuclear safety-related use of the couplers at the Sequoyah plant.

Paragraph CC4333.2.3 specifies the type and number of performance tests to be performed. The requirements specified are summarized below:

(a) Static Tensile Tests Six splice specimens for each bar size and splice type to be used in construction shall be tensile tested to failure using the loading rate set forth in SA-370. A tensile test on unspliced specimens from the same bar used for the spliced specimens shall be performed to establish actual tensile strength. The average tensile strength of the splices shall not be less than 90% of the actual tensile strength of the reinforcing bar being tested, nor less than 100% of the specified minimum tensile strength. The tensile strength of an individual splice system shall not be less than 125% of the specified minimum yield strength of the spliced bar. Each individual test report on both the spliced and unspliced specimens shall include at least the following information:

(1) tensile strength; Page 5 of 88

Topical Report 24370-TR-C-001-A (2) total elongation; (3) load versus extension curve to the smaller of 2% strain or the strain of 125% of the specified minimum yield strength of the reinforcing bar.

The gage length for each pair of spliced and unspliced specimens shall be the same, and equal to the length of splice sleeve, plus not less than 1 bar diameter nor more than 3 bar diameters at each end.

Section 8.5.1 provides details of the Bar-Lock static tensile testing performed and the results of the testing.

(b) Cyclic Tensile Tests Three specimens of the bar-to-bar splice for each reinforcing bar size and splice type to be used in construction shall be subjected to a low cycle tensile test.

Each specimen shall withstand 100 cycles of stress variation from 5% to 90% of the specified minimum yield strength of the reinforcing bar. One cycle is defined as an increase from the lower load to the higher load and return.

Section 8.5.2 provides details of the Bar-Lock cyclic tensile testing performed and the results of the testing.

Paragraph CC-4333.4 requires that each splicer prepare two qualification splices on the largest size bar to be used. The qualification splices shall be made using reinforcing bar identical to that to be used in the structure. The completed qualification splices shall be tensile tested using the loading rates set forth in SA-370 and the tensile results shall meet those specified in Table CC-4333-1.

Splicing crew qualification is described in Section 9.1.

Paragraph CC-4333.5.3 requires that splice samples be tensile tested.

The schedule for testing of production/sister splices at Sequoyah is described in Section 9.3.

Paragraph CC-4333.5.4 requires that splice samples be tensile tested using the loading rates set forth in SA-370 and meet the following acceptance standards:

(a) The tensile strength of each sample shall equal or exceed 125% of te specified yield strength as shown on Table CC-4333-1.

(b) The average tensile of each group of 15 consecutive samples shall equal or exceed the specified minimum strength as shown in Table CC-4333-1.

The acceptance criteria that will be used for testing of splice samples are described in Section 9.4.

4.3 ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products Section 10 of the standard specifies the requirements for gage marks to determine the percent elongation.

Page 6 of 88

Topical Report 24370-TR-C-001-A A discussion of the determination of the mechanical properties of the rebar used in the coupler testing is provided in Section 8.3. This discussion includes information on the gage lengths used.

Section 13 of the standard specifies acceptable methods for determining tensile properties.

A discussion of the deternination of the mechanical properties of the rebar used in the coupler testing is provided in Section 8.3. The results of the testing of the coupler assemblies are provided in Section 8.5.

4.4 ANSI N45.2.5, Supplementary Quality Assurance Requirements for Installation, Inspection, and Testing of Structural Concrete and Structural Steel During the Construction Phase of Nuclear Power Plants ANSI N45.2.5 specifies supplementary quality assurance requirements for installation, inspection, and testing of structural concrete and structural steel for nuclear power plant construction.

Sections 6.2, 6.3, and 9.5 describe the conforrnance to quality requirements for the Bar-Lock couplers and installation of the couplers at Sequoyah.

5.0 Description of Bar-Lock Couplers Bar-Lock couplers are manufactured of seamless hot-rolled steel tube conforming to ASTM A-519, with a minimum tensile strength exceeding 100 ksi. The couplers utilize a combination of lockshear bolts and heat-treated internal serrated rails to create a mechanical connection that exceeds the ASME and ACI requirements. A cutaway view of a typical Bar-Lock coupler is provided in Figure 5-1. The serrated rails extend the length of the tube to cradle and grip the rebar. As the bolts are tightened, they embed into the rebar. The serrated rails also embed into the rebar and the interior wall of the tube. The number of bolts required is dependent on the size of the rebar to be spliced.

Unlike the 3 bolts shown on Figure 5-1, the Bar-Lock couplers for the #6 and #8 rebar used at Sequoyah utilize 4 and 5 bolts, respectively.

Page 7 of 88

Topical Report 24370-TR-C-001 -A A - Coupler Barrel B - Lockshear Bolts C - Serrated Rails D - Center Pin Figure 5 Bar-Lock Coupler Cutaway Installation of the Bar-Lock coupler is as follows:

Insert the first rebar half way into the coupler to the center pin.

Tighten the bolts to snug (finger-tight) fit.

Insert the second piece of rebar half way into the other end of the coupler to the center pin.

Tighten the remaining bolts to snug fit.

Tighten all bolts in a random alternating pattern, making a minimum of two passes of tightening each bolt prior to shearing the bolt heads.

This installation process is depicted in Figure 5-2.

Page 8 of 88

Topical Report 24370-TR-C-001-A Figure 5 Bar-Lock Coupler Installation The couplers are easy to install, normally requiring no special equipment and minimal operator training, and do not require special rebar preparation. Each coupler uses lockshear bolts that require a specified minimum torque to shear the bolt heads off.

Most coupler sizes can be installed with a standard impact wrench, and smaller sizes require only a manual socket wrench. No heavy crimping equipment or threading devices are required. The couplers can be used when rebar is fixed in a position (positional) as well as when the rebar is free to rotate (standard).

The susceptibility of the Bar-Lock splice bolt tip materials to stress corrosion cracking (SCC) has been considered. For SCC to occur, three elements are required: (1) a susceptible material, (2) a corrosive environment and (3) tensile stress. Higi hardness, low alloy steels are susceptible to stress corrosion under some circumstances.

However, the alkaline environment of properly specified and placed concrete is normally not corrosive to steel. The concrete at Sequoyah is formulated to industry standards and should provide a non-corrosive environment for the reinforcing bar and other steel components. In addition, the bolts in the Bar-Lock splice are tightened against the reinforcing bar so that they are in compression, not tension. Therefore, the three necessary conditions for stress corrosion do not occur in the application of Bar-Lock splice bolt tips at Sequoyah.

Page 9 of 88

Topical Report 24370-TR-C-001-A 6.0 Criteria for Qualification Testing Regulatory requirements/criteria for the use and testing of mechanical splices are detailed in Section 4.

6.1 Code of Record As indicated in Sections 3.8.1.2 and 3.8.3.2 of the Sequoyah UFSAR, the structural design of the shield building and interior concrete structures is in compliance with the American Concrete Institute (ACI) 318-63 building.code working stress design requirements. The reinforcing steel conforms to the requirements of ASTM Designation A 615, Grade 60. Construction was carried out under the requirements of TVA Construction Specification G-2. UFSAR Section 3.8.1.1 states that reinforcing bars were lap spliced in accordance with ACI 318-63 requirements for Strength Design.

6.2 ICFR50 Appendix B Elements I OCFR50, Appendix B establishes quality assurance requirements for the design, construction, and operation of structures, systems, and components (SSCs) that prevent or mitigate the consequences of postulated accidents that could cause undue risk to the health and safety of the public. The pertinent requirements of 10CFR5O, Appendix B apply to activities affecting the safety-related functions of those SSCs. Since the planned use of Bar-Lock couplers at Sequoyah will be to restore the safety-related shield building, 10CFR50, Appendix B requirements are applicable to the design, purchase, fabrication, handling, shipping, storage, inspection, testing, and installation of the couplers. Specifics on conformance to the Appendix B requirements relative to the use of Bar-Lock couplers is provided in the quality assurance manuals, plans, procedures, and specifications described below.

As indicated in Chapter 17 of the Sequoyah UFSAR, design and construction activities at the Sequoyah plant will be in accordance with the latest approved revision of the TVA Nuclear Quality Assurance Plan (TVA-NQA-PLN89-A). Bechtel activities related to the Unit 1 SGRP will be in accordance with the latest revision of the Bechtel Project Nuclear Quality Assurance Manual (PNQAM). INEEL work has been done in accordance with the INEEL Quality Assurance Project Plan. Bechtel witnessed and verified implementation of Bar-Lock's manufacturing quality control processes and procedures for compliance with the applicable provisions of ANSI/ASME N45.2. Reinforcing bar used in testing of the Bar-Lock couplers was procured from Consolidated Power Supply and fabricated by Birmingham Steel Corporation. Activities were performedJn accordance with the QA programs in effect at the time of reinforcing bar fabrication and procurement.

Bechtel specifications issued to purchase, test, and install the reinforcing bar and Bar-Lock couplers that will be used to restore the construction opening in the Unit 1 concrete shield building include:

1. Specification 24370-C-31 1, Technical Specification for Purchase of Bar-Lock Rebar Couplers', Revision 0.

2. Specification 24370-C-303, "Technical Specification for Purchase of Reinforcing Steel", Revision 0.

3. Specification 24370-C-312, "Technical Specification for Installation of Bar-Lock Rebar Splices", Revision 0.

Page 10 of 88

Topical Report 24370-TR-C-001-A

4. Specification 24370-C-601, "Technical Specification for Qualification of Bar-Lock Coupler System for Use in Nuclear Safety-Related Applications", Revision 0.

5. Specification 24370-C-602, Technical Specification for Qualification Testing of Bar-Lock Mechanical Rebar Splices', Revision 2.

6.3 QA Programs 6.3.1 Consolidated Power Supply The reinforcing bar procured for use in the Bar-Lock testing was supplied by Consolidated Power Supply and fabricated by Birmingham Steel Corporation. The supplier's quality assurance program was reviewed by Bechtel and determined to meet the 1 OCFR50, Appendix B requirements. The supplier's QA program conforms to the provisions of ASME/ANSI N45.2, the applicable ANSI N45.2 series standards and Appendix D of Specification 24370-C-303.

The applicable technical, quality, and document submittal requirements were passed on to Birmingham Steel Corporation. Consolidated Power Supply was responsible for the quality of Birmingham Steel Corporation's work and approval of their QA program.

Reinforcing bar used for Bar-Lock coupler testing is identifiable to specific mill heat number(s) and corresponding mill test report(s) through all stages of fabrication. If an identified piece was cut, the original identification was transferred to each piece prior to cutting.

Reinforcing bar used in the test specimens is identifiable from the stage of manufacture through delivery, acceptance, and while in storage. Packaging, shipping and storage of the reinforcing bar was in accordance with ANSI N45.2.2, Level D.

6.3.2 Bar-Lock Bar-Lock couplers are not currently manufactured as nuclear safety-related. Since the Bar-Lock couplers will be used in a nuclear safety-related application, they are subject to a commercial grade dedication program. To support this dedication, Bechtel witnessed and verified implementation of the Bar-Lock manufacturing quality control processes and procedures for compliance with the applicable provisions of ANSI/ASME N45.2. Work performed for Bar-Lock by subcontractors was also subjected to the same procedural, approval and access requirements as the Bar-Lock facility.

The following critical processes and parameters were observed and checked by Bechtel quality personnel at the manufacturing facility to verify implementation of the Bar-Lock quality program and procedures and to ensure the final product met the technical requirements.

Critical Processes Application of material traceability identification on bolt, tube and serrated rail material Tapping of bolt holes Induction heating of bolt tip Fusion of serrated rails to tube Bolt shear test Heat treatment condition of serrated rails Page 11 of 88

Topical Report 24370-TR-C-O1-A Critical Parameters Length of tube Inside diameter of tube Outside diameter of tube Number of bolts Serrated rail location Bolt spacing Bolt edge distance Bolt threads Bolt tip hardness Diameter of bolt shear plane Actual bolt break-point torque values The following records were also examined:

Certified material test reports for tube, bolt and serrated rail material from each heat lot of couplers Bolt tip hardness test results Bolt shear test results Serrated rail heat treatment report Bolt heat treatment report Item packaging and shipping preparation were also examined prior to the first shipment.

6.3.3 Idaho National Engineering and Environmental Laboratory (INEEL)

Work performed by INEEL has been done in accordance with INEEL's Quality Assurance Project Plan and was reviewed by Bechtel and determined to meet the applicable requirements of 10CFR50, Appendix B. The INEEL QA Project Plan conforms to the provisions of ASME/ANSI N45.2, the applicable ANSI N45.2 series standards, and Appendix C of Specification 24370-C-601.

7.0 Previous Commercial Bar-Lock Testing Information Information on previous testing of Bar-Lock couplers is provided in Appendices A, B, C and D of this topical report and is summarized below.

7.1 Summary of Previous Tests As detailed in Appendix A, Wiss, Janney, Elstner (WJE) Associates, Inc. conducted slip tests, tensile strength tests, and compressive strength tests on Bar-Lock S-Series reinforcing bar mechanical couplers. The primary purpose of the tests was to provide data to the International Conference of Building Officials (ICBO) Evaluation Services (ES) for acquiring an evaluation report on the S-Series version of the Bar-Lock coupler.

Secondary purposes of the tests were to compare the static strength performance of the S-Series coupler with the static strength requirements for mechanical connections of reinforcing bars contained in ACI 318-95 and to evaluate slip in the coupler utilizing procedures established in Test 670, promulgated by the Department of Transportation of the State of California (Caltrans). The test results showed that the Bar-Lock S-Series couplers met the ACI 318-95 static tensile and compressive strength requirements for mechanically connected reinforcing bars.

Page 12 of 88

Topical Report 24370-TR-C-001-A As detailed in Appendix B, WJE conducted cyclic tests on S-Series Bar-Lock couplers using a loading protocol established by ICBO ES. This protocol subjected the mechanical connection to 20 elastic cycles below yield, and then 4 inelastic cycles at each of two different strain levels above yield, and then tested the connection to failure under increasing monotonic tension. The test results showed that the Bar-Lock S-Series couplers survived without failure the cyclic ICBO ES testing protocol, and the post-cyclic residual tensile strength of the test specimens exceeded the ACI 318-95 criteria for mechanical connections.

As detailed in Appendix C, WJE conducted tests on L-Series Bar-Lock couplers to evaluate the performance of the couplers after fatigue loading utilizing procedures established by the City of Los Angeles: 100 cycles of tensile load varying from 5% to 90% of the specified yield strength of the reinforcing steel. The couplers passed the cyclic test. The test results also showed that the coupler splices exceed the lesser of either 95% of the average actual ultimate strength or 160% of the specified yield strength of the unspliced reinforcing bar.

As detailed in Appendix D, WJE conducted monotonic compression and reversed-loading cyclic tests on L-Series Bar-Lock couplers in accordance with ICBO ES AC1 33.

The primary purpose of these tests was to provide data to the ICBO ES for acquiring an evaluation report on the L-Series coupler system. A secondary purpose of the tests was to compare the tensile strength performance of the splice with tensile strength requirements for seismic reinforcing bar mechanical splices included in ACI 318-99. The cyclic tensile strengths and monotonic tensile strengths of the Bar-Lock L-Series couplers exceed the minimum strength requirements for a Type 2 seismic mechanical splice according to Chapter 21 of ACI 318-99.

7.2 Conclusions According to the analyses of Wiss, Janney, Elstner Associates, Inc. the previously tested Bar-Lock S-Series and L-Series couplers have successfully met the static and cyclic strength requirements of ACI 318, the ICBO testing protocol, and the City of Los Angeles fatigue loading tests.

8.0 Bechtel/lNEEL Testing Program 8.1 Overview Bechtel Corporation and INEEL developed and performed an independent rpechanical testing and analysis program to assess the mechanical performance characteristics of the Bar-Lock L-Series rebar coupler system. By design, this program provided a very rigorous test of coupler design mechanical performance, using the qualification criteria of ASME Section 1II, Division 2, CC-4333 as a standard of reference.

The Bechtel/INEEL test program tested and demonstrated that the mechanical properties of the L-Series Bar-Lock mechanical splices meet the existing Codes and NRC requirements and are an acceptable method of connecting reinforcing bar in nuclear power plant safety-related applications.

Page 13 of 88

Topical Report 24370-TR-C-001-A 8.2 Test Plan ASME Section CC-4333 specifies performance criteria to qualify rebar splicing devices for use in nuclear safety-related applications. While the strength specifications are moderately high, the quantity of test specimens required is relatively low. To achieve high statistical confidence in measured sample parameters, e.g. ultimate strength, a larger sample size (n) is required. To achieve the desired level of confidence that installation of these couplers will have the requisite performance characteristics, the quantity of verification test specimens (the sample set) was increased. For the static strength assessment, the ASME Code requires 6 specimens be tested, and all 6 must pass. In this test plan, the quantity was increased to n = 40 for each size tested. For the cyclic durability test, the ASME Code requires 3 specimens to survive the 100-cycle test.

This was increased to n = 40 for each size. Increasing the statistical sample size from 6 or 3 to 40 allows a great improvement in the confidence levels (especially for the binomial distribution of the cyclic test) associated with lower bound strength and cyclic durability requirements specified in the Code.

The Bar-Lock testing was monitored by Bechtel QAIQC personnel to ensure that it was performed in accordance with the requirements in Specification 24370-C-602.

8.3 Mechanical Properties Test Results for Reinforcing Bar Mechanical properties for the rebar material used in these tests were determined in accordance with project test procedures, incorporating relevant ASTM test standards and procedures (ASTM A 370 and ASTM E 8). Mechanical properties tests were performed on the same universal test machine, using the same measurement transducers. The same test machine, load cell, and extensometer were used in the coupler assembly tests as well. Representative stress-strain curves for both heats of re-bar are provided in Appendix E, Figures 1 and 2.

The reinforcing bar used in the Bar-Lock coupler testing program was ASTM A615 Grade 60 material in #6 (

4 in. nominal diameter) and #8 (1 in. nominal diameter) sizes.

Consolidated Power Supply, the vendor of the rebar, provided certified material test reports (CMTRs). The values reported in the CMTRs are based on the results of a single tensile test. The CMTR value, while confirming the nominal material performance, is inadequate to determine "actual" material properties. The ASTM test standard recommends a minimum of three specimens be tested and the results averaged.

Additional verification testing was performed as part of this test program to determine the Uactual" or measured mechanical properties of the different heats of rebar erpployed in specimen assembly.

A common heat of rebar (CPS #589812899) was used in making up the #6 size coupler test assemblies. Seven #6 size plain bar sections from this heat were tested to determine actual tensile properties of this lot of material (See Appendix E, Table 1). Per ASME Section II, Division 2 requirements, the same 10 inch extensometer gage length, as was used in the #6 coupler assembly tests, was used to measure strain in the tensile properties tests. The test results are summarized in Table 8-1. Material properties obtained from the Consolidated Power Supply CMTR are provided for comparison.

Table 8-1 illustrates that the differences in yield strength value as determined by three different definitions of yield are minimal. For this type of steel, the yield point is the appropriate measurement and provides the most consistent value (smallest standard Page 14 of 88

Topical Report 24370-TR-C-001-A deviation). Where "measured" or actual" yield strength is required in the analyses, 67.7 ksi is used for the #6L coupler tests. Where measured" or "actual" ultimate tensile strength (UTS, or Fu) is required in the analyses, 107.5 ksi is used for the #6 tests.

Table 8 Mechanical Properties of Rebar Used in Test Specimens Yield Point 0.2%OS 0.5% EUL UTS (ksi) Elongation E (Msi)e (ksi)a Yield (ksi)0 Yield (ksi)c

( )d

1. 6 Average 67.9 68.2 13.2 27.8

1. 6 Std Dev 1.03 1.19 1.14 1.12 1.26 0.89

1. 6 CMTR 67.6 107.4 15

1. 8 Average 72.4 72.5 11.5 29.2

1. 8 Std Dev 0.45 0.57 0.47 0.74 0.98 0.46

1. 8 CMTR 73.1 112.0 14

1. 8 CMTR 69.0 112.8 16 (C-series only)

A common heat of rebar (CPS #589813260) was used in making up the #8 size coupler test assemblies used in the tensile strength tests. Seven #8 size plain bar sections from this heat were tested to determine actual tensile properties of this lot of material (See Appendix E, Table 2). Per ASME requirements, the same 14.5 inch extensometer gage length was used in the tensile properties test as was used in the #8 coupler assembly tests. Test results are summarized in Table 8-1. Material properties obtained from the Consolidated Power Supply CMTR are also provided for comparison. Again, the yield point strength is selected for the material yield strength value. Where measured" or "actual" yield strength is required in the analyses, 72.6 ksi is used for the #8 tests.

Where "measured" or"actual" ultimate strength (UTS) is required in the analyses, 110.1 ksi is used for the #8 tests.

A separate heat of rebar material (CPS #123741) was used to fabricate the #8 size cyclic test coupler assemblies. There are no measured strength parameters (only specified minimums) associated with the cyclic test procedures, so no verification testing of this material was performed. The CMTR-reported values for this heat are provided at the bottom of Table 8-1 for reference.

a The "upper yield point" as observed in most carbon steels.

b Yield strength determined using the offset method.

c EUL = extension under load," the stress at a fixed strain offset from the strain point at the onset of loading.

d CMTR reports elongation based on the standard 8 inches gage length. By test requirements, the gage lengths used in these tests were 10.0 inches for #6 rebar and 14.5 inches for #8 rebar.

There is no requirement or point of comparison in the ASME Code related to the ductility (percent uniform elongation) of the rebar material. It was measured and reported for the plain bar because it is a result of the plain bar test method data analysis of ASTM A370. The measured elongation of the plain bar is not comparable to the elongation measured in the coupler tests.

e Modulus of elasticity in 106 psi.

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Topical Report 24370-TR-C-001-A 8.4 Description of Coupler Test Specimens The Bar-Lock couplers used in the test and to be used at Sequoyah are Bar-Lock's 'L-Series" (coupler designations 6L and 8L), which are higher strength rebar coupler for use in tension/compression, seismic and other cyclic load conditions. The specifications for these couplers are provided in Table 8-2.

Table 8 Bar-Lock L-Series Coupler Specifications (Sizes #6 and #8)

For Coupler Specifications l

Bolt Specifications Coupler Use Nominal Designation Rebar Outside Length Weight Quantity Size Shear Rer Diameter et(inch)

WI per Bar (inch)

Torque size (inch)

(ic)

(lbs.)

(ft-lb.)

6L

1. 6 1.9 8.0 4.5 4

1/2 80 8L

1. 8 2.2 12.3 9.5 5

5/8 180 The component parts of each Bar-Lock coupler consist of a steel tube, 'lockshear" bolts,'

and serrated rails. Figure 5-1 shows a schematic diagram of the coupler design. The seamless, hot-rolled steel tube conforms to ASTM A-519, with a minimum tensile strength in excess of 100 ksi. The lockshear bolt material is AISI 41 L40. The bolts are through-hardened over the entire bolt length and induction-hardened at the conical bolt tip. The serrated rails are made of ASTM CD1018 material. They are machined and then carburized to a depth of 0.032 in.

An equivalent testing program was performed for each of the two coupler/rebar sizes tested. For each size, forty test specimen assemblies were made up for tensile strength tests, and forty assemblies were made up for the cyclic durability tests. The test specimens were assembled by construction craft personnel using Bar-Lock's assembly instructions in a normal field environment. Assembly of the test specimens was monitored by Bechtel QC personnel.

8.5 Test Results The 160 individual coupler specimens tested in this program, and the relevant specimen sample set averages and individual coupler strengths, exceeded the requirements set forth in the ASME Code, Section CC-4333.2.3(a).

t Eighty tensile strength tests (forty of each size) were performed on coupler assembly specimens according to relevant sections of ASTM A 370 and E 8, and ASME CC-4333.2.3(a). A representative stress-strain curve for a coupler strength test is provided in Figure 3 in Appendix E. No practical differences were observed in the general character of the stress-strain curve of the 80 specimens tested. Test data collected included stress, strain, crosshead displacement', applied force, and elapsed time.

f Crosshead displacement refers to the relative separation between the test machine grips - the displacement of the test machine's moving crosshead relative to its fixed one.

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Topical Report 24370-TR-C-001-A The mechanical properties from individual specimen tests, extracted from raw test data using standard analysis methods provided in ASTM E 8, are tabulated in Table 3 in Appendix E. Representative stress-strain plots for a strength test and a cyclic test for each size are provided in Appendix E.

In addition, several specimens of each size were randomly selected to receive an initial slip test prior to the normal strength test. Virgin test specimens were installed in the test machine, and instrumented as for a normal strength test. The applied stress was increased from 0, through 3 ksi, up to 30 ksi, and then reduced to 3 ksi. The change in displacement across the coupler between the two 3 ksi stress levels was measured with an extensometer. Figure 3 in Appendix E shows the traces of applied stress and resultant displacement for the six specimens. In each case, no measurable slip was detected.9 This was expected due to the mechanical interlocking of coupler and bar in the Bar-Lock coupler design. The observation of no bar slip within the coupler on initial loading means the coupler will develop full strength without excessive deformation upon initial loading.

8.5.1 Tensile Test Results The ASME Code, Section CC-4333.2.3, has several criteria with which the coupler performance is compared. The two pertinent criteria for the tensile strength test results are as follows:

1. '...The average tensile strengthh of the splices shall not be less than 90% of the actual tensile strength of the reinforcing bar being tested, nor less than 100% of the specified minimum tensile strength."

As it turns out, the 90% of the actual tensile strength is the goveming criteria. For the size #6 group, the specified minimum average strength value is 96.8 ksi. For the size #8 group, the specified minimum average strength value is 99.1 ksi.

Coupler/bar size #6 The sample set of strength data from the coupler/bar size #6 was evaluated for normal (Gaussian) probability distribution using the Wilk-Shapiro W-test and graphical analysis methods. The results show a near normal distribution, i.e. only slight departure from normality. Where necessary in the assignment of confidence limits, the assumption of normality is justified.

The size #6 group (sample set, n = 40) average tensile strength is 106.2 ksi (98.8%

of the average #6 bar actual tensile strength), with a standard deviation 'of only 1.87 ksi. The Code-required average strength value of 96.8 ksi (90% of actual tensile strength) is 5.0 standard deviations below the sample average. This corresponds to a probability of less than 3 in 10 million couplers would have strength less than the required 96.8 ksi minimum value. Further, a one-sided test for lower bound was also performed. This test provides a practical lower limit strength value for the 6L coupler assembly. Based upon this data set, 99% of the couplers of this 9 The recorded slip displacements, equivalent to less than 0.001 in. over the length of the coupler, were much less than observed hysteresis error in the extensometer.

h This is a single average value, calculated from the entire group (sample set) of replicate test specimens, i.e. from one heat of material, in one size.

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Topical Report 24370-TR-C-001-A type will have a tensile strength greater than 100.13 ksi (with a 99% confidence level). This is a very strong indication that the size #6 coupler design will achieve the required minimum strength.

Coupler/bar size #8 The sample set of strength data from the coupler/bar size #8 was also evaluated for normal (Gaussian) probability distribution using the W-test and graphical analysis methods. Again, results show only slight departure from normality.

The size #8 group (sample set, n = 40) average tensile strength is 109.0 ksi (99.0%

of the average #8 bar actual tensile strength), with a standard deviation of only 2.78 ksi. The required average strength value of 99.1 ksi is 3.6 standard deviations below the sample average. This corresponds to a probability of less than 2 in 10,000 couplers would-have a strength less than the required 99.1 ksi minimum value.

Further, a one-sided test for lower bound based upon this data set indicates that, with 99% confidence, 99% of the couplers of this type will have a tensile strength greater than 99.94 ksi. This is a very strong indication that the size #8 coupler design will achieve the required minimum strength.

To assess the general capabilities of the overall coupler design, the results from both sizes tested can be normalized by their respective bar lot (mill heat) tensile strengths and combined into one sample set. In so doing, the conclusion is that the Bar-Lock coupler design produces a splice that will achieve an average strength that is 98.9%

as strong as the rebar itself. It is obvious that this greatly exceeds the ASME Code-required 90% value. The cumulative standard deviation is 2.2% of the bar strength, making the required minimum strength 4.0 standard deviations below the sample average. The equivalent likelihood is that only 3 in 100,000 would fail to achieve a strength level equivalent to the rebar ultimate strength.

2. "...The tensile strength of an individual splice system (test specimen), shall not be less than 125% of the specified minimum yield strength of the spliced bar."

This requirement for each individual coupler tested provides additional assurance that the occasional sample tested that may have a relatively low strength value, as compared to the sample set average, at least has an absolute minimum necessary strength for structural considerations. For the Grade 60 rebar used in this study, this required value is 75.0 ksi, and is the same for all specimens tested. All specimens tested in this test program passed this test, and by a very large margin.

In the simplest case, the pass/fail criteria can be applied directly. For the combined sample size of 80, with no observed failures (strength below 75.0 ksi), the statement can be made that with 90% confidence, no more than 2.8% of couplers would fail this test. By the nature of this type of binomial probability distribution (pass/fail), it is difficult to state reliabilities with a higher level of confidence until many hundreds of samples are assessed. However, by normalizing the measured individual coupler strengths by the required value, an analysis of the amount of deviation on those values can provide a yet stronger comparison and corresponding statement of reliability.

'This is the strength value of each individual test specimen (coupler assembly) consisting of one coupler unit and two attached sections of rebar.

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Topical Report 24370-TR-C-001-A This distribution of normalized strengths shows that the average coupler strength is 144% of the minimum required level for individual couplers, with a standard deviation of less than 4%. Within this distribution, the probability that the strength of an individual coupler assembly would be lower than the requirement is negligible.

A comment by the NRC during a presentation on the Bar-Lock couplers on August 9, 2001 was that this minimum strength criterion for individual test specimens should be based upon the actual, measured yield strength of the bar material, rather than the specified minimum value as done above. This makes more sense from a practical view, and it removes one variable (the specified material yield strength) from the comparison. This approach does, however, apply a more stringent test of the coupler capability, since the actual yield strength will always be higher than the minimum allowable. To apply this criterion, the size #6 and size #8 specimens must be treated separately since the measured yield strengths of the two bar sizes are significantly different.

Size #6 Couplers Using the appropriately normalized test results from the #6 test specimens, the same analysis described above was carried out. The size #6 coupler specimen tensile strengths averaged 106.2 ksi, 25.4% above the proposed strength level of 84.6 ksi (125%

• 67.7 ksi) with a standard deviation of 1.86 ksi.

Size #8 Couplers Analyzing the normalized test results from the #8 test specimens show their tensile strengths averaged 109.0, 20.1% above the proposed strength level of 90.8 ksi (125%

• 72.6 ksi) with a standard deviation of 2.81 ksi.

The overall strength performance of the Bar-Lock coupler design, can be summarized as excellent, based on this comprehensive test program of different size couplers. There were no failures to meet the specified or proposed strength criteria. As the various failure probability values indicate, the likelihood of an individual Type 6L or 8L coupler assembly failing to achieve the ASME required strength levels is very low.

8.5.2 Cyclic Test Results Coupler assemblies were cyclically tested according to the requirements of ASME CC-4333.2.3(b). Forty specimens of each of the two types (6L and 8L) received 100 load cycles between 5 and 90% of specified minimum bar yield strengti (60 ksi).

None of the specimens failed (e.g. bar break or bar slip) within the coupler.

Applied stress and specimen extension data were digitized during the cyclic tests to provided additional insight into the coupler performance under cyclic load conditions.

Appendix E, Figure 5 shows a representative plot of stress versus displacement. For clarity, only every tenth cycle is presented. It shows the accumulated slip over 100 cycles to be less than 0.0015 in. This is less than 10% of the elastic deformation that occurs during a single load cycle. The same behavior was observed in all of the tests of both coupler sizes. The couplers showed no significant deterioration (visible, or evidenced by deviations in test data) during the tests.

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Topical Report 24370-TR-C-001-A Based on the binomial probability function (pass/fail testing), and no observed failures in 80 tests, it can be stated with 90% confidence that less than 2.8% of the couplers would fail prior to the completion of 100 loading cycles.

Higher Count Cyclic Tests In an effort to improve the cyclic durability performance assessment, several of the specimens in each size were selected at random to receive additional cyclic loading.

Each selected specimen was subjected to an additional 1000 cycles. None of the specimens failed, and none of them showed signs of deterioration through excessive strain accumulation or physical deformation. While this does not provide a verifiable improvement in the statistical probability of failure (the confidence level is too low to be useful), it does provide an engineering indication that the cyclic durability of the couplers will far exceed 100 cycles.

Residual Strength Tests Another test was also performed on randomly selected couplers to provide additional information regarding cyclic durability and residual strength. The selected couplers, each having been subjected to 100 loading cycles, were subsequently loaded to failure monotonically. This is the standard tensile strength test" described in the previous section. The concept here is to determine if the prescribed cyclic loading substantially damages the integrity of the splice assembly. The eight specimens tested achieved the same nominal strength as the corresponding specimens receiving no cyclic loading.

Table 4 in Appendix E summarizes these test results. These observations suggest that cyclic loading in the stress range from 3 to 54 ksi does very little, if anything, to reduce the strength capacity of a spliced joint made using the Bar-Lock L-series coupler.

8.5.3 Coupler Test Program Conclusions The Bar-Lock coupler qualification testing program was carried out on two representative sizes - #6 and #8 - of their L-Series couplers. A total of 160 coupler assemblies were tested. Fourteen pieces of rebar were tested to determine the actual, or measured, mechanical properties of the two heats of bar material used in the test specimens.

The tensile strength tests on 80 samples exceeded the two ASME requirements by a large margin. Statistical analyses of the test results determined several important performance indicators. The overall probability of a coupler assembly (in size #6 or #8) failing to meet the minimum qualification strength criterion is less than 3 in 100,000.

There was some variation in strength between the two heats of rebar used in the strength tests. Comparing and correlating these results show that Bar-Lock L-Series coupler splices can be expected to achieve a tensile strength greater than 96% of the actual bar strength. While there are not enough different combinations of bar material and coupler size data, the combined test results from this program appear similar when normalized by the actual bar strength.

Slip tests performed on selected specimens of both sizes showed a solid mechanical connection between the coupler and the rebar. There was no tendency for the rebar to move within the coupler prior to developing full splice strength. This was expected since the conical-tipped lock bolts physically embed into the bar material providing a physical shear force transfer from bar to coupler.

Page 20 of 88

Topical Report 24370-TR-C-001-A Each of the 80 splice specimens that underwent the cyclic loading durability test passed the 100-cycle test, with no obvious physical degradation of the spliced joint. To provide an additional degree of assurance of adequate cyclic durability, selected specimens received 1000 cycles of loading, again with no noticeable physical degradation. Some of the specimens that passed the 100 cycle test were subsequently tested by monotonic loading to failure. The resultant measured strengths were essentially the same as the virgin strength test specimens (no cyclic loading applied). These results suggest that the design of the Bar-Lock coupler is essentially insensitive to cyclic loading to levels below 90% of the minimum bar yield strength.

The results of these tests, compared to the ASME splice system qualification requirements, indicate that the Bar-Lock coupler design for rebar splicing is entirely adequate from a strength point of view for use in nuclear safety-related construction.

The additional quantity of couplers tested provides higher confidence that the couplers do meet, and indeed far exceed, those ASME-specified requirements.

9.0 Sequoyah Bar-Lock Installation The qualification test results for the #6 and #8 L-Series Bar-Lock couplers demonstrate that, when compared to the ASME splice system qualification requirements, the Bar-Lock coupler design for rebar splicing is more than adequate from a strength point of view for use in nuclear safety-related construction. The additional couplers tested provide higher confidence that the couplers do meet, and indeed far exceed, those ASME-specified requirements. Therefore, use of Bar-Lock couplers for nuclear safety-related applications at the Sequoyah plant is considered acceptable. These #6 and #8 Bar-Lock couplers will be installed at Sequoyah consistent with the process described in Section 5.0.

9.1 Splicing Crew Qualification At least one member of each splicing crew will be trained to install the Bar-Lock coupler.

Splicing crew qualification will be demonstrated by preparing two qualification (test) splices using the largest bar size to be used. On successful inspection and testing of the qualification splices, the crew will be considered as qualified to perform production splices. Each qualified splicing crew shall be assigned an identification mark to be placed on each completed splice. Splicing crew qualification records shall be retained as permanent records.

9.2 Inspection Criteria Inspection of splices shall be in accordance with the manufacturer's instructions and ANSI N45.2.5, except as modified by Specification 24370-C-312. Completed splices will be visually inspected for defects. In addition, it will be verified that bolt heads are either sheared off or torqued to specified values and that the Splicer Crew's identification mark is placed on each splice. Results of splice inspections will be documented and retained as permanent records.

9.3 Production/Sister Splice Testing During the original construction, both rebar production splices and sister splices were used as samples for tensile testing. Sampling of production splices during the Page 21 of 88

Topical Report 24370-TR-C-001-A restoration of the openings created during the SGR would increase the amount of concrete chipback and the potential for reinforcing bar damage. In addition to increased concrete chipback, there would be geometric constraints associated with replacing production splices taken for tensile testing.

ANSI N45.2.5-74 takes exception to taking production splice samples when the splicing sleeve is at a leak tight barrier (embedded structural steel sections or liner plate) and instead requires a representative sister splice sample to be taken.

For the Sequoyah SGRP reinforcing bar splice testing program, a similar approach will be used. Production splices will not be removed for tensile testing and sister splices shall be used exclusively. With the exception of substituting a sister splice for a production splice on a one-to-one basis, the splice tensile testing using this sampling scheme is consistent with the sampling in ANSI N45.2.5-74 when testing both sister and production splices. The proposed testing scheme also substitutes a sister splice for a production splice on a one-to-one basis for handling of substandard tensile test results.

This proposed testing scheme is conservative when compared with the current edition of ASME Section III, Division 2, which requires tensile testing only one splice (sister or production) for every 100 production splices for ferrous filler metal splices.

9.4 Acceptance Criteria Criteria for the acceptability of Bar-Lock splices used during the Sequoyah Unit 1 SGRP are detailed in Specification 24370-C-312 and are summarized below.

1. Sister splices will be tensile-tested using the loading rates set forth in ASTM Specification A-370. Testing will determine conformance to the following standards:

a. The strength of each sample tested shall equal or exceed 125% of the minimum yield strength (i.e. 75,000 psi.)

b. The average strength of 15 consecutive samples shall equal or exceed the minimum ultimate tensile strength (i.e. 90,000 psi.).

2. If any sample splice used for testing fails to meet the above tensile test requirements and the failure occurs in the rebar, any necessary corrective actions will be determined prior to continuing the testing frequency.

If a sample splice used for testing fails to meet the above tensile test requirements and the failure occurs in the splice, two additional sister splices made under the same conditions and in the same position shall be produced. If either of these retests fails to achieve 90,000 psi, splicing shall be halted until the cause of the failures has been evaluated and resolved.

3. If the rate of failure does not exceed 1 in 15 consecutive samples, the sampling procedure shall be started anew.

If the failure rate exceeds 1 in 15 consecutive samples, splicing shall be halted until the cause of the failures has been evaluated and resolved.

4. When splicing is resumed (after being halted for corrective action), the sampling procedure shall be started anew.

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Topical Report 24370-TR-C-001-A 9.5 Quality Assurance/Quality Control Material, installation, inspection and testing of Bar-Lock splices including qualification of installers are classified as safety-related. Safety-related work will comply with Bechtel's Quality Assurance Program for the Sequoyah Nuclear Plant - Unit 1 SGR Project and ANSI N45.2. Qualification of Inspection personnel will comply with ANSI N45.2.6.

10Property "ANSI code" (as page type) with input value "ANSI N45.2.6.</br></br>10" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process..0 References

1.

ASME Boiler and Pressure Vessel Code,Section III, Division 2, Article CC-4333,

'Mechanical Splices", 2001 (ACI 359).

2.

ASME NQA-1, Subpart 2.5, "Quality Assurance Requirements for Installation, Inspection, and Testing of Structural Concrete, Structural Steel, Soils, and Foundations for Nuclear Power Plants", 1997.

3.

ASTM A 370-97a, Standard Test Methods and Definitions for Mechanical Testing of Steel Products".

4.

NRC Regulatory Guide 1.136, Materials, Construction, and Testing of Concrete Containments", Revision 2.

5.

ACI 318-63, Building Code Requirements for Reinforced Concrete".

6.

Tennessee Valley Authority Nuclear Quality Assurance Plant TVA-NQA-PLN89-A, Revision 10.

7.

Bechtel Sequoyah Nuclear Power Plant Project Nuclear Quality Assurance Manual (PNQAM), Revision 1.

8.

Test Program Plan for Qualification of Bar-Lock Coupler System For Use In Nuclear Safety-Related Applications, Idaho National Engineering and Environmental Laboratory.

9.

TVA Construction Specification G-2, TVA General Engineering Specification -

Plain and Reinforced Concrete.

10.

Sequoyah Updated Final Safety Analysis Report, Amendment 16.

11.

ASTM A 615, Standard Specification for Deformed and Plain Billet-Steel Bars for Reinforced Concrete.

12.

1 OCFR50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.

13.

Bechtel Specification 24370-C-311, Technical Specification for Purchase of Bar-Lock Rebar Couplers, Revision 0.

14.

Bechtel Specification 24370-C-303, Technical Specification for Purchase of Reinforcing Steel, Revision 0.

15.

Bechtel Specification 24370-C-312, Technical Specification for Installation of Bar-Lock Rebar Splices, Revision 0.

r

16.

Bechtel Specification 24370-C-601, Technical Specification for Qualification of Bar-Lock Coupler System for Use in Nuclear Safety-Related Applications, Revision 0.

17.

Bechtel Specification 24370-C-602, Technical Specification for Qualification Testing of Bar-Lock Mechanical Rebar Splices, Revision 2.

18.

INEEL Quality Assurance Project Plan for Qualification of Bar-Lock Coupler System for Use in Nuclear Safety-Related Applications, Bechtel Document Number 24370-INEEL-002.

19.

Bar-Lock/ Valley Machining Quality Procedures, Bechtel Document Number 24370-BAR-001.

20.

Consolidated Power Corporation, Supplier Quality Program Evaluation Report, Bechtel Document Number 24370-SQP-2001-001.

21.

ASTM E 8, Standard Test Methods for Tension Testing of Metallic Materials.

Page 23 of 88

Topical Report 24370-TR-C-001 -A Appendix A Strength Tests of S-Series Bar-Lock (MBT) Coupler for Bar-Lock (MBT) Coupler Systems, Inc.

WJE No. 952595 May 24,1996 Page 24 of 88

STRENGTH TESTS OF S-SERIES BAR-LOCK (MBT) COUPLER FOR BAR-LOCK (MBT) COUPLER SYSTEMS. INC WJE No. 952595 May 24, 1996

.4-Wiss, Janney, Elstner Associates, Inc.

29 North Wacker Drive, Suite 555 Chicago, Illinois 60606 (312) 372-0555

Wiss, Janney, Elstner Associates, Inc.

STRENGTH TESTS OF S-SERIES BAR-LOCK (MBT) COUPLER FOR BAR-LOCK (MBT) COUPLER SYSTEMS, INC.

WJE No. 952595 May 24, 1996 INTRODUCTION Wiss, Janney, Elstner Associates, Inc. (WJE), has conducted a series of tests on reinforcing bar mechanical connectors for Bar-Lock (MBT) Coupler Systems, Inc. WIJE tested the S-Series coupler, the shorter version of the Bar-Lock (MBT) coupler, in bar size Nos. 4 through 11, 14 and 18. Tests on all specimens included slip tests, tensile strength tests, and compressive strength tests.

The primary purpose of the tests reported herein is to provide data to ICBO Evaluation Service, Inc. (ICBO ES), for acquiring an ICBO ES Evaluation Report on the S-Series version of the Bar-Lock (MBT)

Coupler. Secondary purposes of the tests are: to compare the static strength performance of the S-Series Bar-Lock (MBT) Coupler with the static strength requirements for mechanical connections of reinforcing bars contained in Building Code Requirements for Reinforced Concrete (ACI 328-95), promulgated by the American Concrete Institute (ACI); and to evaluate slip in the coupler utilizing procedures established in Test 670, promulgated by the Department of Transportation of the State of California (Caltrans).

Unspliced control bar specimens of size Nos. 4 through 11, 14 and 18 were also tested. The control bars came from the same lots of bars as used in fabrication of the connector specimens. The control bar tests were performed to determine the yield strength and tensile strength of the unspliced reinforcing bar. The results of the control bar-tests were compared to the requirements of the "Standard Specification for Deformed axyd Plain Billet-Steel Bars for Concrete Reinforcement," ASTM Designation A615-94.

1

Wiss, Janney, Elstner Associates, Inc.

SPECIMEN ASSEMBLY AND TEST PROCEDURES Nine S-Series couplers each for bar size Nos. 4 through 11, 14 and 18 were provided to WJE by Bar-Lock. Three couplers of each bar size were tested for slip and then tested under monotonic tension loading to failure, and three specimens were tested under monotoric compression loading.

The remaining three specimens were held as spare specimens.

Mechanical Connection Identification. The mechanical splice is comprised of one S-Series Bar-Lock coupler sleeve, which is used to connect two pieces of ASIM A615 reinforcing bar. Key physical data that have been specified for the S-Series couplers by Bar Lock are summarized in Table 1.

At least one representative S-Series Bar-Lock coupler in each bar size was compared to the appropriate Bar-Lock (MBT) Coupler System's standard drawing. WJE made comparisons utilizing drawing Nos. SID-COU-001 through SID-COU-011, dated January 2,1996. The devices tested have the same general appearance as the devices represented by the drawings. Selected measured dimensions agreed with the dimensions indicated on the standard drawings within a tolerance of 1/16 inch. During this test program, Bar-Lock revised the design of the No. 9 S-Series coupler to be the same as that of the No. 10 S-Series coupler, so that the same device would serve to couple either No. 9 or No. 10 bars. The No. 9 coupler reported herein is the revised design coupler. Bar-Lock indicated that the next revision of the standard drawings would indicate that the same coupler is used for both size Nos. 9 and 10.

Splice Assembly Procedure. Each coupler test specimen consisted of two lengths of reinforcing bar connected by the applicable size coupler. Specimens were assembled in the WJE test laboratory by Bar-Lock personnel, or by WJE personnel in accordance with written installation instructions provided by Bar-Lock.

Reinforcing.Bar Sources. The reinforcing bar used in fabricating the specimens were supplied by Bar-Lock. Based on mill crtification reports, the bars conform to ASTM A615, Grade 60, deformed reinforcing bar. The bar for each size tested was obtained from a single source. Mill certificates for the reinforcing bar used in fabricating the test specimens may be found in Appendix A.

_.-?

2)

Wiss, Janney, Elstner Associates, Inc.

Testing Procedures for Monotonically Loaded Specimens. All tension test coupler specimens, compression test coupler specimens, and unspliced reinforcing bar specimens were tested monotonically in axial tension or compression in accordance with "Standard Test Methods and Definitions for Mechanical Testing of Steel Products," ASITM A 370. All tests were directed by a licensed professional engineer who is a WJE staff member.

Monotonic tension tests on couplers, monotonic compression tests on couplers, and monotonic tension tests on unspliced control bar specimens utilized test machines as follows: specimens of size Nos.

4 through 7 were tested in a Satec universal test machine having a capacity of 120,000 lbs, and specimens of size Nos. 8 through 14 were tested in a Riehle universal test machine having a capacity of 500,000 lbs.

Calibration documents for the test machines are found in Appendix B.

Elongation of tension coupler and each unspliced bar control test specimen was measured by a pair of LVDTs installed in a frame having an adjustable gage length. The electrical signal output from the LVDTs and an electrical signal indication of the test machine load were simultaneously monitored by an X-Y chart recorder, which provided force-elongation plots for all tension test specimens. Gage length of the LVDT test frame for the tension coupler tests was as follows: 8.0 in. for size Nos. 4, 5 and 6; 12.0 in. for size Nos. 7, 8, 9,10 and 11; 24.0 in. for size No. 14, and 36.0 in. for size No. 18. Gage length for all control bar tests was 8.0 in., except for the No. 18 control bars, which utilized a clip-on extensometer with a gage length of 2.0 in.

Shortening of all compression coupler test specimens was obtained by using an LVDT that monitored test machine crosshead movement. Crosshead movement was taken to dinectly represent shortening of compression specimens because the projection of reinforcing bar beyond the ends of the coupler was elatively -short. Approximate gage lengths between test machine crossheads at zero compressive load was 5.0,5.8,.5, 9.5, 10.0, 11.0, 12.0, 13.8, 20.5 and 36.0 in. for specimens of size Nos. 4, 5, 6, 7, 8, 9, 10, 11, 14 and 18, respectively. The electrical signal output from the LVDT and an electrical signal indication of the test machine load were simultaneously monitored by an X-Y chart recorder, which provided force-deformation plots for all compression test specimens.

3

/

Wiss, Janney, Elstner Associates, Inc.

Procedures for Measuring Slip.

As part of the monotonic tension test to failure, a slip measurement was made for each coupler specimen. The slip measurements were made with the frame-mounted LVDTs described previously, utilizing procedures established by California Department of Transportation (Caltrans) in California Test 670, "Method of Testfor SteelReinforcingBar Mechanical Butt Splices," revised December 1995. The slip test procedure of C-alifornia Test 670 may be summarized as follows. After the test specimen is installed in the test machine, but prior to application of any significant load, a reading of the LVDTs is taken. Tensile load is then applied so as to generate a nominal stress of 30 ksi in the test specimen. Next, the tensile load is decreased so as to reduce the nominal stress to 3 ksi, and a second reading of the LVDTs is taken. Slip is calculated as the difference between the second LVDT reading (at 3 ksi) and first LVDT reading (at zero load).

TEST RESULTS Couplers Tested in Tension. Results of static tensile strength tests on S-Series Bar-Lock (MBT) couplers are summarized in Table 2. A force-elongation plot was recorded for each test; the plots are presented in Appendix C. Failure modes are also noted in Table 2. Slip measurements, made according to the slip procedures of California Test 670, are also summarized in Table 2.

ACI 318-95 gives static strength criteria for mechanical connections in reinforcing bars.

Section 1214.3 requires that "A full mechanical connection shall develop in tension or compression, as required, at least 125 percent of specified yield strengthfy of the bar." The force corresponding to this ACI strength requirement for a coupler in each bar size is also summarized in Table 2, and was calculated as 1.25-(A,-fy), where A, is the nominal bar area, as tabulated in ASTM A615, and fy is tie specified bar yield strength, taken to be 60,000 psi. The static tensile strength of all couplers summarized in Table 2 met the ACI requirement for a full mechanical connection in tension.

4 4:

Wiss, Janney, Elstner Associates, Inc.

Couplers Tested in Compression. Results of static compressive strength tests on S-Series Bar-Lock (MBT) couplers are summarized in Table 3. A load-deformation plot was recorded for each test; the plots are presented in Appendix D.

To avert the danger of a failure of a specimen due to compression buckling or compression instability, testing of compression specimens was generally halted at a load corresponding to a nominal compressive stress of approximately 90,000 psi (150 percent of specified bar yield strength, fr).

ACI 318-95 gives the same static strength criteria for mechanical connection in compression as it does for a mechanical connection in tension, namely, 125 percent of specified yield strength, f, of the bar. The force corresponding to this AC strength requirement for a coupler in each bar size is also summarized in Table 3, and was calculated as described previously for couplers in tension.

The static compressive strength of all couplers summarized in Table 3 met the ACI requirement for a full mechanical connection in compression.

Control Bar Specimens. Results of static strength tests on the unspliced control bar specimens are summarized in Table 4. A force-elongation plot was recorded for each test; the plots are presented in Appendix E. Nominal bar areas were used to calculate stresses from measured test loads. The tabulated yield strength for control bar specimens is based on a yield point observed from a pause of the load indicator, or obtained from the force-elongation plot using the load at an extension of 0.5 percent.

Tensile test requirements for unspliced bar are given in ASIM A 615. Pertinent requirements are listed in Table 4 along with the results of tests on control bar specimens. The tested yield and tensile strengths of all unspliced control bar specimens met the minimum yield strength and minimum tensile strength requirements specified by the ASTM standard for Grade 60 reinforcing bar.

5

Wiss, Janney, Elstner Associates, Inc.

SUMMARY

Monotonic tensile and compressivestrength tests were carried out on the S-Series Bar-Lock (MBT)

Coupler reinforcing bar mechanical connector system.

The S-Series coupler system consistently demonstrated monotonic tensile strengths and monotonic compressive strengths that exceed the strength requirements for mechanically connected reinforcing bars, as stated in Btilding Code Requirements for Reinforced Concrete (ACI 318-95), published by the American Concrete Institute.

Respectfully Submitted, WISS, JANNEY, ELSTNER ASSOCIATES, INC.

A AM,w,

6 P&&a;Sy9e,g C-F. Dirk Heidbrink, P.E.

Project Engineer Conrad Paulson, P.E., SE.

Project Manager CP:FDH:cp 6

TABLES

-J7 i

TABLE 1 -

SPECIFIED PHYSICAL DATA FOR S-SERIES BAR-LOCK (MBT) COUPLERS Coupler Bar Size Tube Dimensions l

olt Specifications Designation l Outside Diameter Length 1 Quantity Size Torque l_______

l (in.)

l (in.)

ll l____

(iin.)

l (ft-lb) l

1. 3/10M No. 3 1.3 3.9 4

1/2 40

1. 4/12M No. 4 1.3 3.9 4

1/2 40

1. 5/16M No. 5 1.7 4.5 4

1/2 80

1. 6/20M No. 6 1.9 6.3 6

1/2 80

1. 7/22M No. 7 1.9 8.0 8

1/2 80

1. 8/25M No. 8 2.2 8.0 6

5/8 150

1. 9/28M No. 9 2.9 9.0 6

3/4 295

1. 10/32M No. 10 2.9 9.0 6

3/4 295

1. 11/35M No. 11 3.1 11.5 8

3/4 360

1. 14/45M No. 14 3.5 16.5 12 3/4 360

1. 18/57M No. 18 4.3 27.9 20 3/4 475 r

TABLE 2 -

TENSILE STRENGTH OF S-SERIES BAR-LOCK (MBT) COUPLERS Bar Size/

Bar Slip Tensile Strength Failure Specimen Area (lbs)

(ksi)

(% fy)

Mode Identification (in2)

(in.)

(bs (ki 04-01 0.20

.0012 20,360 101.8 170 Pull-out 04-02

.0030 20,290 101.5 169 Bar break 04-03

.0036 20,510 102.6 171 Bar break ACI Minimum 15,000 75.0 125 05-01 0.31

.0022 29,800 96.1 160 Pull-out 05-02

.0023 32,600 105.2 175 Pull-out 05-03

.0031 31,200 100.6 168 Pull-out ACI Minimum' 23,250 75.0 125 06-01 0.44-

.0020 43,300 98.4 164 Pull-out 06-02

.0038 39,100 f 88.9 148

{

Pull-out 06-03

.0039 42,600 [

96.8 161 Pull-out ACI Minimum' 33,000 75.0 125 l

07-01 0.60

.0033 50,500 84.2 140 Pull-out 07-02 1

1.0042 50,400 84.0 140 Pull-out 07-03 j

.0038 48,900 81.5 136 Pull-out ACI Minimum'

______]

45,000 75.0 125 08-01 0.79

.0049 66,200 83.8 140 i

Pull-out 08-02

.0047 1 65,200 82.5 138 j

Pull-out 08-03

.0044 j

67,400 85.3 142 Pull-out ACI Minimum'

]

59,250 l

75.0 125 09-01 1.00

.0011 94,500 J 94.5 158 Pull-out 09-02

.0045 99,000 99.0 165 Pull-out 09-03

.0047 100,750 100.8 168 Pull-out ACI Minimum' 75,000 75.0 112 l

10-01 1.27

.0069 111,750 j 88.0 147 Pull-out 10-02

.0071 109,750 86.4 144 Pull-out 10-03 j

.0053 109,500 86.2 144 Pull-out ACI Minimum' 95,250 75.0 125 11-01 j 1.56

[__.0035 119,250 76.4 127 Pull-out 11-02

..0053 136,250 87.3 1 146 Pull-out 11-03 j

.0049 133,750 85.7 1 43 Pull-out.'

ACI Minimum' 117,000 750 1 25 14-01 2.25 l[

.0061 1 208,750 92.8 J

155 Pull-out 14-02

.0066 J 199,750 f 88.8 1 48 Pull-out 14-03

.0064 207,500 92.2 1 54 Pull-out AC Minimum' _ _

ll 168,750 75.0 25 18-01 4.00

.0093 11 357,800 89.5 149 Pull-out 11 18-02

_____1.0082 355,800 j 89.0 148 Pull-out 18-03

.0097 11 363,700 90.9 152 J

Pull-out ACI Minimum'_

11 300,000 [

75.0 125

[Note a:

Values listed in row are mininum values specified in ACI 318-95 for the indicated connector size.

TABLE 3 -

COMPRESSIVE STRENGTH OF S-SERIES BAR-LOCK (MBT) COUPLERS Bar Size/

Bar Compressive Strength Failure SpeCimen Area (1bS)

(kSi) l

(

Mode 04-04 0.20 17,830 89.2 149 Bar bent 04-05 18,000 90.0 150 No failure 04-06 18,000 90.0 150 No failure ACI Minimum' 15,000 75.0 125 05-04 0.31 28,000 90.3 151 No failure 05-05 28,000 90.3 151 fNo failure 05-06 I 28,000 90.3 151 No failure ACI Minimum 23,250 75.0 125 06-04 0.44 40,000 90.9 152 No failure 06-05 40,000 90.9 152 No failure 06-06 40,000 90.9 152 No faiUre ACI Minimum' 33,000 75.0 125 07-04 0.60 54,000 90.0 150 No failure 07-05 54,000 90.0 150 No failure 07-06 J 54,000 90.0 150 No failure ACI Minimum 45,000 75.0 125 1

08-04 0.79 72,000 911 152 I

No faiUre 08-05 11 72,000 91.1 152 No failure 08-06 IL 72,000 91.1 152 No failure ACI Minimum' 59,250 75.0 125 09-04 1.00 90,000 90.0 1150 No faiUre 09-05 1

90,000 190.0 1

1501 No failure 09-06 j

90,000 90.0 150 No failure ACI Minimum' I

]

75,000 75.0 125 10-04 l

1.27 115,000 1 90.6 1

151 No failure 10-05 115,000 j 90.6 1

151 No failure 10-06 J

115,000 90.6 151 No failure ACI Minimum' 95,250 75.0 125 11-04 1.56 11 140,400 90.0 150 No failure 11-05 140,400 90.0 150 No failure 11-06 l

140,400 90.0 150 No failure AC A Minimum4 117,000 75.0 125 14-04 1 2.25 202,500 1 90.0 J

150 No failure 14-05 I9

...202,S.0

.90.0

-.150_

.-No failure 14-06 198,000 88.0 147 No failure ACI Minimum' 168,750 75.0 125 18-04 1 4.00 360,000 90.0 150 No failure 18-05 l_

ll_360,000 90.0 150 No failure 18-06 l

ll 360,000 90.0 150 No failure ACI Minimum' II 300,000 75.0 125 l! ~i AC

___'I Note a:

Values listed in row are minimum values specified 11 in ACI 318-95 fr the indiCated COnLneCtOr SiZe.I

TABLE 4 - TENSILE PROPERTIES OF CONTROL BARS Bar Size/

Bar Yield Strength Tensile Strength Specimen Area Identification (inr2)

(Ibs)

(ksi)

(%Ify)

(Ibs)

(ksi)__

(°_(fy) 04s21 10.20 12,550 62.8 105 20,210 101.1 1 169 0422 12,510 62.6 104 20,330 101.7 170 04-23 12,770 63.9 107 20,540 102.7 171 ASTM Minimum' 12,000 60.0 100 18,000 90.0 150 05-21 0.31 20,500 66.1 110 32,700 105.5 176 05-22 20,800 67.1 112 32,800 105.8 176 05-23 21,250 68.5 114 32,900 106.1 177 ASTM Minimuma 18,600 60.0 100 27,900 90.0 150 06-21 0.44 27,500 1 62.5 104 45,300 103.0 172 06-22 J

26,500 60.2 100 45,400 103.2 172 06-23

{

28,000 63.6 106 45,600 103.6 173 ASTM Minimum' 26,400 60.0 100 39,600 90.0 150 07-21 0.60 38,900 64.8 108 63,400 j 105.7 176 07-22 39,600 66.0 110 63,400 J 105.7 176 07-23 39,800 66.3 III 63,600 106.0 177 ASTM Minimum 36,000 60.0 100 54,000 90.0 150 08-21 0.79 49,800 63.0 105 81,100 102.7 171 08-22 49,600 62.8 105 81,400 103.0 172 08-23 50,100 63.4 106 81,200 102.8 171 08-24 48,800 61.8 103

-. 80,100 l 101.4 169 ASTM Minimum' 47,400 60.0 100 71,100 90.0 150 09-21 1.00 66,700 66.7 ill 110,750 110.8 185 09-22 65,400 65.4 109 111,750 -

111.8 186 09-23 66,200 66.2 110 1 111,000 j 111.0 185 ASTM Minimum' 60,000 60.0 100 l 90,000 90.0 150 10-21 1.27 88,000 693 116 145,000 114.2 190 10-22 87,500 68.9 115 145,500 f 114.6 191 10-23 87,750 69.1 115

• l146,750 115.6 193 ASTM Minimum' 76,200 60.0 l

100 114,300 90.0 150 11-21 1.56 104250 66.8 i11 157,250 100.8 168 11-22 103,750 66.5 ill 157,250 100.8 1 168 11-23 107,750 69.1 1115 165,500 106.1 177 ASTM Minimum' 93,600 60.0 l

100 140,400 90.0 150 14-21 j

2.25 152,500 67.8 113 225,250 100.1 j

167 14-22

-149,500

.66A

. 111

.. 228,250

-1014 169 14-23 1150500 66 9112 224,500 99.8 166 ASrM Minimum' 135,000 60.0 100 202,500 90.0 150 18-21 14.00 325,000 81.3 136 496,300 124.1J207 18-22 J _

325,000 1.81.3 136 486,300 121.6 203 18-23 325,000 81.3 136 491,100 122.8 205 ASTM Minimum' 240,000 60.0 100 360,000 90.0 150 Note a: Values listed in row are minimum values specified in ASTM A615-94 for the indicated bar size

Topical Report 24370-TR-C-001-A Appendix B Cyclic Tests of S-Series Bar-Lock Couplers for Bar-Lock (MBT) Coupler Systems, Inc.

WJE No. 952595 June 5, 1996 9f Page 37 of 88

CYCLIC TESTS OF S-SERIES BAR-LOCK COUPLERS

- FOR

• BAR-LOCK (MBT) COUPLER SYSTEMS, INC WJE No. 952595 June 5, 1996 Wiss, Janney, Elstner Associates, Inc.

29 North Wacker Drive, Suite 555 Chicago, Illinois 60606 (312) 372-0555 I

Wiss, Janney, Elstner Associates, Inc.

CYCLIC TESTS OF S-SERIES BAR-LOCK COUPLERS FOR BAR-LOCK MBT) COUPLER SYSTEMS, INC.

WJE No. 952595 June 5, 1996 INTRODUCTION Wiss, Janney, Elstner Associates, Inc. (WJE), has conducted a series of tests on reinforcing bar mechanical connectors for Bar-Lock (MBT) Coupler Systems, Inc. (Bar-Lock). WJE tested mechanical connections made from S-Series Bar-Lock couplers in bar size Nos. 4 through 11 and 14. Tests reported herein include reversed-loading cyclic tests, performed according to a loading protocol established by ICBO Evaluation Service, Inc. (ICBO ES). The ICBO ES cyclic protocoL described in detail in the next section of this report, is a multi-stage test procedure in which the mechanical connection is first subjected to 20 elastic cycles below yield, then 4 inelastic cycles at each of two different strain levels above yield, and then tested to failure under increasing monotonic tension.

Companion coupler specimens were previously tested in monotonic tension and compression, and companion unspliced control bars were tested in monotonic tension. These companion specimens were assembled from the same production lots of couplers and reinforcing bar as the specimens reported herein. The results of the tests on companion specimens are presented in "Strength Tests of S-Series Bar-Lock (MBT) Coupler for Bar-Lock Coupler Systems, Inc.", dated May 24, 1996. The companion coupler specimens met the static strength requirements for mechanical connections of reinforcing bars contained in Building Code Reguirementsfor.Reinforced ConcretefAC.18-95),(prprulgatedxbythe American Concrete Institute (ACI). The companion control bars met the yield and tensile strength requirements of the "Standard Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement," ASTM Designation A615-94.

I

Wiss, Janney, Elstner Associates, Inc.

TEST PROCEDURES Test Specimens. The couplers utilized herein were assembled as part of the previously-cited WJE testing on S-Series Bar-Lock couplers, and had been designated as spare specimens at the time of the previous testing. Key physical data that have been specified for the S-Series couplers by Bar Lock are summarized in Table 1. Further descriptions of connector identification, specimen assembly procedures, and reinforcing bar sources may be found in the companion report.

Testing Procedures for Cvclically Loaded Specimens. Three S-Series couplers in each of size Nos. 4 through 11 and 14 were tested cyclically under reversed loading, using the following loading protocol as established by ICBO ES:

Load Tension Compression l No. of Stage Load I

Load Cycles 1

0.95 fg 0.5 fy 20 2

2 ev 5_fv 4

3 5 eV 0 5 fh 4

4 J Load in monotonic tension to failure where fy is the specified miniimum yieId strength of the reinforcing bar, and ey is the strain of the reinforcing bar at actual yield stress.

MTS servo-controlled universal test machines with hydraulic grips were utilized for the cyclic testing. Specimens of bar size Nos. 4 through 8 were tested in a machine with a capacity of 100,000 lbs, and larger specimens were tested in a machine with a capacity of 600,000 lbs.

Deformation (slip) of the splice during Stages 1 and 2 was measured by a pair of 1, VDTs installed in a frame having an adjustable gage length. Gage length of the LVDT test frame was as follows: 8.0 in.

for size Nos. 4, 5 and 6; 12.0 in. for size Nos. 7, 8, 9, 10 and 11; and 24.0 in. for size No. 14. Specimen bar strain was monitored during Stages 1, 2 and 3 at a point away from the splice using a clip-on strain gage with a gage length of either 1 or 2 in.

Compression loads and tension loads were programmed into the test machine servo-controller device. The compression load in all cyclic load stages was set to 0.5-(Ajfy), where As is nominal bar area 2

Wiss, Janney, Elstner Associates, Inc.

as listed in ASTM A615, andfy is a specified minimum yield strength of 60,000 psi. The tension load for Stage 1 was set to 0.95-(A,-fy). Tension load for Stage 2 was determiined by monitoring the specimen bar strain at a point away from the splice, and then applying load to the specimen until a strain reading of 2 ey was obtained. Tension load for Stage 3 was similarly obtained using a bar strain criteria of 5 !

The reinforcing bar strain, ey, was determined graphically from the average of the apparent yield strain results of tensile tests on unspliced control bars.

TEST RESULTS Previous Tests on Companion Specimens. Companion coupler specimens were previously tested in monotonic tension and monotonic compression, and companion unspliced control bar specimens were previously tested in monotonic tension. A full description of the companion tests may be found in the previously-cited companion report, "Strength Tests of S-Series Bar-Lock (MBT) Coupler for Bar-Lock Coupler Systems, Inc.", by WJE and dated May 24, 1996. The companion coupler specimens met the tensile and compressive strength requirement of 1.25,(Afty) for mechanical connections of reinforcing bars, as contained in Building Code Requirements for Reinforced Concrete (ACI 318-95).

The companion control bars met the yield and tensile strength requirements of the "Standard Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement," ASTM Designation A615-94.

For ease of reference, the results of some of these previous tests are summarized again herein:

the monotonic tensile tests on companion couplers are summarized in the attached Table 2, and the results of monotonic tension tests on companion unspliced control bars are summarized in the attached Table 3.

Couplers Tested Cyclically per ICBO ES Protocol. The ICBO ES cyclic test procedure includes the monitoring of.slipin theoupler durnyclidoad.Stagesl andA:

2 ereisno.monitoring of slip during Stage 3, but the specimen is required to survive the Stage 3 cycling without failure.

The requiremenit for Stage 4 is that the breaking strength of the specimen is a minimum of 1.35 fy 3

Wiss, Janney, EJstner Associates, Inc.

Results of the cyclic tests per ICBO ES protocol are summarized in Table 4. Slip during Stages 1 and 2 are noted in the table. All specimens survived Stage 3 cycling without failure. All but two specimens demonstrated a Stage 4 tensile strength in excess of 1.35 fy. These two specimens, Specimens 11-08 and 11-09, did exhibit a Stage 4 tensile strength in excess of 1.25 fy, which is the strength criteria as stated in Building Code Requirements for Reinforced Concrete.(ACI 318-95), published by the American Concrete Institute.

SUMMARY

Cyclic tests were carried out on S-Series Bar-Lock (MBT) reinforcing bar couplers in bar size Nos. 4 through 11 and 14. The S-Series Bar-Lock couplers consistently survived without failure the cyclic testing protocol stipulated by ICBO ES, the post-cyclic residual tensile strength for all but two specimens reported herein exceeded the tensile strength criteria of 1.35fy established by ICBO ES. Additionally, the post-cyclic residual tensile strength for all specimens reported herein exceeded the tensile strength criteria of 1.25 fy for mechanical connections as stated in Building Code Requirementsfor Reinforced Concrete (ACT 318-95), published by the American Concrete Institute.

Respectfully Submitted, WISS, JANNEY, EISrNER ASSOCIATES, INC.

e tE/

'A

/

F. Dirk Heidbrink, PE.

Project Engineer Conrad Paulson, PE., SE.

Project Manager CP:FDH:tkh 4

TABLES t

j l -:

TABLE 1 -

SPECIFIED PHYSICAL DATA FOR

• S-SERIES BAR-LOCK (MBT) COIPLERS Coupler Bar Size Tube Dimensions Bolt Specifications Designation j Outside Diameter Length jj Quantity Size Torque in) j (in.)

(in.)

(ft-lb)

1. 3/1OM No. 3 13 3.9 4

1/2 40

1. 4/12M No. 4 1.3 3.9 4

1/2 40

1. 5/16M No. 5 1.7 4.5 4

1/2 80

1. 6/20M No. 6 1.9 6.3 6

1/2 80

1. 7/22M No. 7 1.9 8.0 8

1/2 80.

1. 8/25M No. 8 2.2 8.0 6

5/8 150

1. 9/28M No. 9 2.9 9.0 6

3/4 295

1. 10/32M No. 10 2.9 9.0 6

3/4 295

1. 11/35M No. 11 3.1 11.5 8

3/4 360

1. 14/45M No. 14 3.5 16.5 12 3/4 360

1. 18/57M No. 18 4.3 27.9 20 3/4 475 r

TABLE 2-TENSILE STRENGTH OF S-SERIES BAR-LOCK (MBT) COUPLERS Bar Size/

Bar SlipD Tensile Strength Failure Identification (in) i.

Specimen A.rea (i.

(ls)l ki) l

°c y Mode 04-01 0.20

.0012 20,360 101.8 170 Pull-out 04-02

.0030 20,290 101.5 169 Bar break 04103

.0036 20,510 102.6 171 Bar break AG Miniimumi 15,000 75.0 125 l

05-01 0.31

.0022 29,800 96.1 160 Pull-out 05-02

.0023 32,600 105.2 175 Pull-out ACI Minimumd 23,250 75.0 125 06-01 0.44

.0020

-43,300 98A 164 Pull-out 06-02

.0038 39100 88.9 148 Pull-out 06-03

.0039 42,600 96.8 161 Pull-out ACI Miriimums 33,000 75.0 125 07-01 0.60

.0033 50,500 84.2 140 Pull-out 07-02

.0042 50,400 84.0 140 Pull-out 07-03 1

.0038 48,900 81.5 136 Pull-out ACI Minimuma ll___ll 45,000 75.0 125 l

08-01 0.79

.0049 66,200 83.8 140 Pul-out 08-02 f___

.0047 65,200 82.5 138 Pull-out 0803

.0044 67,400 85.3 142 Pull-out ACI Minimumd 59,250 75.0 125 09-01 1.00

.0011 94,500 94.5 158 Pull-out 09-02 1

• 0045 99,000 99.0 165 Pull-out 09-03 J

.0047 100,750 100.8 168 Pull-out AC Minimum 75,000 75.0 125 10-01 1.27

.0069 111,750 88.0 147 j

Pull-out 10-02

.0071 109,750 86.4 144 Pull-out 10-03

.0053 109,500 86.2 144 Pull-out AG Minimum 95,250 75.0 125 11-01 1.56

.0035 119,250 1 76.4 127 Pull-out 11-02 J _

.0053 136,250 87.3 146 uH-out.

11-03

.0049 133,750 85.7 143 Pull-out' AC Minimum 117,000 75.0 125 14-01 2.25

.0061 208,750 92.8 j

155 j

Pull-out 14-02 t-0066 8199750j

'B8.8

'148 i

ull-out 14-03 0064 207,500 922 l

154 Pull-out 1

AG Minimum 16 J

168,750 75.0 125 1

Note a: Values listed in row are minimum values specified in AG 318-95 for the indicated connector size.

Note b: Slip measurements made according to procedures of California Test 670.

(

TABLE 3 - TENSILE PROPERTIES OF CONTROL BARS Bar Size/

Bar Yield Strength Tensile Strength Specimen Aea TF Identification (in2)

(lbs) l (ksi) l (0/Ify)

(lbs) j (ksi)

(%fy) 04-21 020 12,550 62.8 105 20,210 101.1 169 04-22 12,510 62.6 104 20,330 101.7 170 04-23 12,770 63.9 107 20,540 102.7 171 AS}M Minimuma 12,000 60.0 1 100 18,000 90.0 150 05-21 0.31 20,500 66.1 110 32,700 105.5 176 05-22 20,800 67.1 112 32,800 105.8 176 05-23 21,250 68.5 114 32,900 106.1 177 ASIM Minimuma 18,600 60.0 100 27,900 90.0 150 06-21 0.44 27,500 62.5 104 45,300 103.0 172 06-22 1

26,500 60.2 100 1 45,400 1103.2 1172 06-23 28,000 63.6 106 45,600 103.6 173 ASIM Minimum 26,400 60.0 100 39,600 90.0 150 07-21 10.60 j38,900 64.8 j

108 63,400 105.7 176 07-22 1

39,600 66.0 110 63,400 1105.7 176 07-23 39,800 66.3 111 63,600 106.0 177 ASTM Miriimuml 36,000 60.0 100 54,000 90.0 150 08-21 10.79 49,800 63.0 105 81,100 102.7 171 08-22 1 _

49,600 62.8 1 105 81,400 103.0 172 08-23 50,100 63A 106 81,200 102.8 171 08-24 48,800 61.8 103 80,100 IOIA 169 ASTM Minimum 47,400 60.0 100 71,100 90.0 150 09-21 f

1.00 66,700 66.7 111 110,750 110.8 185 09-22 65,400 65.4 109 111,750 111.8 186 09-23 1

l667200 66.2 110 1l111,000 111.0 185 ASTM Minimuma 60,000 60.0 100 90,000 90.0 150 10-21 1.27 88,000 693 116 145,000 f 1142 J 190 10-22 (87,500 68.9 115 145,500 T 114.6 T 191 10-23 1 87,750 69.1 115 146,750 J 115.6 193 ASTM Minimuma a 76,200 60.0 100 114,300 J 90.0 J 150 11-21 1.56 104,250 66.8 111 157,250 J 100.8 1P8 11-22 103,750 66.5 111 157,250 J 100.8 168 11-23 1 107,750 69.1 115 165,500 J 106.1 177 ASTM Minimuma 93,600 60.0 100 140,400 90.0 150 14-21 2:25..

152,500.4 678 113

.225,250

.2.00.1 167 14-22 149,500 66.4 111111 228,250 101.4 1 169 14-23 150,500 66.9 1 112 224,500 99.8 j

166 ASIM Mininm a 135,000 60.0 j

100 202,500 90.0 150 Note a:

Values listed in row are minimum values specified in ASIM A615-94 for the indicated bar size 4

1L i.

TABLE 4 - RESULTS OF REVERSED-LOADING CYCLIC TESTS ON S-SERIES BAR-LOCK (MBT) COUPLERS Bar Size/

Stage 1:

Stage 2.

Stage 3:

Stage 4:

Specimen Cyclic Cyclic Cyclic Monotonic Tension Identification Cycles Slip Cycles Slip Cycles Statusa Tensile Strength Failure (in.)

(in.)

(lbs) l (% fv)

Mode 04-07 20 0.010 4

0.023 4

NF l19,460 162 Puuout 04-08 20 0.010]l 4

0.029 4

NF 20,460 171 Bar break 04-09 20 0.009

]4 0.021 4

NF 18,260 152 Pulout l

1 T105-07 20 0.006 4

0.016 4

NF 32,040 l 172 Puuout 05-08 20 0.008 4

0.017 4

NF 1 28,870 155 Pulout 05-09 20 0.008 4

10.0241 4

lNF 30,8001 166 Pullout 06-07 20 0.013 [

4 0.023 4

l NF ] 42,530 J 161 ] Pulout 06-08 1[ 20 0.014I 4

0.025 4

NF 142,050 1159 Puuout 06-09 ll 20 0.008[

4 0.019 4

NF 1 41,530 l 157 Pulout 07-07

[20 0.016*l 4

0.046 l4 NF l50,100 139 Punout 07-08

[20 0.013 4

0.044 4

l NF ll 53,170 148 Pullout 07-09 I

20 0.011 4

0.038 4

NF 1 54,960 j 153 j

Puuout l

08-07

[20 0.017 [4 0.033 l4 NF 65,580 138 Pulout 08-08 f 20 J 0.014*j 4

0.045 4

NF 1.66,8001 141 J

Puuout 08-09 l

20 0.013l 4

0.028 4

NF 65,680 139 Pulout 09-07 20 0.009 4

0.024 4

NF 98,600 164 Puuout 09-08 20 0.011 4

0.023 4

NF 104,400 174 Partial slip, then bar break at first bolt 09-09 20 0.016 4

0.034 4

N 95,400 159 Pullout 10-07 20 0.012 4

0.035 4

NF 112,800 148 Puuout 10-08

[ 20 0.011 4

0.033 4

NF 124,200 163 Pullout 10-09 l 20 0.011 4

0.031 4

NF 115,900 152 Bar break l

l at first boltl 11-07 20 0.0139 4

10.042 4

NF 132,600 142 Pullout 11-07 20 0.019]

4 10.047 4

NF 118,600l 127 T Pullout 11-09 20 l0.027.l 4

0.058 4

NF 12 0,2 00 12 8 Puuout 14-07 20 10.021 If 4 10.053 4

193,200 143 l Puuout 14-08 f[ 20 0.011 4

0.044 1 4

NF 190,800 141 l Pullout 14-09 ff 20 0.020 If 4 0.057 If 4 NF 197,0001 146 1 Puuout

[Notes:

a:

NF

- No failure during stage 3 cycling.

1 f

Topical Report 24370-TR-C-OO1-A Appendix C Cyclic-Tests of L-Series Bar-Lock (MBT) Couplers for Bar-Lock (MBT) Coupler Systems, Inc.

WJE No. 962136 October 16, 1997 Page 48 of 88

Wiss, Janney, Elstner Associates, Inc.

CYCLIC TESTS OF L-SERIES BAR-LOCK (MBT) COUPLERS FOR BAR-LOCK (MBT) COUPLER SYSTEMS, INC.

WJE No. 962136 Original Issue July 2, 1997 Revised October 16, 1997 Wiss, Janney, Elstner Associates, Inc.

330 Pfingsten Road Northbrook, Illinois 60062 (847) 272-7400 Iji.

Wiss, Janney, Elstner Associates, nc.

CYCLIC TESTS OF L-SERIES BAR-LOCK (MBT) COUPLERS FOR BAR-LOCK (MBT) COUPLER SYSTEMS, INC.

WJE No. 961236 October 16, 1997 INTRODUCTION Wiss, Janney, Elstner Associates, Inc. (WJE) has conducted a series of cyclic tests on L-Series reinforcing bar mechanical connectors for Bar-Lock (MB7) Coupler Systems, Inc. Tests were conducted on three bars in each of bar size Nos. 4, 5, 6, 7, 8, 9, 10, 11 and 14. The purpose of the tests was to evaluate the performance of the couplers after fatigue loading utilizing procedures established by the City of Los Angeles:

100 cycles of tensile load varying from 5-percent to 90-percent of the specified yield strength of reinforcing steel. The tests were also compared to the requiremnts outlined in the 1997 Uniform Building Code (Section 1921.2.6).

Unspliced control bar specimens of size Nos. 4, 5, 6, 7, 8, 9, 10, 11, and 14 in bar Grade 60 were also tested. The control bars came from the same lots of bars as used in fabricaLion of the connector specimens. The control bar tests were performed to determine the yield strength and tensile strength of the unspliced reinforcing bar. The results of the control bar tests were compared to the requirements of he "Standard SpecificaLion for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement," ASTM Designation A615-94. It should be noted that the reinforcing bar for testing bar size No. 10 was ASTM A706-93a.

SPECIMEN ASSEMBLY AND TEST PROCEDURES Splice Assembly Procedure - The mechanical splice is comprised of one L-Series Bar-Lock coupler.

sleeve, which is used to connect two pieces of reinforcing bar. Each coupler test specimen consisted of two lengths of reinforcing bar connected by the applicable size coupler. The reinforcing bars used in fabricaLing Lhe specirens were supplied by B ar-Lock. B ar-Lock represents that the bar for each size tested was obtained from 1

Wiss, Janney, Elstner Associates, nc.

a single source. Specirrens were assernbled by Bar-Lock personnel in accordance with their written installation instructions and then shipped to the WJE laboratories for testing.

Testing Procedures for Control Bar Specimens - Unspliced reinforcing bar specimens were tested monotonically in axial tension in accordance with "Standard Test Methods and DefiniLions for Mechanical Testing of Steel Products,' ASTM A 370. All tests were directed by a licensed professional engineer who is a WJE staff rmmber. A pair of LVDTs installed in a frame having ari adjustable gage length measured elongation of each unspliced control bar test specimen. The electrical signal output from the LVDTs and an electrical signal indication of the test machine load were simultaneously monitored by an X-Y chart recorder, which provided force-elongation plots for all tension test specirens. Gage length of the LVDT test frame was 8.0 iL City of Los Angeles Cyclic Test Procedure - For each bar size, three coupled specimens were loaded cyclically prior to the monotonic tension test to failure. The specimens were loaded from 5% to 90% F, using a Haversine wave form at a rate of 0.5 cycles per second for 100 cycles. After completion of the cycles, each specimen was nonotonically loaded in tension to failure. The City of Los Angeles test procedure states that the average tensile strength of the splices shall not be less than 90-percent of the average actual (tested) tensile strength of the unspliced reinforcing bar nor less than 100-percent of the specified minimun tensile strength of the bar.

1997 Uniform Building Code Test Requirements - The 1997 Uniform Building Code states in Section 1921.2.6 that mechanical connections develop in tension the lesser of 95-percent of the [average actual]

ultimate tensile strength or 160-percent of the specified yield strength of the unspliced reinforcing bar.

r TEST RESULTS Control Bar Specimens - Results of static strength tests on the unspliced control bar specimens are summarized in Table 1. A force-elongation plot was recorded for each test; the plots are presented in Appendix A. Nominal bar areas were used to calculate stresses from measured test loads.

he tabulated yield' strength for control bar specimens is based on a yield point observed from a pause of the load indicator.

Tensile test requirerments for unspliced bar are given in ASTM A615-94. Pertinent requirements are listed in Table 1 along with the results of tests on control bar specimens. The tested yield and tensile strengths I

2

Wiss, Janney, Eistner Associates, Inc.

of all unspliced control bar specimens met the minimurm yield strength and miniimum tensile srength requirernents specified by the ASTM standard for Grade 60 reinforcing bar. Size No. 10 bar reets the tensile strength criteria for both ASTM A615-94 and ASTM A706-93a.

Coupler Test Results - Results of static tensile strength tests on L-Series Bar-Lock (MBT) couplers after cyclically loaded in accordance with City of Los Angeles test procedures are summarized in Table 2. A.

summary conparing the average tensile strengths of couplers after cycling to 90-percent of the average tested tensile strength of the unspliced bar is shown in Table 3. The results shown in Table 3 indicate that the average coupler tensile strength for all bar sizes tested exceed both 100-percent of the specified rninirum tensile strength and 90-percent of the average actual tensile strength of the unspliced reinforcing bar. Also included in Table 3 is a conparison of the average tested tensile strengths of the couplers to the IJBC Section 1921.2.6 requiremnts. The results indicate that the couplers exceed either 95-percent'of the average actual ultirate strength or 160-percent of the specified yield strength of the unspliced reinforcing bar.

SUMMARY

Strength tests were carried out on the L-Series Bar-Lock (MBT) Coupler reinforcing bar nechanical connector system after application of cyclic loads in accordance with the City of Los Angeles test procedure.

The L-Series coupler system consistently dermnstrated mnotonic tensile strengths that exceeded the specified strength requirernents after cyclic loading in all bar sizes tested herein. The L-Series coupler system also exceeded the specified strength requirements in the 1997 Uniform Building Code.

Respectfully Subritted, WISS, JANNEY, F$TNER ASSOCIATES, INC.

F. Dirk Heidbrink, P.E.

Project Manager FDH:ah 100435 3

Wiss, Janney, Elstner Associates, Inc.

TABLE 1 - TENSILE PROPERTIES OF CONTROL BARS Bar Size/

Bar Specimen Area Yield Strength Tcnsilc Strength IdentiFicalion (in^A21 )

.j Identiricalion (inA2)

(Ibs) l (ksi) l

(%r,)

(Ibs) l (ksi) T e,

04L,21 0.20 13,900 69.5 116 f 22.350 111.8 186 04L-22 14.380 71.9 120 22.570 112.9 188 04L-23 14,070 703 117 22.340 111.7 186 ASTM Minimum' 12.000 60.0 100 18.000 90.0 150 05L-21 0.31 19.380 62.5 104 30.600 98.7 164 05L-22 J

19.440 62.7 1I5 30,700 99.0 165 OSL-23 t

19.480 62.8 105 30.800 99.4 166 ASTM Minimum' 18,600 60.0 100 27,900 90.0 150 06L,21 J

0.44 27.500 62.5 104 44,500 101.1 168 06L-22 l _

27,700 62.9 105

.44.700 101.6 169 06L,23

-ll 21.90 l

63.4 l

106 ll 44,900 l

102.0 l

170 ASTM Minimum' l

ll

.26.400 60.0 100 39,600 90.0 150 07L-21l 0.60 38,000 63.3 106 62,300 103.8 173 07L-22 f_ __

38.700 64.5 107 62,000 103.3 172 07L-23 f

38.100 63.5

• 106 61.500 102.5 171 ASTM Minimum' 36,000 60.0 100 54.000 90.0 ISO 08L.21 l

0.79 l

52,100 65.9 110 83,500 105.7 176 08L-22 49,100 62.1 104 81,200 102.8 171 08L-23 49.100 l

62.1 104 81.600 103.3 172 ASTM Minimum' 47,400 1

60.0 100 71,100 90.0 150 09L-21 1.00 65.400 l

65.4 l

109 104.500 104.5 174 09L-22 l

65.800 65.8 110 106,200 106.2 177 09L-23

}

65,600 65.6 109 106,400 1 06.4 177 ASTM Minimum' 60,000 60.0 100 90.000 90.0 150 IO1.21 1.27 82.500 l

65.0 J

108 122.000 96.1 160

-I1L.22 82.900 j 65.3 -1 109 122.300 96.3 161 1OL_3 1

82,500 j 65.0 108 121.600 96.0 160 ASTM Minimum' 76.200 60.0 l

100 114.300 90.0 150 iL-21 l

1.56 104,600 l

67.1 l

112 152,000 97.4 l

162 I IL-22 l

ll 104,800 67.2 112 152.300 98.3 l

164 1 1 IL-23 11 104,400 66.9 II I1 51I3,1I00 98.116 ASTM Minimum' 93.600 60.0 100 140.400

90.

160 14L,21 2.25 159,700 71.0 118 242,700 107.9 180 14L-22 160,500 71.3 119 l242,400 107.7 ISO 14L.23 160,500 71.3 119 242.400 107.7 180 ASTM Minimum' 135,000 60.0 100 l

202,500 90.0 150 Note a:

Values listed in row are minimum values specirfled in ASTM AG15-94 for the indicated bar size

Wiss, Janney, Elstner Associates, Inc.

TABLE 2 - CYCLIC LOAD TEST RESULTS OF L-SERIES LAI-LOCK COUPLERS C clic Load Range l rnsile Strengti Samplle lin = 0.05 F1.

lIax = 0.90 Fy N

(lbs)

(IbsJ (Ibs)

(psi

% FJ.

N.

.ls (pi 0JL-I 22.920 114.600 191 04L-2 600 10.800 22.740 113,700 190 04L-3 22,730 1 13.600 190 Avcrage 114,000 190 05L-1 31,250 100,800 4

168 OSL-2 930 16.740 31.370 101.200 4

169 OSL-3 31,480 101,500 169 Averagc 101,100 169 06L-t 45,510 103,400 172 06L-2 1,320 23,760 45,570 103.600 173 06L-3 45.370 103.100 172 Average 103,400 172 07L-1 4

4 63,300 105,500 176 07L-2 f

1,800 32,400 60,290 100,500 168 07L-3 61,680 102.800 171 Average 102.900 172 OSL-I i

74,900 94,800 158 08L-2 2.370 42.660 82,280 104,200 174 08L-3 j

80,610 102,000 170 Avcrage 100.300 167 09L-96,610 96.610 161 09L-2 3.000 54,000 96,850 96,850 l

162 09L-3 l

l 1

103,800 103.800 173

_9L-3 4 Avcrage 99.100 165 10L-1 121,300 95,500 159 IOL-2 3.810 68,600 116,200 91.500 152 IOL-3 l

l 1

120,S0J l

95.100 158 Il OL-3l Average 94.000 156 I IL-I 163,700 104.900 17; I IL-2 4,680 l

4.240 161,800 103.700 173 I IL-3 l

15.80 l

101.800 170 Average 103,500 173 14L-1 221,500 9S.400 164

]

14L-2 6,750 121.500 234,500 1

04,200 174 14L-3 234,000 104.000 173 Avcrage 102.200 170

.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

5 r

40-

Wiss, Janney, Elstner Associates, Inc.

TABLE 3 -

SUMMARY

OF CYCLIC LOAD TEST RESULTS OF L-SERIES BAR-LOCK COUPLERS CITY F Fl.

ANfv.liIArq RIIIDIIMVNT J

90% of Average 100% of te 95% of the Average 160% of lhe I Average Coupler Tested Tensile Strength Specified Tested Tensile Strength Specified Yield Bar Size Tensile Strength of Unspliced Bar Tensile Strength of Unspliced Bar Strength j

(psi)

(psi)

(psi)

(psi)

(psi) 4 114,000 100,900 90,000 106,500 96,000 5

101,100 89,100 90,000 94,100 96,000 6

103,400 91,400 90,000 96,500 96,000 7

102,900 92,900 90,000 98,000 96,000 8

100,300 93,500 90,000 98,700 96,000 9

99,100 95,100 90,000 100,400 96,000 10 94,000 86,500 90,000 91,300 96,000 I

103,500 88,100 90,000 93,000 96,000 4.102,200 97,000 90,000 102,400 96,000 6

11

llRr, in47 mRF(mIIR.hmm~rq

Topical Report 24370-TR-C-001 -A Appendix D ICBO-ES Cyclic Tests on L-Series MBT Couplers for Bar-Lock Coupler Systems WJE No. 982850-A October 27, 1999 r

Page 56 of 88

Wiss, Janney, Elstner Associates, Inc.

ICBO ES CYCLIC TESTS ON L-SERIES NBT COUPLERS FOR BAR-LOCK COUPLER SYSTEMS WJE No. 982850-A October27, 1999 WISS, JANNEY, ELSTNER ASSOCIATES, INC.

120 N. LaSalle Street, Suite 2000

. Chicago, llinois 60602 (312) 372-0555 i

Wiss, Janney, Elstner Associates, Inc.

ICBO ES CYCLIC TESTS ON L-SERIES ?MT COUPLERS FOR BAR-LOCK COUPLER SYSTEMS WJE No. 982850-A October 27, 1999

- INTRODUCTION Wiss, Janney, Elstner Associates, Inc. (WJE), has conducted a series of monotonic compression and reversed-loading cyclic tests on reinforcing bar mechanical splices for Bar-Lock Coupler Systems (Bar-Lock). The tests were conducted on L-Series MBT mechanical splices in bar size Nos. 4 through 11 and 14. The test procedures were in general accordance with "Acceptance Criteria for Mechanical Connectors for Steel Bar Reinforcement," AC133, January 1998, issued by ICBO Evaluation Services (ICBO ES). A copy of this document can be found in Appendix A.

The primary purpose of the tests reported herein is to provide data to ICBO ES for acquiring an evaluation report on the L-Series MBT coupler system. A secondary purpose of the tests is to compare the tensile strength performance of this splice with tensile strength requirements for seismic reinforcing bar mechanical splices included in Building Code Requirements for Reinforced Concrete ( CI 318-99),

promulgated by the American Concrete istitute (ACI).

Unspliced control bar specimens were also tested. For each bar size, the control bars came from the same lot of bar used to make the splice specimens, which were assembled using ASTM A615, Grade 60 reinforcing bar. The control bar tests were perforned to deterrnine the yield strength, yield strain, tensile strength and final elongation of the unsplliced riiforcing bar.- The results of the control bar tests were compared to the requirements of the "Standard Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement," ASTM Designation A615-96b.

I

Wiss, Janney, Elstner Associates, Inc.

SPECIMEN ASSEMBLY AND TEST PROCEDURES Connector Identification. Assembled splice specimens were provided to W)E by Bar-Lock.

WTE witnessed assembly of select splice specimens, and observed that assembly was in accord with Bar-Lock procedures.

Figure 1 schematically illustrates the typical Bar-Lock L-Series MBT coupler.

Specified dimensions for L-Series vBT couplers are summarized in Table 1. Representative couplers in each size were compared to Bar-Lock standard drawing No. L-SUM, with revisions dated September 1999, and other related Bar-Lock standard drawings for the L-Series MBT couplers. The devices tested have the same appearance as the devices represented by the drawings.

Selected dimensions were measured and were found to agree with the dimensions indicated in Table I and on the standard drawing L-SUM, with tolerances as stated on the standard drawings.

Control Bar Specimens and Reinforcing Bar Sources.

Bar-Lock provided to WJE the unspliced control bar specimens. Bar-Lock represents that all pieces of reinforcing bar in each size, whether a control bar specimen or in an assembled splice specimen, came from the same lot of reinforcing steel. Bar-Lock also indicated the reinforcing bar is ASTM A615, Grade 60. Mill marks found on the reinforcing bar confirm the bar type and grade.

Test Procedures for Monotonic Tension Tests. Unspliced control bar specimens and certain selected spliced bar specimens were tested monotonically in axial tension in accordance with "Standard Test Methods and Definitions for Mechanical Testing of Steel Products," ASTM A370.

A pair of LVDTs installed in a frame having an adjustable gage length measured elongation of each unspliced control bar test specimen.

The electrical signal output from the LVDTs and an plectrical signal indication of the test machine load were simultaneously recorded by an analog X-Y chart recorder, or were digitally.recorded an a computer.

Force-elongation plots for all control bar specimens were produced either by the analog chart or by plotting the digital record. Gage length of the LVDT test frame was 8.0 in. for the unspliced bar specimens. This same instrumentation was also utilized on spliced bar 2

Wiss, Janney, Elstner Associates, Inc.

specimens tested in monotonic tension. Gage lengths for the spliced bar specimens are given later in this report.

For unspliced bar specimens, final elongation after fracture was deterrnined by first scribing a series of gage marks onto the central length of the untested specimen at 2.0 inch intervals over a total length of at least 8.0 in. After the test, the ends of the fractured specimens were carefully fit together, and a measurement was made of the distance between two scribe points having an original gage length of 8.0 in. and appro"ximately centered on the fracture location.

The elongation was calculated as the increase in length of the gage length. Final elongation was not determined for spliced bar specimens.

Compression Tests on Splice Specimens.

Shortening of all compression sleeve splice test specimens was obtained by using an electrical output from an LVDT, internal to the test machine, that monitored test machine piston position. For this type of test machine, piston movement is the same as crosshead movement in other types of test machines. Piston movement was taken to directly represent shortening of compression specimens because the clear length of reinforcing bar between the ends of the coupler and the test machine grip was relatively short. The electrical signal output from the intemal LVDT and an electrical signal indication of the test machine load were digitally recorded by a computer.

The digital record was used to produce force-deformation plots for the compression test specimens.

The clear length between test machine grips was kept to a minimum in order to prevent buckling of the specimen in compression. Approxirnate clear gage length between test machine grips at zero compressive load was 8, 9.0, 10.0, 11.8, 12.1, 13.8, 14.5, 19.0, and 22.0 inches for specimens in bar size Nos. 4, 5, 6, 7, 8, 9, 10, 11 and 14, respectively. These distances are approxirmately equal to the length of the splice plus one bar diameter at each end of the splice.

Testing Procedures.fdfC^dlicallytoaded Specimens: -Reversed-cad cyclic -tests utilized the following loading protocol, as established by ICBO ES in the AC133 document:

3 U

Wiss, Janney, Elstner Associates, Inc.

l Load Tension Compression No. of Stage Load.

Load I Cycles !

1 0.95f, I

0.5f 20 2

1 2 y O. 5fy 4

3 5

I 0.5fy 4

l 4

Load n monotonic tension to failure I

wheref, is the specified minimum yield strength of the reinforcing bar, and y is the strain of the reinforcing bar at (actual] yield stress.

Elongation (slip) of the splice during Stages 1, 2 and 3 was monitored by a pair of LVDTs installed in a frame having a gage length of 8, 8, 10, 12, 12, 15, 16, 19 and 24 in. for specirnens in bar size Nos. 4, 5, 6, 7, 8, 9, 10, 11 and 14, respectively. Strain in the reinforcing bar was monitored for reference purposes during Stages 1, 2, 3 and 4 at a point away from the splice zone using a clip-on strain age with a gage length of 2 in.

Test machine piston position was also monitored.

The instrumentation setup is schematically illustrated in Fig. 2.

Compression loads and tnsion loads for Stages 1, 2 and 3 were program.med into the test machine controller, which was operated under load control for the cycling. The compression load in all cyclic load stages was set to 0.5.(A,f,), where A, is nominal bar area as listed in ASTM A615, andfy is a specified minimum yield strength of 60 ksi. The tension load for Stage I was set to 0.95-(A,-f). Tension load for Stage 2 was determined by applying strain to the splice specimen until the bar reference strain reached the value of 2,; the load in the test machine at that strain value was then recorded and subsequently utilized as the Stage 2 maximum load. Maximum tension load for Stage 3 was similarly obtained using a target value of 5 Ey for the bar reference strain. The bar yield strain,

, was determined in advance from the apparent yield strain values obtained_graphically from the load-elongation curves for the unspliced control bars.

After the Stage 1, 2 and 3 cyclic loading, each splice specimen was monotonically loaded in tension to failure. The Stage 4 tests were carried out in accordance with "Standard Test Methods and Definitions for Mechanical Testing of Steel Products," ASTM A370. The test machine was operated in 4

Wiss, Janney, Elstner Associates, Inc.

displacement control during Stage 4. The LVDT frame instrument remained on the specimen and the elongation (slip) across the splice was recorded during the initial portion of the Stage 4 test to failure.

When the test load reached a value of approximately 120 percent of actual bar yield, the LVDT frame was removed from the specimen so that the instrument would not be damaged when the specimen fractured.

After removal of the instrumentation, displacement was increased until the specimen fractured.

Test machine crosshead movement (i.e., piston position) was monitored by computer throughout the test, up to and including specimen fracture. The peak load indicated by the test machine and the observed type of fracture were recorded for each specimen.

Test Machines. Some unspliced control bar tests were carried out in either a 120 kip Satec universal testing machine or a 500 kip Riehle universal test machine, located at the WJE laboratory facility in Norhbrook, Illinois. All cyclic tests, all compression tests and all tension tests on spliced bar specimens, and some tension tests on control bar specimens, were carried out in either a 600 kip, 100 kip or 50 kip MTS universal test machine having hydraulic grips. The current calibration certificates for all test machines are provided in Appendix B.

The MTS test machine is located at the Structural Engineering Research Laboratory (SERL),

University of Illinois, Urbana, Illinois. WJE has reviewed the competence and compliance of SERL with the portions of ICBO ES document AC89 relevant to the services provided by SERL to WJE, and WJE finds SERL acceptable. Details of the WJE review are provided in Appendix C.

TEST RESULTS The tests were carried out at various times during the period of February to August, 1999. All tests were directed by a licensed professional engineer who is a WJE staff member. The results of the tests are described in the following paragraphs.

Unspliced Control Bars. Unspliced control bars were tested for each bar size. The results of the tests on the unspliced control bars are summarized in Table 2. For the No. 10 control bars, Test 0593 is the control for the No. 10 compression test specimens, and Tests 0681 and 0682 are both controls for L...

L 5

Wiss, Janney, Elstner Associates, Inc.

the No. 10 cyclic and monotonic tension tests.

The tensile properties of all control bar specimens conform to the requirements of ASTM A615-96b. Load-elongation curves for the control bars can be found in Appendix D.

Connectors Tested in Compression. Five splice specimens were tested in compression for each bar size. Results of the compression tests are summarized in.Table 3. A force-deforrnation plot was recorded for each test; the plots are presented in Appendix E. To avert the failure of a specimen due to compression buckling or compression instability, testing of all compression specimens was halted at a load corresponding to a nominal compressive stress of approximately 90 ksi (150 percent of specified bar yield strengthfy).

Loading on the group of compression specimens in size No. 10 was initially halted at a compressive load that was less than the compressive strength requirement of AC133. These specimens were subsequently loaded to a compressive load in excess of the strength requirement For each No. 10 compression test specimen, the force-deformation curves for both the initial loading and the subsequent re-loading are shown on the same plot in Appendix E. It is our opinion that this multiple loading sequence neither beneficially nor adversely influenced the results of the compression tests.

The AC133 acceptance criteria requires that a mechanical connection develop in compression a strength of 125 percent of specified yield strengthfy of the bar. This corresponds to a value of 75 ksi for a specified yield strength of 60 ksi. The UBC 1997 and ACI318-99 have the same compressive strength requirement. The compressive strength of all couplers sumrnarized in Table 3 meet the AC 133, UBC and ACI 318 requirements for a mechanical connection in compression.

Some tests listed in Table 3 are noted to have ended with buckling of the specimen. This was a buckle of the bar-and-splice assembly;--not r-k1e'vfthe -coupling.sleeve.-T7he buckling occurred because the clear length of the bar-and-splice test specimen was relatively long for the applied loads.

The buckling does not represent inadequate performance of the coupling sleeve. These are valid tests i

6

Wiss, Janney, Elstner Associates, Inc.

because the compressive loads sustained by specimens that buckled exceeded the previously-summarized compressive strength requirements.

Splices Tested Cyclically per ICBO ES AC133 Protocol.

Results of the cyclic tests per ICBO ES protocol are summarized in Table 4.

Five specimens were tested in each bar size. Load-elongation (load-slip) curves for the splice specimens can be found in Appendix F. Load-strain curves for the reference strain in the reinforcing bar on the cyclically loaded splice specimens can be found in Appendix G. Load-crosshead movement (load-piston movement) curves, which trace overall specimen lengthening through to the occurrence of fracture, can be found in Appendix H. Minimum and maximum loads for the cycling of Stages 1, 2 and 3 are noted in Table 4, as are the numbers of cycles accomplished during each stage of cycling. The Stage 4 breaking strengths of the specirnens are also noted in Table 4, along with the mode of fracture for the specimens.

The ICBO ES AC133 cyclic test procedure requires the recording of load-elongation (load-slip) curves for the splice specimens during the cyclic testing. While AC 133 has no numeric criteria for slip, each splice specimen is required to survive the cyclic loading of Stages 1, 2 and 3 without brealing. All specinens summarized in Table 3 survived the prescribed number of cycles for Stages 1, 2 and 3 without breaking.

Three modes of fracture were observed: fracture of the reinforcing bar away from the splice; pull out of the reinforcing bar from the sleeve; and fracture of the bar within the splice.

The first specimen in size No. 4 (Test 0537) buckled during Stage 3 cycling. The length of this test specimen was shortened and testing resumed. It is our opinion that the remounting and confinued testing of this specimen did not beneficially influence the results of this particular test, and that the test is valid.

During the resumed test, data were inadvertently not recorded electronically.

The buckling does not represent inadequate performance of the splice, but rather occurred because the clear length of the test specimen was too long. The subsequent No. 4 specimens were tested with shorter lengths and therefore did not buckle.

7

Wiss, Janney, Elstner Associates, Inc.

The AC 133 strength requirement for Stage 4 loading in tension is that the mechanical splice specimen develop the lesser of 95 percent of the [actual] ultimate tensile strength of the bar or 160 percent of the specified yield strength,f,, of the bar. This is the same as the requirement found in the 1997 edition of the Uniform Building Code (UBC), Section 1921.2.6.1.2, for a Type 2 mechanical splice, which is permitted for use in the plastic hinge regions of reinforced concrete structures designed for earthquake loading. The strength requirernent for each size of splice is summarized in Table 5. It can be seen in Table S that the final strength requirement for splices in size Nos. 4 though 11 is 96.0 ksi, and the requirement for size No. 14 is 92.5 ksi.

The Stage 4 strength of all couplers summarized in Table.4, except for one specimen in size No. 10 (Test 0684) and one specimen in size No. 11 (Test 0638), meet the strength requirement of AC133 and UBC 1997. It is our opinion that the result of Test 0638 in size No. 11 does not deviate significantly (deviation is less than I percent) from the tabulated strength requirement, particularly when variability and tolerances inherent with laboratory testing are considered.

Consequently, Test 0638 should be taken as meeting the stipulated strength requirement.

The result of test No. 0684 in size No. 10, however, does deviate somewhat from the requirement.

Therefore, five supplemental monotonic tensile tests were carried out on spliced bar specimens in size No. 10. The results are summarized in Table 6, and data plots for these tests are included in Appendices F, G and H. The results of all of the supplemental tests meet the strength requirement stipulated by AC 133 and UBC 1997.

The Chapter 21 seismic provisions of ACI 318-99 includes a Type 2 mechanical s4plice, which is permitted for use in sections of concrete members where yielding of reinforcement is likely to occur as a result of inelastic lateral displacements under earthquake-loading.

Section 21.2.6.1 of ACI 318-99 states that a Type 2 splice shall develop in tension the specified tensile strength of the spliced bar. For each size of coupler, the minimum strength according to 4CI318-99 is also sumrarized in Table 5. The 8

Wiss, Janney, Elstner Associates, Inc.

tensile strength of all splice specimens summarized in Tables 4 and 6 exceed the ACI 318 minimum strength requirement for a Type 2 seismic mechanical splice.

SUMMARY

Wiss, Janney, Elstner Associates, Inc. conducted a series of monotonic compression and reversed-loading cyclic tests on the L-Series MBT mechanical coupler produced by Bar-Lock Coupler Systems. All splice specimens that were loaded in compression had compressive strengths that exceeded the compressive strength requirements of ICBO ES AC133, UBC 1997 and AC1318-99. No failures occurred when splice specimens were cyclically loaded as prescribed by AC133. These specimens were then loaded in monotonic tension to fracture. Supplemental monotonic tensile strength tests were also conducted on splice specimens of a select size.

The testing demonstrated compliance of the MBT L-Series couplers with acceptance criteria for a Type 2 seismic mechanical splice according to provisions of ICBO ES AC133 (January 1998) and UBC 1997. The cyclic tensile strengths and monotonic tensile strengths also exceeded the minimum strength requirements for a Type 2 seismic mechanical splice according to Chapter 21 of AC1318-99.

Respectfully Submitted, WISS, JANNEY, ELSTNER ASSOCIATES, INC.

Conrad Paulson, P.E., S.E.

Project Manager CP/cp 9

! L-

FIGURES r

(4)

(II

11)

(3)

(2) 15) 717~~~~~

(I) Caoupler barrel (2) Reinfordng Lar

13)

Ladhs hear Belts (4) Center le e for (3) (4)

12)

'~~~~~~~~~~~~~~~cnter stop' (5)

Setr ted strips Figure 1 - Schematic illustration of Bar-Lock MBT coupler (2)

(3)

TE5T MACHINE GRIF OR CRO55HEAD RErNFORCING BAR SPLICE f

Figure 2 - Test lstrumentation Setup

TABLES t

Wiss, Janney, Elstner Associates, Inc.

TABLE 1-SPECIFIED DIMENSIONS FOR L-SERIES MBT COUPLERS Designation Length Outside Inside Number Bolt Size (mm)

Diameter Diameter of (diarn.,

(mm)

(mm)

Bolts mm)

1. 4/13M 100 33.4 20.7 4

tACi

1. 5/16M 140 33.4 20.7 6

Mi

1. 6/19M 204 48.3 31.3 8

M12

1. 7/22M 248 48.3 31.3 10 M12

1. 8/25M 258 57.0 38.0 8

M16

1. 9/29M 292 73.6 45.6 8

M20 10/32M 356 73.6 45.6 10 M20 1 11/36M -

420 79.2 51.2 12 M20

1. 14/43M 484 88.9 60.9 14 M20 TABLE 2 -TESTS ON UNSPLICED CONTROL BARS Test Bar Bar Yield Strength, Yield Tensile Strength, Final LD.

Size Area

Strain, fu2 Elon,,.

No.

(ins)(ksi)(

peret) ps

(

IpS) (i) l (%f

0) (percent)

~~

~~~I

( percent) 0498 4

0.20 13.8 69.0 115%

0.25%

22.1 110.6 184%

13%

0499 5

0.31 20.0 64.5 108%

0.25%

32.8 105.6 176%

13%

0500 6

0.44 28.3 64.3 107%

0.20%

46.9 106.7 178%

17%

0501 7

0.60 37.9 63.2 105%

0.20%

61.7 l02.8 171%

16%

0502 8

0.79 50.9 64.4-107%

0.24%

85.0 107.6 179%

19%

0503 9

1.00 66.8 66.8 111%

0.25%

110.9 110.9 185%

17%

0593 10 1.27 87.0 68.5 114%

0.25%

131.6 103.6 173%

20%

0681 10 1.27 84.0 66.1 110%

0.24%

134.8 106.1 177%

16%

0682a 10 1.27 84.0 66.1 110%

0.24%

134.9 106.2 177%

15%

0637 11 1.56 98.0 62.8 105%

0.24%

158.0 101.3 169%.

16%

0595 14 2.25 147.0 65.3 109%

0.25%

219.0 97.3 162%

21%Vo Note a: Test No. 0593 is the control bar for No. 10 compression test Nos. 0621 to 0625, and test Nos. 0681 and 0682 are both control bars for No. I 0 cvclic test Nos. 0683 to 0687 and also No. 10 monotonic test Nos. 0688 to 0692.

(

Wiss, Janney, Elstner Associates, Inc.

TABLE 3 - COMPRESSION TESTS ON L-SERIES MBT COUPLER SPECIMENS Test Bar Bar Peak Load Final Result I.D.

Size Area (kiPS) (ksi) l (%fO)

No.

(in 0537 4

0.20 18.3 91.7 153%

No failure 0538 4

0.20 18.4 92.1 153%

No failure 0539 4

0.20 17.2 85.9 143%

Bar Buckled 0540 4

0.20 18.1 90.4 151%

No failure 0541 4

0.20 18.1 90.4 151%

No failure 0588 5

0.31 28.3 91.3 152%

No failure 0589 5

0.31 28.3 91.3 152%

No failure 0590 5

0.31 27.5 88.8 148%

Bar Buckled 0591 5

0.31 27.4 88.4 147%

Bar Buckled 0592 5

0.31 26.0 83.7 140%

Bar Buckled 0558 6

0.44 41.6 94.5 158%

No failure 0559 6

0.44 40.6 92.3 154%

No failure 0560 6

0.44 40.2 91.4 152%

No failure 0561 6

0.44 40.6 92.3 154%

No failure 0562 6

0.44 40.6 92.3 154%

No failure 0563 7

0.60 54.1 90.2 150%

No failure 0564 7

0.60

54.

90.3 151%

No failure 0565 7

0.60 55.0 91.7 153%

No failure 0566 7

0.60 55.1 91.8 153%

No failure 0567 7

0.60 53.5 89.2 149%

Bar Buckled 0568 8

0.79 71.3 90.3 150%

No failure 0569 8

0.79 71.8 90.9 151%

No failure 0570 8

0.79 71.9 91.0 152%

No failure 0571 8

0.79 72.1 91.3 152%

No failure 0572 8

0.79 71.7 90.8 151%

No failure 0573 9

1.00 91.6 91.6 153%

No failure 0574 9

1.00 91.7 91.7 153%

No failure 0575 9

1.00 92.5 92.5 154%

No failure 0576 9

1.00 91.6 91.6 153%

No failure 0577 9

1.00 92.3 92.3 154%

No failure 0621 10 1.27 115.4 90.9 151%

No failure 0622 10 1.27 115.8 91.2 152%

No failure 0623 10 1.27 116.4 91.7 153%

No failure 0624 10 1.27 115.5 90.9 152%

No failure 0625 10 1.27 115.7 91.1 I 152%

No failure 0643 11 1.56 143.5 92.0 153%

No failure 0644 11 1.56 142.7 91.5 152%

Nofailure

.0645

.11. l156. 142.5 91.3

-.152%.;.NDnfailure 0646 11 1.56 142.1 91.1 152%

No failure 0647 11 1.56 141.7 90.8 151%

No failure 0616 14 2.25 204.4 90.8 151%

No failure 0617 14 2.25 204.3 90.8 151%

No failure 0618 14 2.25 204.1 90.7 151%

No failure 0619 14 2.25 203.7 90.5 151%

No failure 0620 14 2.25 204.61 90.9 152%

No failure r

Wiss, Janney, Elstner Associates, Inc.

TABLE 4 - AC133 CYCLIC TESTS ON L-SERIES MBT COUPLER SPECIMENS Test Bar Bar Cyclic Load Levels Cycles Tensile Strength Final P it I.D. No. Size Area (Stages 1, 2, 3)

Applied (Stage 4)

(in')

P.in l

l Pmazi 1 PmA%3 nl n2 fn3 (kips)l (ksi)l (%fr60)

(kis Ips)

(ips)

(kips) 0532 4

0.20

-6.0 11.4 12.3 13.6 20 4

2 20.9 104.3 174%

Bar Break 0533 4

0.20

-6.0 11.4 13.4 15.2 20 4

4 21.6 108.2 180%

Bar Break 0534 4

0.20

-6.0 11.4 12.3 13.7 20 4

4 21.1 105.4 176%

Bar Break 053 5 4

0.20

-6.0 11.4 12.5 14.2 20 4

4 21.1 105.4 176%

Bar Break 0536 4

0.20

-6.0 11.4 12.0 13.7 20 4

4 20.7 103.4 172%

Bar Break Average 21.1 105.3 176%

0527 5

0.31

-9.3 17.7 18.7 21.7 20 4

4 32.5 104.8 175%

Bar Break 0528 5

0.11

-9.3 17.7 19.7 21.9 20 4

4 32.6 105.1 175%

Bar Break 0529 5

0.31

-9.3 17.7 20.1 22.7 20 4

4 32.8 105.7 176%

Bar Break 0530 5

0.31

-93 17.7 19.7 21.7 20 4

4 32.6 105.2 175%

Bar Break 0531 5

0.31

-9.3 17.7 19.5 21.7 20 4

4 32.5 104.7 175%

Bar Break Average 32.6 105.1 175%

0543 6

0.44

-13.2 25.1 28.0 30.4 20 4

4 47.3 107.5 179%

Bar Break 0544 6

0.44

-13.2 25.1 27.3 29.7 20 4

4 47.1 107.0 178%

Bar Break 0545 6

0.44

-13.2 25.1 27.8 30.2 20 4

4 47.2 107.3 179%

Bar Break 0546 6

0.44

-13.2 25.1 27.5 30.0 20 4

4 47.0 106.9 178%

Bar Break 0547 6

0.44

-13.2 25.1 27.8 30.0 20 4

4 47.2 107.2

'179%

Bar Break Average s.;.< -~

47.2 107.21 179%

0548 7

0.60

-18.0 34.21 35.51 38.9 20 4

4 60.1 100.2 167%

Pullout 0549 7

0.60

-18.0 j 34.2 35.8 39.0 20 4

4 60.9 10l.5 169%

Pullout 0550 7

0.60

-18.0 l 34.2 36.0 39.5 20 4

4 61.3 102.1 170%

AtBc 0551 7

0.60

-18.0 J 34.2

37. 1 41.3 20 4

4 61.2 101.9 170%

Pullout 0552 7

0.60

-18.0 f 34.2 37.3 40.9 20 4

4 60.5 100.9 168%

Pullout

Average, 60.8 101.3 169%

05533 8

0.79

-23.7 45.0 49.4 55.8 20 4

4 84.5 106.9 178%

Pullout 0554 8

0.79

-23.7 45.0 49.4 56.9 20 4

4 81.7 1 03.4 172%

Pullout 0555 8

0.79

-23.7 45.0 50.2 57.5 20 4

4 84.1 106.5 177%

Pullout 0556 8

0.79

-23.7 45.0 49.7 56.9 20 4

4 82.6 104.6 174%

Pullout 0557 8

0.79

-23.7 45.0 49.6 57.1 20 4

4 82.6 104.6 174%

Pullout Average

- 3o k 83.1 105.2 175%

0522 9

1.00

-30.0 57.0 66.0 76.0 20 4

4 110.1 110.1.

184%

Pullout 0523 9

1.00

-30.0 57.0 65.7 74.0 20 4

4 110.0 110.0 183%

Pullout 0524 9

1.00

-30.0 57.0 65.7 75.6 20 4

4 108.1 108.1 180%

AtBolt 0525 9

1.00

-30.0 57.0 65.7 75.8 20 4

4 109.8 109.8 183%

Pullout 0526 9

1.00

-30.0 57.0 65.0 74.4 20 4

4 109.9 109.9 183%

Pullout Average 1

109.6 109.6 183%

0683 0684 0685 0686 0687 Averaze 10 10 10 10 10 1.27-1.27 1.27 1.27

-38.1

-38.1

-38.1 72.4 72.4 72.4

-38.1 72.4

-38.1 72.4

-82 82.7 82.5 82.3 82.3 92.9 94.1 93.3 92.1 92.1 20 20 20 20 20 4

4 4

4 4

4 4.

4 4

4

.127.1 117.0 129.6 129.0 124.0 125.3 1.00-1 92.1 102.0 101.6 97.6 98.7

-.167%

154%

170%

169%

163%

164%

At Bolt At Bolt Pullout Pullout Pullout f

Wiss, Janney, Elstner Associates, Inc.

TABLE 4 (CONCLUDED)- AC133 CYCLIC TESTS ON L-SERIES MBT COUPLER SPECIMENS

'I A Test Bar Bar Cyclic Load Levels Cycles Tensile Strength Final Resul.

ID. No. Size Area (Stages 1, 2,3)

Applied (Sta-e 4)

(in2)

Pmin l Pm211 Pmax2 Pma3 n1 n, 1 n3 (kips)J (ksi) l (%f,-a)

__ (kips)J I(kips)

(kips)

(kips)

I I

I 0638 11 1.56

-46.8 88.9 92.8 104.8 20 4

4 148.4 95.1 159%

At Bolt 0639 1 1 1.56

-46.8 88.9 95.4 108.8 20

4.

4 154.3 98.9 165%

At Bolt 0640 11 1.56

-46.8 88.9 95.4 108.8 20 4

4 149.3 95.7 160%

At 2nd Bolt 0641 I I 1.56

-46.8 88.9 95.4 108.8 20 4

4 159.9 102.5 171%

Bar Break 0642 11 1.56

-46.8 88.9 94.4 106.6 20 4

4 154.8 99.2 165%

At Bolt Average

______1533 98.3 164%

0604 14 2.25

-67.5 128.3 132.7 153.3 20 4

4 211.4 94.0 157%

Pullout 0605 14 2.25

-67.5 128.3 137.3 153.3 20 4

4 219.1 97.4 162%

Pullout 0606 14 2.25

-67.5 128.3 13 7.3 153.0 20 4

4 217.8 96.8 161%

Pullout 0607 14 2.25

-67.5 128.3 133.7 153.6 20 4

4 216.2 96.1 160%

Pullout 0608 14 2.25

-67.5 128.3 133.7 151.9 20 4

4 214.4 95.3 159%

Bar Break Average 215.8 95.9 160%

Note: For size No. 14 specimens, strength acceptance criteria is 92.5 ksi or 154%f,; as summarized in Table 5.

... ss, Janney, Elstner Associates, Inc.

TABLE 5 - SPLICE ACCEPTANCE CRITE RIA rData I TiarRirptinIh I

Specirfieu ks ks 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 I 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 90.0 Actual fyi f'u ksi) (ksi) 69.0 110.6 64.5 105.6 64.3 106.7 63.2 102.8 64.4 107.6 66.8 110.9 68.5 103.6 66.1 106.1 66.1 106.2 62.8 101.3 65.3 97.3 ICBO ES AC133 (1998) / UBC (1997)

Coiiipressionl 125%fy

_(ksi) 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 96.0 92.5

.I.-.------.:

92.5 I Yve A Seisniic snlice Sirpnothi CMi.Prn

-r 160%fyo 9 5%fu,

-(kI()

I sj) 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 105.1 100.4 101.3 97.7 102.2 105.4 98.4 100.8 100.9 96.2 92.5 Lesser of

_(isi) 96;s0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 96.0 92.0 ACI 318-99 Clapter 21 Conlpression Tension 125%fy.

I0%fuB (ksi) ksi) 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 75.0 90.0 fy. = Specified yield strength fu = Specified tensile strength fy = Acttial yield strength

f. = Actual tensile strengtl Bar Bar Size Area (in')

4 5

6 7

8 9

10.

10 10 It 14.

0.20 0.31 0.44 0.60 0.79 1.00 1.27 1.27 1.27 1.56 2.25 915 A" I

i r

I --

I I

I I

Bar Teiisiori I

._}t

Wiss, Janney, Elstner Associates, Inc.

TABLE 6 - MONOTONIC TENSION TESTS ON L-SERIES MBT COUPLERS Test Bar Bar Tensile Strength iFinal Result I.D. No. Size Area (kips)) (ksi)

(%f...ao) 0688 10 1.27 129.1 101.7 169%

At Bolt 0689 10 1.27 125.9 99.1 165%

Pullout 0690 10 1.27 133.3 105.0 175%

At Bolt 0691 10 1.27 127.0 100.0 167%

Pullout 0692 10 1.27 129.2 101.7 170%

Pullout Average 128.9 101.5 169%

I

Topical Report 24370-TR-C-001 -A Appendix E Tabulated Mechanical Test Results and Example Raw Data Bechtel/lNEEL Tests December 2001 Page 77 of 88

Topical Report 24370-TR-C-001-A Table 1 - Tensile Properties for #6 Rebar Heat ID: 589812899 Specimen HOF Yield UTS Ef E

ID (ksi)

(ksi)

(%)

(Msi)

U6-2 67.7 106.9 14.0 28.7 U6-5 66.8 106.6 13.5 27.4 U6-9 67.0 107.0 12.9 28.1 U6-11 67.6 107.8 14.2 28.6 U6-12 69.9 109.7 10.6 27.3 U6-14 67.9 107.9 12.9 28.3 U6-18 67.3 106.5 14.1 26.2 Averages P

6.-

l 13.2 27.8 Table 2 - Tensile Properties for #8 Rebar (Heat ID: 589813260)

Specimen HOF Yield UTS Ef E

ID (ksi)

(ksi)

(%)

(Msi)

U8-11 72.5 110.3 U8-12 72.4 108.8 U8-13 71.7 109.5 U8-14 73.0 111.0 U8-16 72.8 110.2 U8-18 72.5 110.4 U8-20 73.0

.110.6 Averages N

72.4 b 1i)

NgI 12.9 11.2 12.2 9.8 11.0 11.7 11.5 11.5 30.1 28.7 29.3 28.8 29.1 29.2 29.1 29.2 Page 78 of 88

Topical Report 24370-TR-C-001-A Table 3 - Splice Specimen Strength Test Results Failure Final Type)

Strain (%)

NAk 3.8 15.2 14.4 15.2 4.9 4.1 4.2 13.1 2.7 4.6 13.0 4.4 2.7 10.8 12.3 3.8 9.8 11.5 19.1 15.4 11.0 11.6 2.7 4.1 11.5 11.3 UTS (ksi) 107.9 108.0 98.9 106.4 107.3 107.8 107.6 106.9 103.2 107.6 107.3 105.6 103.4 105.8 104.0 108.0 103.7 106.3 106.1 107.6 106.0 105.0 103.1 107.8 105.1 107.9 Specimen ID (#8)

Average S8-01 S8-02 S8-03.

S8-04 S8-05 S8-06 S8-07 S8-08 S8-09 S8-10 S8-11 S8-12 S8-13 S8-14 S8-15 S8-16 S8-17 S8-18 S8-19 S8-20 S8-21 S8-22 S8-23 S8-24 S8-25 S8-26 Failure Final Type Strain (%)

NAb 0

T 0

0 P

T T

T 0

T T

0 T

T T

T T

T T

T T

T T

3.7 1.4 4.9 3.7 10.4 4.9 4.4 3.6 3.6 1.8 2.1 3.8 3.4 3.2 3.7 4.0 2.1 4.5 4.0 4.6 3.5 4.3 3.8 3.3 10.4 4.2 J B = bar break outside coupler but within extensometer gage length, 0 = bar break outside coupler and outside extensometer gage length, T = bar break at tip of first lock bolt, P = bar pulled out of coupler without breaking, * = bar break in interior of coupler k The final strain is dependent on several factors, including mode of failure. An average value for all tests has no significance. For example, in a pull-out failure the final strain is determined by the length of time the operator chooses to continue the test once pull-out is observed.

Page 79 of 88 Specimen ID (#6)

Average S6-01 S6-02 S6-03 S6-04 S6-05 S6-06 S6-07 S6-08 S6-09 S6-10 S6-11 S6-12 S6-13 S6-14 S6-15

.S6-16 S6-17 S6-18 S6-19 S6-20 S6-21 S6-22 S6-23 S6-24 S6-25 S6-26 UTS (ksi) 109.6 96.8 109.8 110.1 108.4 109.7 110.4 109.4 110.5 102.1 106.0 108.0 110.5 110.1 106.7 111.0 104.5 109.3 109.4 110.1 109.7 109.4

.109.8 108.5 110.0 109.9

Topical Report 24370-TR-C-001-A Specimen Failure Final UTS Specimen Failure Final UTS ID (#6)

Typei Strain (%)

(ksi)

ID (#8)

Type Strain (%)

(ksi)

Average NAk Average NA' S6-27 P

12.2 106.4 S8-27

• P 7.0 109.7 S6-28 0

3.9 107.8 S8-28 T

4.1 109.0 S6-29 B

4.8 107.0 S8-29 0

3.8 109.7 S6-30 0

4.3 107.6 S8-30 0

3.5 110.3 S6-31 0

4.4 107.4 S8-31 T

3.9 110.5 S6-32 T

3.8 107.2 S8-32 T

2.5 109.0 S6-33 T

2.9 105.7 S8-33 0

4.4 110.3 S6-34 P

12.6 105.7 S8-34 T

3.5 109.7 S6-35 T

4.4 107.2 S8-35 T

2.5 105.4 S6-36 T

2.8 104.2 S8-36 T

4.1 110.5 S6-37 0

3.8 107.2 S8-37 5.0 110.2 S6-38 P

11.5 107.4 S8-38 P

10.3 109.9 S6-39 P

12.9 107.0 S8-39 T

3.9 111.2 S6-40 P

11.3 106.3 S8-40 P

10.2 113.6 Table 4-Results of Residual Strength Tests on Load-Cycled Specimens Specimen Failure Final UTS Specimen Failure Final UTS ID (#6)

Type Strain (%)

(ksi)

ID (#8)

Type Strain (%)

(ksi)

Average NA 104.9 Average NA 106.7 C6-2 P

3.8 104.3 C8-15 106.6 C6-3 P

3.7 106.3 C8-21 106.0 C6-7 P

5.0 106.2 C8-27 107.6 C6-14 P

7.0 103.3 C6-15 P

3.7 104.5 Page 80 of 88

Topical Report 24370-TR-C-001-A 120 100 80 60

'cn 40 20 0

0 4

8 12 16 Engineering Strain (%/I)

Figure 1 - Representative Stress-Strain Curve from #6 Rebar Material 120 100 80 60 40 20 0

0 4

8 12 16 Engineering Strain (%)

Figure 2 - Representative Stress-Strain Curve from #8 Rebar Material Page 81 of 88

'A C

cj Ib

Topical Report 24370-TR-C-001-A 40 30 M 20 10 0

0.004 0.006 Displacement across Coupler (in.)

0.012 Figure 3 - Data Curves Showing Load-Unload Cycle to Assess Bar Slip in Couplers f

Page 82 of 88 Found knife edges on extensometer to be loose following the test I

I

Topical Report 24370-TR-C-001-A 0.5 Crosshead Displacement (in.)

1 1.5 2

4 1

2 3

,i Strain (%)

Figure 4-Representative Stress, Strain, and Displacement Data from a Coupler Assembly Strength Test Page 83 of 88 0

120 100 80 um 60

-cn 40 20 0

0

Topical Report 24370-TR-C-OO -A 0.000 0.005 0.010 0.015 0.020 Displacement across Coupler (in.)

0.025 Figure 5 - Cyclic Stress-Displacement History for a Typical Test f

Page 84 of 88 60 50 40 co U,

Topical Report 24370-TR-C-001-A Appendix F No Significant Hazards Consideration Determination DESCRIPTION OF THE PROPOSED CHANGE The four steam generators of the Sequoyah Nuclear Plant Unit 1 will be replaced during the spring of 2003. To support the replacement of the old steam generators (OSGs) with the replacement steam generators (RSGs), temporary construction openings will be cut through the concrete shield building, steel containment vessel, and concrete steam generator compartment roofs. Restoration of the temporary concrete construction openings may be accomplished by splicing new reinforcing steel (rebar) to the existing rebar and pouring new concrete.

Original construction at the Sequoyah plant used lap splices to join rebar. Generally, Cadweld splices have been used in the nuclear industry when safety-related concrete repairs involve removal and replacement of a portion of the rebar. The Cadweld splice has become the standard mechanical rebar splice for the nuclear industry, and its use is supported by years of successful installation, industry codes and standards, and regulatory acceptance. However, the Sequoyah plant proposes to use the Bar-Lock coupler system to restore the temporary concrete construction openings following installation of the new Unit 1 steam generators.

To support use of the Bar-Lock coupler system at the Sequoyah plant, a qualification testing program was undertaken. Details of this testing program and the test results are documented in Topical Report 24370-TR-C-001.

II.

REASON FOR THE PROPOSED CHANGE The Bar-Lock coupler system provides a number of installation advantages over other mechanical splice concepts that make it a candidate for the concrete restoration activities associated with the Sequoyah steam generator replacement. The Bar-Lock coupler system has specified mechanical properties that meet ASME/ACI criteria for mechanical rebar splices.

Ill.

SAFETY ANALYSIS Mechanical splices for reinforcing steel used in nuclear safety-related concrqte structures are subject to the stringent requirements of ASME Section III, Division 2/ACI-359 and ACI-318, which includes the requirement that the splice develop 125% of the minimum yield strength of the reinforcing bar. In order to demonstrate that the Bar-Lock coupler can meet these requirements, a qualification program has been performed. The qualification program included development of a testing program, performance of physical tests, and analysis and interpretation of the test results.

The Bar-Lock coupler qualification testing program was carried out on two representative sizes - #6 and #8 - of their L-Series couplers. A total of 160 coupler assemblies were tested. Fourteen pieces of rebar were tested to determine the actual, or measured, mechanical properties of the two heats of bar material used to fabricate the test specimens.

Page 85 of 88

Topical Report 24370-TR-C-001-A The tensile strength tests on each of the 80 samples exceeded the two ASME requirements by a large margin. Statistical analyses of the test results determined several important performance indicators. Based on the observed data distribution, the probability of a coupler assembly (in size #6 or #8) failing to meet the minimum qualification strength criterion is less than 3 in 100,000.

There was some variation in strength between the two heats of rebar used in the strength tests. Comparing and correlating these results show that Bar-Lock L-Series coupler splices can be expected to achieve a tensile strength greater than 96% of the actual bar strength. While there are not enough different combinations of bar material and coupler size data, the combined test results from this program appear similar when normalized by the actual bar strength. So, it is likely these test results are representative of the performance of other sizes of Bar-Lock L-Series couplers. In other words, the mechanical design of the Bar-Lock L-Series coupler is such that spliced joints can be expected to develop over 96% of the actual bar strength.

Slip tests performed on selected specimens of both sizes showed a solid mechanical connection between the coupler and the rebar. There was no tendency for the rebar to move within the coupler prior to developing full splice strength. This was expected since the conical-tipped lock bolts physically embed into the bar material providing a physical shear force transfer from bar to coupler.

Each of the 80 splice specimens that underwent the cyclic loading durability test passed the 100-cycle test, with no obvious physical degradation of the spliced joint. To provide an additional degree of assurance of adequate cyclic durability, selected specimens received 1000 cycles of loading, again with no noticeable physical degradation. Some of the specimens that passed the 100 cycle test were subsequently tested by monotonic loading to failure. The resultant measured strengths were essentially the same as the virgin strength test specimens (no cyclic loading applied). These results suggest that the design of the Bar-Lock coupler is essentially insensitive to cyclic loading to levels below 90% of the minimum bar yield strength.

The results of these tests, compared to the ASME splice system qualification requirements, indicate that the Bar-Lock coupler design for rebar splicing is entirely adequate from a strength point of view for use in nuclear safety-related construction.

The additional quantity of couplers tested provides higher confidence that the couplers do meet, and indeed far exceed, those ASME-specified requirements.

IV.

NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION f

TVA has concluded that operation of SQN Unit 1, in accordance with the proposed use of Bar-Lock L-Series couplers in the restoration of the temporary concrete construction openings, does not involve a significant hazards consideration. TVA's conclusion is based on its evaluation, in accordance with 10 CFR 50.91 (a)(1), of the three standards set forth in 10 CFR 50.92(c).

A.

The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

No changes in event classification as discussed in UFSAR Chapter 15 will occur due to use of the Bar-Lock couplers.

Page 86 of 88

Topical Report 24370-TR-C-001-A The restoration of the temporary concrete construction openings in the shield building and steam generator compartments may utilize Bar-Lock couplers to splice new rebar to the existing rebar. These structures limit the release of radioactivity following an accident, direct the steam released due to a pipe break inside containment through the ice condenser, and protect the SSCs inside containment from external events. The accidents of interest here are those that rely on the shield building to limit the release of radioactivity to the environment, those that rely on the divider barrier inside containment to direct the steam released due to a pipe break through the ice condenser, and those that result from some external event. The design of the shield building and steam generator compartments is such that they are not postulated to fail and initiate an accident described in the UFSAR.

The Bar-Lock coupler qualification tests detailed in Topical Report 24370-TR-C-001 demonstrated that the Bar-Lock coupler meets the ASME strength requirements and is, therefore, acceptable for use in nuclear safety-related applications. Based on these test results, it is concluded that use of the Bar-Lock couplers in restoring the temporary concrete construction openings will not reduce the structural capability of the repaired structures. They will, therefore, continue to perform their functions as described in the Sequoyah UFSAR.

Therefore, the proposed use of the Bar-Lock couplers will not significantly increase the probability or consequences of an accident previously evaluated.

B.

The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

As indicated in the response to Question IV.A above, the design of the shield building and steam generator compartments is such that they are not postulated to fail and initiate an accident described in the UFSAR. The Bar-Lock couplers are passive devices and as such will not initiate or cause an accident.

The restoration of the temporary concrete construction openings in the shield building and steam generator compartments may utilize Bar-Lock couplers to splice new rebar to the existing rebar. The Bar-Lock coupler qualification tests detailed in Topical Report 24370-TR-C-001 demonstrated that the Bar-Lock coupler meets the ASME strength requirements and is, therefore, acceptable for use in nuclear safety-related applications. Based on these test results, it is concluded that use of the Bar-Lock couplers in restoring the temporary concrete construction openings will not reduce the structural capability of the repaired structures. This will restore these structures to their design capabilit'. The shield building and steam generator compartments will, therefore, continue to perform their functions as described in the Sequoyah UFSAR.

Therefore, the possibility of a new or different accident situation occurring as a result of this condition is not created.

C.

The proposed amendment does not involve a significant reduction in a margin of safety.

As indicated in Sections 3.8.1.2 and 3.8.3.2 of the Sequoyah UFSAR, the structural design of the shield building and interior concrete structures is in Page 87 of 88

Topical Report 24370-TR-C-001 -A compliance with the American Concrete Institute (ACI) 318-63 building code working stress design requirements. The reinforcing steel conforms to the requirements of ASTM A 615, Grade 60. UFSAR Section 3.8.1.1 states that reinforcing bars were lap spliced in accordance with ACI 318-63 requirements for Strength Design.

The restoration of the temporary concrete construction openings in the shield building and steam generator compartments may utilize Bar-Lock couplers to splice new rebar to the existing rebar. The restoration of the construction openings, including use of the Bar-Lock couplers, will conform to the requirements of ACI 318. Therefore, following completion of the restoration of these structures, they will still comply with ACI 318 requirements.

In addition to conforming to ACI 318 requirements, the Bar-Lock coupler qualification tests detailed in Topical Report 24370-TR-C-001 demonstrated that the Bar-Lock coupler meets the ASME strength requirements.

Therefore, a significant reduction in the margin to safety is not created by this modification.

V.

ENVIRONMENTAL IMPACT CONSIDERATION The proposed change does not involve a significant hazards consideration, a significant change in the types of or significant increase in the amounts of any effluents that may be released offsite, or a significant increase in individual or cumulative occupational radiation exposure.

Therefore, the proposed change meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), an environmental assessment of the proposed change is not required.

Page 88 of 88

Topical Report 24370-TR-C-OO1-A Appendix G Responses to NRC Request for Additional Information f

Page 88a of 88

S64 021210 800 Tennessee Valley Authoty, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 December 10, 2002 10 CFR 50.4 U.S. Nuclear Regulatory Commission ATTN:

Document Control Desk Washington, D. C. 20555 Gentlemen:

In the Matter of

)

Docket Nos. 50-327 Tennessee Valley Authority SEQUOYAH NUCLEAR PLANT (SQN)

STEAM GENERATOR REPLACEMENT PROJECT -

TOPICAL REPORT NO. 24370-TR-C-001, "ALTERNATE REBAR SPLICE -

BAR-LOCK MECHANICAL SPLICES,"

RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION

Reference:

NRC letter to TVA-dated December 4,

2002, "Sequoyah Nuclear Plant, Units 1 and 2 -

Request for Additional Information Concerning Unit 1 Steam Generator Replacement Topical Reports and Associated Technical Specification Amendment (TAC NOS. MB5370, MB5371, MB5387)"

The purpose of this submittal is to provide additional information.in response to the staff's referenced letter.

Based on discussion with the staff during a meeting etween TVA, Bechtel, and NRC on October 24, 2002, TVA under6tands that the additional information will allow the staff to complete their review of he subject topical report.

The approval of the topical report supports SQN's Unit 1 steam generator replacement outage that is scheduled to begin in March 2003.

U.S. Nuclear Regulatory Commission Page 2 December 10, 2002 Enclosed is the additional information that supports Topical Report No. 24370-TR-C-001.

The additional information requested for Topical Report Nos. 24370-TR-C-002 and 24370-TR-C-003 will be submitted by separate letters.

This letter is being sent in accordance with NRC RIS 2001-05.

There are no commitments contained in this letter.

If you have any questions about this change, please telephone me at (423) 843-7170 or J. D. Smith at (423) 843-6672.

Sincerely, original signed by Pedro Salas Licensing and Industry Affairs Manager Enclosure

U.S. Nuclear Regulatory Commission Page 3 December 10, 2002 JDS:DVG:SJM Enclosure cc (Enclosure):

R. J. Adney, LP 6A-C J. L. Beasley, OPS 4A-SQN M. J. Burzynski, BR 4X-C M. H. Dunn, ET 1A-K D. L. Koehl, POB 2B-SQN J. E. Maddox, LP 6A-C NSRB Support, LP 5M-C R. T. Purcell, OPS 4A-SQN J. A. Scalice, LP 6A-C K. W. Singer, LP 6A-C WBN Site Licensing Files, ADM 1L-WBN EDMS, WTC A-K

.:License/steam generator replacement/topical reports/RAI response for ar-Lock.doc IT

ENCLOSURE TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNIT 1 DOCKET NO. 327 ADDITIONAL INFORMATION FOR TOPICAL REPORT NO. 24370-TR-C-001, "ALTERNATE REBAR SPLICE -

BAR-LOCK MECHANICAL SPLICE" NRC Question No. 1 Provide a copy of the Bechtel/Idaho National Engineering and Environmental Laboratory (INEEL) test report for the Bar-Lock Mechanical Splices.

The report should include information on who performed the.splice tests, their qualifications, and how the tests were performed.

TVA Response A copy of the Bar-Lock test report prepared by INEEL is provided as Attachment 1. This report summarizes the test plan, results of rebar material testing, couplers tested, and results of the tensile and cyclic testing of the couplers.

Based on the INEEL test plan, Bechtel developed a specification that defined the testing requirements.

These test requirements were incorporated into the work plan and inspection record (WPIR) for controlling the Satec test machine setup, preparation of the Bar-Lock test specimens, and performance of the testing.

Bechtel personnel performed testing of the Bar-Lock couplers at the SQN site using a Satec 600VTL test machine.

These personnel were trained by Instron/Satec in the use of the test machine.

Calibration of the test machine was performed prior to its use and after completion of the Bar-Lock testing.

Bechtel Quality Control (QC) personnel reviewed the calibration documentation for acceptability.

Rebar and coupler test specimens were prepared in accordance with Bar-Lock guidelines and the requirements of the Bechtel specification by personnel trained either by a Bar-Lock representative or by Bechtel personnel certified by Bar-Lock.

TVA and Bechtel Quality Assurance (QA) QC personnel periodically monitored the preparation and testing of the test specimens.

E-1

An INEEL representative was present during the initial setup of the Satec machine, programming of the test software, and witnessed the coupler testing.

NRC Question No. 2 Describe TVA's involvement, if any, in the Bechtel/INEEL test program.

TVA Response TVA was heavily involved in the Bechtel/INEEL test program

• TVA reviewed and approved the following specifications, procedures and test plans associated with the procurement, testing, and installation of the Bar-Lock couplers.

24370-C-311, "Technical Specification for Purchase of Bar-Lock Couplers" 24370-C-312, "Technical Specification for Installation of Bar-Lock Rebar Splices" 24370-C-602, "Technical Specification for Qualification Testing of Bar-Lock Mechanical Rebar Splices" Construction Procedure CP-C-13, "Bar-Lock Rebar Splices" "Test Program Plan for Qualification of Bar-Lock Coupler System for Use in Nuclear Safety-Related Applications,"

prepared by Idaho National Engineering and Environmental Laboratory

• TVA Civil Engineers attended the vendor training session conducted at SQN on August 21, 2001.

• TVA Engineering and QA personnel witnessed the preparation of several test assemblies on August 21-22, 2001.

• TVA Engineering and QA personnel also witnessed testing of several specimens throughout the duration of the test program from October 11, 2001 to October 19, 2001.

• TVA reviewed and approved the Mechanical Testing Program and Performance Analysis, prepared by INEEL.

E-2

NRC Question No. 3 Clarify whether TVA has evaluated and determined that the Quality Assurance (QA) programs of the reinforcing bar supplier (Consolidated Power Supply), the reinforcing bar fabricator (Birmingham Steel Corporation), the manufacturer of the Bar-Lock coupler (including lockshear bolt, and serrated rail), and the contractors who performed the tests (Bechtel/INEEL), meet the Title 10, Code of Federal Regulations (10 CFR) Part 50, Appendix B requirements? Provide the results of TVA's evaluations of theses QA programs.

TVA Response TVA has reviewed and approved Bechtel's Sequoyah Steam Generator Replacement (SGR) Project Nuclear Quality Assurance Manual.

The policies in this manual correspond to each of the 18 criteria of 10 CFR 50, Appendix B and meet the requirements of ANSI N45.2 and N45.2 series standards and QA-related NRC regulatory guides.

Bechtel, in its role as a contractor to TVA, imposed the applicable 10 CFR 50 Appendix B requirements along with the technical and document submittal requirements on the subcontractors involved in the material supply, fabrication, and testing of the rebar and Bar-Lock couplers.

Bechtel reviewed the quality programs for the rebar supplier (Consolidated Power Supply), the manufacturer of the Bar-Lock coupler (Valley Machining), and INEEL, and where appropriate, required changes to these programs to bring them into compliance with the requirements of 10 CFR 50, Appendix B. Bechtel specifications required their subcontractors to extend the specification requirements to their contractors.

NRC Question No. 4 On page 10 the report states that Bechtel witnessed and verified implementation of Bar-Lock's manufacturing quality control processes and procedures for compliance with the applicable provisions of American National Standards Institute/ Ame'rican Society of Mechanical Engineers (ANSI/ASME) N45.2.

Identify and submit for staff's review the applicable provisions of ANSI/ASME N45.2 that were considered.

Discuss how the Bar-Lock's manufacturing quality control processes and procedures comply with the 10 CFR Part 50, Appendix B requirements.

E-3

TVA Response The provisions/requirements of ANSI/ASME N45.2-77 that were considered applicable to the manufacturer of the Bar-Lock couplers (Valley Machining) are:

2.

Quality Assurance Program

3. Organization

5.

Procurement Document Control

6.

Instructions, Procedures, and Drawings

7.

Document Control

8.

Control of Purchased Material, Equipment, and Services

9. Identification and Control of Materials, Parts, and Components

10.

Control. of Special Processes

11. Inspection

12. Test Control

13. Control of Measuring and Test Equipment

14. Handling, Storage, and Shipping

15. Inspection, Test, and Operating Status

16. Nonconforming Items

17. Corrective Action

18. Quality Assurance Records

19. Audits Review of the Bar-Lock manufacturing processes along with the provisions of the specification for the purchase of the Bar-Lock couplers as described below assures that the corresponding requirements of 10 CFR 50, Appendix B are also met.

A specification, written for the purchase of the Bar-Lock couplers, identified the technical requirements the Bar-Lock manufacturer was required to meet.

These requirements covered applicable codes and standards, quality, shipping, handling, storage, critical processes and parameters, and documentation.

Bechtel QA personnel performed surveillances during the manufacturing of the Bar-Lock couplers to verify that the manufacturing process was performed in a manner that was consistent with the specification.

The critical processes identified in the specification and the results of the Bechtel QA surveillances are summarized below:

a. Application of material traceability identification on bolt, tube, and saddle material The material traceability of each heat lot of material for the tubing, hex stock for bolting, and square stock for the saddles was verified by review of the mill tag affixed to each bundle of material and visual E-4

verification of the physical markings on the stock.

The material test reports were reviewed to verify material composition and strength were as required by the specification.

b. Tapping of bolt hole The drilling and tapping of bolt holes was performed in one machine operation.

The hole locations were checked initially by the machinist and by the inspector when the machine was set up.

Set up pieces were identified as such and were not included as part of the production run.

When the production run began, the finished holes were checked on a random basis by the machinist and by the roving inspector using a calibrated go/no go plug gauge.

In addition, 100 percent of the threaded holes were verified as completely drilled and tapped since each coupler is fully assembled with the bolts installed at final assembly and inspection.

This process was monitored by Bechtel QA and Bar-Lock personnel throughout the drilling and tapping process.

No deviations from the design drawing were noted.

c. Induction heating of bolt tip The induction heating process was monitored on a periodic basis by Bechtel QA personnel and by the operator and QC inspector.

Six samples were taken by the operator and verified by the QC inspector at approximately four-hour intervals during the induction hardening process.

The tested bolts all fell within the specified hardness range.

d. Fusion of saddles to tube The weld of the saddle to the tube is critical only to the extent that it needs to hold the saddles in position until the bar is inserted and the bolts set.

There is no credit taken for the weld in the ability of the coupler to withstand the required tensile and cyclic performance criteria.

The weld is tested on a random basis by the QC inspector by dropping the coupler from a height of 5 feet onto concrete.

If there is no weld failure, the weld is considered acceptable.

There were no failures noted during these tests.

e. Bolt shear testing Each shear value bolt test was witnessed by Bechtel QA personnel.

Unique heat lot numbers were assigned to E-5

each batch of bolts sent to the heat treatment facility.

After heat treating and quench, the bolts were tested at the heat treatment facility for hardness to determine the amount of time and temperature required in the draw furnace. After final treatment the bolts were again checked for hardness to verify conformance with the required hardness.

The shear testing for each lot resulted in satisfactory results.

Each bolt was stamped during the machining operation with the letters VMC to help assure that no other bolts would be co-mingled with those produced for Sequoyah.

f. Heat treatment condition of saddles After machining, the saddles were heat treated and case hardened.

Bechtel QA personnel witnessed the furnace load time and verified the furnace temperature.

Fifty-three saddles of each size were tested to verify that the required minimum case hardening depth and hardness were achieved.

The results were satisfactory.

The critical parameters identified in the specification were:

a. Length of tube

b. Inside diameter of tube

c. Outside diameter of tube

d. Number of bolts

e. Saddle location

f. Bolt spacing

g. Bolt edge distance

h. Bolt threads

i. Bolt tip hardness

j.

Diameter of bolt shear plane

k. Actual bolt break-point torque values.

The critical parameters listed above were verified by Valley Machining machine operators and QC personnel.

Bechtel QA personnel verified each of these parameters during regular monitoring throughout the manufacturing process.

All measurements were made using equipment calibrated under a controlled calibration program with standards of calibration being traceable to NIST or another nationally recognized standard.

Calibration records were reviewed by Bechtel QA personnel.

The supplier procurement documents from Bar-Lock to Valley Machining were reviewed by Bechtel QA personnel for the coupler design for nuclear safety-related applications.

In addition, the procurement documents for the tube material, hex E,-

E6

stock for bolts, and square stock for the saddles were reviewed.

Bechtel QA personnel examined a completed container of couplers for shipping preparation and container identification.

The preparation was found to comply with the requirements of ANSI N45.2.2, Level C, as required by the specification.

NRC Question No.

5 On page 11 of the report it states that, "Since the Bar-Lock couplers will be used in a nuclear safety-related application, they are subject to a commercial grade dedication program."

Describe and submit the commercial grade dedication program for staff's review.

TVA Response The TVA dedication program for procurement and use of commercial grade items in safety-related applications is based on guidelines contained in Electric Power Research Institute (EPRI) Report No.

NP-5652, "Guideline for the Utilization of Commercial Grade Items in Nuclear Safety-Related Applications."

TVA procedures require the use of one (or any combination of) the methods described in the report for dedication of commercial grade items.

Based on the nature of the Bar-Lock coupler procurement (i.e., an infrequent procurement of a specialized component), the "source verification" method described in Section 3.3 of the EPRI report was used.

Under this dedication process, a component-specific specification was developed (as discussed in the response to Question 4) which established the Codes, Standards and quality assurance requirements for fabrication of the couplers.

The specification established minimum material and tensile strength requirements based upon the safety function performed by the coupler and identified the critical processes and parameters requiring verification to ensure compliance with the established functional requirements.

To verify conformance with the requirements of the specification, source surveillance of the manufacturer's facility and fabrication activities was performed prior to and during component manufacture.

The scope of the surveillance activities verified compliance with the quality assurance and critical parameter requirements of the specification.

The results of the inspections, tests, and certifications performed during source surveillance activities were documented in a material fabrication report compiled by the manufacturer.

This documentation was reviewed by TVA as part of the component receipt inspection and was confirmed to be adequate to establish the component critical E-7

characteristics under the "source verification" dedication method outlined in EPRI Report No. NP-5652.

NRC Question No. 6 On page 12 of the report it states that the records of bolt shear test results were examined.

Describe how the bolt shear test was conducted and submit a typical bolt shear test result, including the relationship between applied shear force and recorded shear deformation of a test bolt.

TVA Response The bolt shear-torque test was conducted.

The shear-torque was tested by gripping the end of the bolt to secure it, and then torquing the bolt until the head sheared off.

The torque wrench used for the test had a memory device capable of recording shear-torque of the bolt head.

The bolts were inspected and tested to meet the Bar-Lock Bolt Specifications.

The major diameter, pitch, fit, and length were inspected and recorded.

The shear-torque (ft-lbs) value at bolt head break was also recorded.

These values were recorded for each sample set on Valley Machining Form POP-05 #3. Typical inspection and testing record sheets are provided as Attachment 2.

The shear deformation at the bolt head was not specifically tested.

Any deformation that occurs due to the shear-torque test will be localized, occurring in the shear plane of the bolt head break.

The bolt head break is located outside the active area of the coupler and would therefore have no impact on the strength, reliability, and function of the coupler.

NRC Question No. 7 The Bar-Lock coupler system relies on the clamping force generated on the rebars between the lockshear bolts and serrated rails.

Provide the magnitude of the compressive stress and force on the tip of a lockshear bolt and the strain in the bolt after the bolt installation.

Provide the stress relaxation characteristic of the lockshear bolt (relaxation is defined as the loss of its compressive stress under strain for a period of time).

Provide evidence that the clamping force generated by the lockshear bolt would not be reduced, as a result of the relaxation phenomenon, to a point that would degrade the proper function of the Bar-Lock coupler system during the life of the plant.

E-8

TVA Response The Bar-Lock bolt tips are hardened to a level that exceed the hardness of the rebar, ensuring no plastic deformation of the bolt tips.

The results of the testing performed at SQN confirmed this design, in that where the splice failure mode was rebar pull-out, the rebar had been damaged by the bolt tips, while no bolt tip failures were experienced.

Note that the splice failure occurred well after the design load was reached.

To show that the design properly accounts for the stress and strain is evidenced in the reliability of the couplers tested in this qualification process.

Stress relaxation is associated with materials within or very near their creep. temperature ranges.

For carbon and low alloy steel bolting, stress relaxation is not considered a concern at ambient temperatures.

Under these conditions the stress in the Bar-Lock coupler is not time dependent.

E-9

ATTACHMENT 1 Idaho National Engineering and Environmental Laboratory (INEEL) Test Report Al-I I

X

INEEUEXT-02-01 387 Qualification of the Bar-Lock Rebar Coupler For Use in Nuclear Safety-Related Applications:

Mechanical Testing Program and Performance Analysis W. R. Lloyd Published Dec 2001 Idaho National Engineering and Environmental Laboratory Materials Department Idaho Falls, Idaho 83415-2218 4:?

Summary Bechtel Corporation and INEEL developed and performed an independent mechanical testing and analysis program to assess the mechanical performance characteristics of the Bar-Lock L-Series rebar coupler system. A test plan that exceeded the assessment requirements given in ASME Section CC4333 was developed. To achieve high statistical confidence in measured sample parameters, e.g. ultimate strength, the number of specimens tested was increased to forty (40) from the ASME Code-required quantity of six (6). Bechtel QA/QC personnel monitored the testing program to ensure that it was performed in accordance with the requirements in Specification 24370-C-602.

Static strength tests of two sizes, #6 and #8, of Bar-Lock coupler assemblies showed that they exceeded the ASME-specified minimum strength levels by large margins. Statistical analysis of the results showed a 99.998% probability that the average strength of a group of coupler assemblies would exceed the ASME static strength requirement of 90% of the joined rebar tensile strength. Assessing the performance of individual coupler assemblies against the ASME-specified minimum strength (75 ksi for the Grade 60 rebar used in the tests) for individual assemblies showed that the average strength of an individual assembly was more than 8 standard deviations above the specified minimum. This corresponds to the probability that essentially 100% of all coupler assemblies would exceed the specified minimum strength.

Forty specimens of each of the two sizes (6L and 8L) of coupler/rebar assembly were tested to determine their cyclic loading durability. The test procedure cycled each assembly between 5 and 90% of specified minimum bar yield strength (60 ksi) 100 times. None of the specimens failed in any manner, e.g. bar break, or bar slip within the coupler.

In an effort to improve the cyclic durability performance assessment, several randomly selected specimens received additional cyclic loading. Each selected specimen had an additional 1000 loading cycles imposed. None of the specimens failed, and none of them showed signs of deterioration through excessive strain accumulation or physical defornation. This provides an empirical indication that the cyclic durability of the couplers will far exceed 100 cycles.

Further, some coupler assemblies randomly selected from those already receiving 100 loading cycles were subsequently loaded to failure monotonically (static strength test). This test determifed if the prescribed cyclic loading substantially damages the integrity or strength of the coupler splice assembly.

The eight specimens tested all achieved the same nominal strength as like specimens receiving no cyclic loading.

The BechtelENEEL test program tested and demonstrated that the mechanical properties of the L-Series Bar-Lock mechanical splices meet the existing Codes and NRC requirements and are an acceptable method of connecting reinforcing bar in nuclear power plant safety-related applications. The large quantity of couplers tested provides a higher confidence that the couplers do meet, and indeed far exceed, those ASME-specified requirements.

f

'4.

CONTENTS Sumnmary...

iii

1.

Overview

2.

Test Plan.1

3.

Reinforcing Bar Mechanical Properties Tests.I 3.1

1. 6 Re-Bar Material...........................................

.2 3.2

1. 8 Re-Bar Material

.2 3.3 Material for #8 Coupler Size Cyclic Durability Tests.3

4.

Description of Coupler Test Specimens 3

5.

Test Results 4

5.1 Tensile Test Results

.5 5.1.1 Minimum Average Tensile Strength Comparison.5 5.1.2 Minimum Tensile Strength of Individual Specimens

.6 5.1.3 Tensile Strength Performance Exceeds Requirements.

7 5.2 Cyclic Test Results

.9 5.2.1 Higher Count Cyclic Tests..........................

10 5.2.2.

Residual Strength Tests........................

10

6.

Coupler Test Program Conclusions 10 6.1 Tensile Strength 10 6.2 Mechanical Slippage in the Couplers.................................-----....-----..-------------------

r-----11 6.3 Cyclic Loading Durability 1

6.4 Overall Coupler Performance 11 s.,

FIGURES Figure 1. Representative Stress-Strain Curve from #6 Rebar Material......................................... 12 Figure 2. Representative Stress-Strain Curve from #8 Rebar Material......................................... 13 Figure 3. Bar-Lock Coupler Cutaway View Showing Internal Details......................................... 13 Figure 4. Representative Test Data from a Coupler Assembly Strength Test............................... 14 Figure 5. Data Curves Showing Load-Unload Cycle to Assess Bar Slip in Couplers.................. 15 Figure 6. Cyclic Stress-Displacement History for a Typical Test................................................. 16 Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 7.

TABLES Mechanical Properties of Rebar Used in Test Specimens................................................. 2 Bar-Lock L-Series Coupler Specifications (Sizes #6 and #8)........................................... 3 Tensile Properties for #6 Rebar (Heat ID: 589812899)..................................................... 4 Tensile Properties for #6 Rebar Heat ID: 589812899.....................................

4 Re-Bar Splice Assemblies Strength Test Results.....................................

8 Results of Residual Strength Tests on Load-Cycled Specimen Assemblies................... 10 6A,

Qualification of the Bar-Lock Rebar Coupler for Use in Nuclear Safety-Related Applications:

Mechanical Testing Program and Performance Analysis

1.

OVERVIEW Bechtel Corporation and INEEL developed and performed an independent mechanical testing and

-analysis program to assess the mechanical performance characteristics of the Bar-Lock L-Series rebar coupler system. By design, this program provided a very rigorous test of coupler design mechanical performance, using the qualification criteria of ASME Section III, Division 2, CC-4333 as a standard of reference.

The BechtelINEEL test program tested aid demonstrated that the mechanical properties of the L-Series Bar-Lock mechanical splices meet the existing Codes and NRC requirements and are an acceptable method of connecting reinforcing bar in nuclear power plant safety-related applications.

2.

TEST PLAN ASME Section CC-4333 specifies performance criteria to qualify rebar splicing devices for use in nuclear safety-related applications. While the strength specifications are moderately high, the quantity of test specimens required is relatively low. To achieve high statistical confidence in measured sample parameters, e.g. ultimate strength, a larger sample size (n) is required. To achieve the desired level of confidence that any installation of these couplers will have the requisite performance characteristics, the quantity of verification test specimens (the sample set) was increased. For the static strength assessment, the ASME Code requires six specimens be tested, and all six must pass. In this test plan, the quantity was increased to n = 40 for each size tested. For the cyclic durability test, the ASME Code requires three specimens to survive the 100-cycle test. This was increased to n = 40 for each size. Increasing the statistical sample size from six or three to 40 allows a great improvement in the confidence levels (especially for the binomial distribution of the cyclic test) associated with lower bound strength and cyclic durability requirements specified in the Code.

The Bar-Lock testing was monitored by Bechtel QAIQC personnel to ensure that it was performed in accordance with the requirements in Specification 24370-C-602.

3.

REINFORCING BAR MECHANICAL PROPERTIES TESTS Mechanical properties for the rebar material used in these tests were determined in accordance with project test procedures, incorporating relevant American Society for Testing and Materials (ASTM) test standards and procedures (ASTM Designation A 370-96, Standard Test Methods and Definitions for Mechanical Testing of Steel Products; and ASTM Designation E 8-99, Standard Test Methods for Tension Testing of Metallic Materials). All mechanical properties tests were performed on the same universal test machine, using the same measurement transducers. The same test machine, load cell, and extensometer were used in all of the coupler assembly tests as well. Bechtel Quality Assurance Department retains all calibration certification and records for this equipment and these devices.

c-J IJ

The reinforcing bar used in the Bar-Lock coupler testing program was ASTM A6 15 Grade 60 material in

1. 6 ( 4 in. nominal diameter) and #8 (1 in. nominal diameter) sizes. Consolidated Power Supply, the vendor of the rebar, provided certified material test reports (CMTRs). The values reported in the CMTRs are based on the results of a single tensile test. The CMTR value, while confirming the nominal material performance, is inadequate to determine "actual" material properties. The ASTM test standard recommends a minimum of three specimens be tested and the results averaged. Additional verification testing was performed as part of this test program to determine the "actual" or measured mechanical properties of the different heats of rebar employed in specimen assembly. Figures 1 and 2 show representative stress-strain curves for both heats of re-bar used in this test program.

3.1

1. 6 Re-Bar Material A common heat of rebar (CPS #589812899) was used in making up all #6-size coupler test assemblies.

Per ASME Section II, Division 2 requirements, the same 10 inch extensometer gage length, as would be used in the #6 coupler assembly tests, was used to measure strain in the tensile properties tests. Seven #6-size plain bar sections from this heat were tested to determine actual tensile-properties of this lot of material. Table I summarizes the test results. Material properties obtained from Consolidated Power Supply CMTR are provided for comparison.

It is apparent that the differences in yield strength as determined by three different definitions are minimal. For this type of steel, the yield point is the appropriate measurement and provides the most consistent value (smallest standard deviation). Where "measured" or "actual" yield strength is required in the analyses, 67.7 ksi is used for the #6L coupler tests. Where "measured" or "actual" ultimate tensile strength (UTS, or F) is required in the analyses, 107.5 ksi is used for the #6 tests.

Table 1. Mechanical Properties of Rebar Used in Test Specimens Yield Point 0.2%OS 0.5% EUL UTS (ksi)

Elongation E (Msi)

(ksi)

Yield (ksi)

Yield (ksi)

(%)

1. 6 Average 67.9 68.2 13.2 27.8

1. 6 StdDev 1.03 1.19 1.14 1.12 1.26 0.89

1. 6CMTR 67.6 107.4 15

1. 8 Average 72.4 72.5 11.5 29.2

1. 8 Std Dev 0.45 0.57 0.47 0.74 0.98 0.46

1. 8CMTR 73.1 112.0 14

1. 8 CMTR 69.0 112.8 16 (C-series only) 3.2

1. 8 Re-Bar Material A common heat of rebar (CPS 589813260) was used in making up all of the 8-size coupler test assemblies used in the tensile strength tests. Per ASIE requirements, the same 14.5 inch extensometer 2

gage length was used in the tensile properties test as would be used in the #8 coupler assembly tests.

Seven #8-size plain bar sections from this heat were tested to determine actual tensile properties of this lot of material. Table 1 summarizes the results of those tests. Material properties obtained from Consolidated Power Supply CMTR are also provided for comparison. Again, the yield point strength is selected for the material yield strength value. Where "measured" or "actual" yield strength is required in the analyses, 72.6 ksi is used for the #8 tests. Where "measured" or "actual" ultimate strength (UTS) is required in the analyses, 1 10.1 ksi is used for the #8 tests.

3.3 Material for #8 Coupler Size Cyclic Durability Tests A separate heat of rebar material (CPS # 123741) was used to fabricate the size #8 cyclic test coupler assemblies. There are no measured strength parameters (only specified minimums) associated with the cyclic test procedures, so no verification testing of this material was performed. The CMTR-reported values for this heat are provided at the bottom of Table 1 for reference.

4.

DESCRIPTION OF COUPLER TEST SPECIMENS The Bar-Lock couplers used are Bar-Lock's "L-Series" (coupler designations 6L and 8L), which are higher strength rebar couplers for use in tension/compression, seismic and other cyclic load conditions.

The specifications for these couplers are provided in Table 2.

Table 2. Bar-Lock L-Series Coupler Specifications (Sizes #6 and #8)

For Coupler Specifications Bolt Specifications Coupler Use Outside Length Nominal Quantity Size Nominal Designation Rebar Diarneter (inch)

Weight per Bar (inch)

Shear Size (inch)

(lbs.)

Torque (ft.-lb.)

6L

1. 6 1.9 8.0

.4.5 4

1/2 80 8L

1. 8 2.2 12.3 9.5 5

5/8 180 The component parts of each Bar-Lock coupler consist of a steel tube, "lock-shear" bolts, and serrated rails. Figure 3 shows a schematic diagram of the coupler design. The seamless, hot-rolled steel tube conforms to ASTM A-5 19, with a minimum tensile strength in excess of 100 ksi. The lockshear bolt material is AISI 41L40. The bolts are through-hardened over the entire bolt length and further induction-hardened at the conical bolt tip. The serrated rails are made of ASTM CDI 018. They are machined and then carburized to a depth of 0.032 in.

An equivalent testing program was performed for each of the two coupler/rebar sizes tested. For each size, forty test specimen assemblies were made up for tensile strength tests, and forty assemblies were made up for the cyclic durability tests. The test specimen assemblies were made up by steel construction workers using Bar-Lock's assembly instructions in a normal field environment. Assembly of the test specimens was monitored by Bechtel QC personnel.

f,--*

1.

5.

TEST RESULTS All of the 160 individual coupler specimens tested in this program, and all relevant specimen sample set averages and individual coupler strengths, exceeded the requirements set forth in the ASME Code, Section CC-4333.2.3(a).

Eighty tensile strength tests (forty of each size) were performed on coupler assembly specimens according to relevant sections of ASTM A 370 and E 8, and ASME CC-4333.2.3(a). A representative stress-strain curve for a coupler strength test is provided in Figure 4. No practical differences were observed in the general character of the stress-strain curve of any of the 80 specirens tested. All test data collected included stress, strain, crosshead displacement, applied force, and elapsed time. The actual individual test specimen results obtained through standard analysis methods provided in ASTM E 8 are tabulated in Tables 3 and 4. A representative stress-strain plot for a cyclic test is provided in Figure 5.

Table 3. Tensile Properties for #6 Rebar (Heat ID: 589812899)

Specimen HOF Yield UTS Ef E

ID (ksi)

(ksi)

(%)

(Msi)

U6-2 67.7 106.9 14.0 28.7 U6-5 66.8 106.6 13.5 27.4 U6-9 67.0 107.0 12.9 28.1 U6-11 67.6 107.8 14.2 28.6 U6-12 69.9 109.7 10.6 27.3 U6-14 67.9 107.9 12.9 28.3 U6-18 67.3 106.5 14.1 26.2 Averages 5

13.2 27.8 Table 4. Tensile Properties for #6 Rebar Heat ID: 5898I2899 Specimen HOF Yield UTS Ef E

ID (ksi)

(ksi)

(%)

(Msi)

U8-l1 72.5 110.3 12.9 30.1 U8-12 72.4 108.8 11.2 28.7 U8-13 71.7 109.5 12.2 29.3 U8-14 73.0 111.0 9.8 28.8 U8-16 72.8 110.2 11.0 29.1 U8-18 72,5 110.4 11.i 29.2 U8-20 73.0 110.6 11.5 29.1 Averages 2.e-6

¢ I 0.1 11.5 29.2 r

v. I A

In addition, several specimens of each size were randomly selected to receive an initial slip test prior to the normal strength test. A statistically-legitimate random selection process, using a random number generation algorithm on a computer, was applied to make the selections. Virgin test specimens were installed in the test machine, and instrumented as for a normal strength test. The applied stress was increased from 0, through 3 ksi, up to 30 ksi, and then reduced to 3 ksi. The change in displacement across the coupler between the two 3 ksi stress levels was measured with an extensometer. Figure 5 shows the traces of applied stress and resultant displacement for the six specimens. In all cases, no measurable slip was detected.' The observation of no bar slip within the coupler on initial loading means the coupler will develop full strength without excessive defornation upon initial loading.

5.1 Tensile Test Results The ASME Code, Section CC-4333.2.3, has several criteria with which coupler performance is compared.

The two pertinent criteria for the tensile strength test results are:

1. "...The average tensile strength of the splices shall not be less than 90% of the actual tensile strength of the reinforcing bar being tested, nor less than 100% of the specified minimum tensile strength."

2. "...The tensile strength of an individual splice system (test specimen)' shall not be less than 125% of the specified mininum yield strength of the spliced bar."

The coupler assembly performance for both sizes evaluated exceeded both of these criteria. Table 5 tabulates the results of the individual strength tests. Discussion of the comparisons of test results to ASME specified minimum values follow:

5.1.1 Minimum Average Tensile Strength Comparison For the lots of rebar tested, the "90% of the actual tensile strength" is the governing criteria.

For the size #6 group, the specified minimum average strength value is 96.8 ksi. For the size

1. 8 group, the specified minimum average strength value is 99.1 ksi.

5.1.1.1 Coupler/bar size #6 The sample set of strength data from the coupler/bar size #6 was evaluated for normal (Gaussian) probability distribution using the Wilk-Shapiro W-test and graphical analysis methods. The results show a near nornal distribution, i.e. only slight departure from normality. Where necessary in the assignment of confidence limits, the assumption of normality is justified.

The size #6 group (sample set, n = 40) average tensile strength is 106.2 ksi (98.8% of the average #6 bar actual tensile strength), with a standard deviation of only 1.87 ksi. The Code-the measured slip displacements, equivalent to less than 0.001 in. over the length of the coupler, were much less than observed hysteresis error in the extensometer.

2 This is a single average value, calculated from the entire group (sample set) of replicate test specimens, i.e. from one heat of material, in one size.

This is the strength value of each individual test specimen (coupler assembly) consisting of one coupler unit and two attached sections of rebar.

'3 ;, ^

required average strength value of 96.8 ksi (90% of actual tensile strength) is 5.0 standard deviations below the sample average. This corresponds to a probability of less than 3 in 10 million couplers would have strength less than the required 96.8 ksi minimum value. Further, a one-sided test for lower bound was also performed. This test provides a practical lower limit strength value for any #6L coupler assembly. Based upon this data set 99% of all couplers of this type will have a tensile strength greater than 100.13 ksi (with a 99%

confidence level). This is a very strong indication that the size #6 coupler design will achieve the required minimum strength. These results are confirmed in a letter report (see Appendix F) from INEEL statistician J.J. Einerson. Mr. Einerson reviewed the statistical analyses of the mechanical test data.

5.1.1.2 Coupler/bar size #8 The sample set of strength data from the coupler/bar size #8 was also evaluated for nornal (Gaussian) probability distribution using the W-test and graphical analysis methods. Again, results show only slight departure from normality.

The size #8 group (sample set, n = 40) average tensile strength is 109.0 ksi (99.0% of the average #8 bar actual tensile strength), with a standard deviation of only 2.78 ksi. The required average strength value of 99.1 ksi is 3.6 standard deviations below the sample average. This corresponds to a probability of less than 2 in 10,000 couplers would have a strength less than the required 99.1 ksi minimum value. Further, the one-sided test for lower bound (described above) based upon this data set indicates that, with 99% confidence, 99% of all couplers of this type will have a tensile strength greater than 99.94 ksi (see letter report included in the Appendix). This is a very strong indication that the size #8 coupler design will achieve the required minimum strength.

To assess the general capabilities of the overall coupler design, the results from both sizes tested can be normalized by their respective bar lot (mill heat) tensile strengths and combined into one sample set. In so doing, the conclusion is that the Bar-Lock coupler design produces a splice that will achieve an average strength that is 98.9% as strong as the rebar itself. It is obvious that this greatly exceeds the ASME Code-required 90% value. The cumulative standard deviation is 2.2% of the bar strength, making the required minimum strength 4.0 standard deviations below the sample average. The equivalent likelihood is that only 3 in 100,000 would fail to achieve a strength level equivalent to 90% of the bar ultimate strength.

5.1.2 Minimum Tensile Strength of Individual Specimens This requirement for each individual coupler tested provides additional assurance that the occasional sample tested that may have a relatively low strength value, as compared to the sample set average, at least has an absolute minimum necessary strength for structural considerations. For the Grade 60 rebar used in this study, this required value is 75.0 ksi, and is the same for all specimens tested. All specimens tested in this test program passed this test, and by a very large margin.

5.1.2.1 Binomial (Pass/Fall) Assessment In the simplest case, the pass/fail criteria can be applied directly. For the combined sample size of 80, with no observed failures (strength below 75.0 ksi), the statement can be made that with 90% confidence, no more than 2.8% of couplers would fail this test. By the nature of this tvpe of binomial probabilitv distribution (pass/fail), it is difficult to state reliabilities with v6v /v

a higher level of confidence without assessing many hundreds of samples. However, by normalizing the measured individual coupler strengths by the required value, an analysis of the amount of deviation on those values can provide a yet stronger comparison and corresponding statement of reliability.

5.1.2.2 Assessment Using Normalized Coupler Strength Distribution This distribution of normalized strengths shows that the average coupler strength is 144% of the minimum required level for individual couplers, with a standard deviation of less than 4%. So the required strength value is 11 standard deviations below the sample average. The probability tables do not show probabilities below 8 standard deviations from the mean, but at that value, the probability is less than 2xl 0-15 that the strength of an individual assembly would be lower than the requirement, i.e. practically impossible.

5.1.2.3 Assessment Using Alternative Strength Criterion A comment by the US Nuclear Regulatory Commission (USNRC), during a presentation on the Bar-Lock couplers on August 9, 2001, was that the minimum strength criterion for individual test specimens should be based upon the actual, measured yield strength of the bar material, rather than the specified minimum value (as done above, per the ASME qualification specification). This makes more sense from a practical view, and it removes one variable (the specified material yield strength) from the comparison. However, this approach does apply a more stringent test of the coupler capability, since the actual yield strength will always be higher than the minimum allowable. To apply this criterion, the size

1. 6 and size #8 specimens must be treated separately since the measured yield strength's of the two bar sizes are significantly different.

Size #6 Couplers Using the appropriately normalized test results from the #6 test specimens, the same analysis described above was carried out. The size #6 coupler specimen tensile strengths averaged 106.2 ksi, 25.4% above the USNRC-proposed strength level of 84.6 ksi (125%

• 67.7 ksi) with a standard deviation of 1.86 ksi. The proposed minimum strength here is still more than 11 standard deviations above the proposed minimum level, with the probability being essentially zero that any coupler would fail to achieve this strength level.

Size #8 Couplers Analyzing the normalized test results from the #8 test specimens show their tensile strengtis averaged 109.0, 20.1% above the USNRC-proposed strength level of 90.8 ksi (125%

• 72.6 ksi) with a standard deviation of 2.81 ksi. The proposed minimum strength here is still 6.5 standard deviations above the proposed minimum level. The resultant failure probability is still less than xlO-10.

5.1.3 Tensile Strength Performance Exceeds Requirements The overall strength performance of the Bar-Lock coupler design can be summarized as excellent, based on this comprehensive test program of different size couplers. There were no failures to meet any of the specified or proposed strength criteria in any case. As the various failure probability values indicate, the likelihood of any individual Type 6L or 8L coupler assembly failing to achieve the ASNE required strengtl levels is very low.

i2 i/'

Table 5. Re-Bar Splice Assemblies Strength Test Results Lilure Final ype4 Strain (%)

NA5 O

3.8 P

15.2 p

14.4 p

15.2 O

4.9 O

4.1 O

4.2 p

13.1 T

2.7 O

4.6 p

13.0 O

4.4 T

2.7 P

10.8 p

12.3 O

3.8 P

9.8 P

11.5 p

19.1 p

15.4 p

11.0 p

11.6 T

2.7 O

4.1 UTS (ksi) 107.9 108.0 98.9 106.4 107.3 107.8 107.6 106.9 103.2 107.6 107.3 105.6 103.4 105.8 104.0 108.0 103.7 106.3 106.1 107.6 106.0 105.0 103.1 107.8 Specimen ID (#8)

Average S8-01 S8-02 S8-03 S8-04 S8-05 S8-06 S8-07 S8-08 S8-09 S8-10 S8-11 S8-12 S8-13 S8-14 S8-15 S8-16 S8-17 S8-18 S8-19 S8-20 S8-21 S8-22 S8-23 S8-24 IF iilure Final

.ype Strain (%)

NAb O

3.7 T

1.4 O

4.9 O

3.7 p

10.4 T

4.9 T

4.4 T

3.6 O

3.6 T

1.8 T

2.1 3.8 O

3.4 T

3.2 3.7 T

4.0 T

2.1 T

4.5 T

4.0 O

4.6 T

3.5 T

4.3 T

3.8 T

3.3 IUTS (ki) 109.6 96.8 109.8 110.1 108.4 109.7 110.4 109.4 110.5 102.1 106.0 108.0 110.5 110.1 106.7 111.0 104.5 109.3 109.4 110.1 109.7 109.4 109.8 108.5 B = bar break outside coupler but within extensometer gage length, 0 = bar break outside coupler and outside extensometer gage length, T = bar break at tip of first lock bolt, P = bar pulled out of coupler without breaking, = bar break in interior of coupler 5 The fmal strain is dependent on several factors, including mode of failure. An average value for all tests has no significance.

For example, in a pull-out failure the final strain is determined by the length of time the operator chooses to continue the test once pull-out is observed.

2 4.

Fa T

Specimen

]D (#6)

Average S6-01 S6-02 S6-03 S6-04 S6-05 S6-06 S6-07 S6-08 S6-09 S6-10 S6-11 S6-12 S6-13 S6-14 S6-15 S6-16 S6-17 S6-18 S6-19 S6-20 S6-21 S6-22 S6-23 S6-24

Specimen Failure Final UTS Specimen Failure Final UTS ID (#6)

Type4 Strain (%)

(ksi)

ID (#8)

Type Strain (%)

(ksi)

Average NA)

Average NAb S6-25 P

11.5 105.1 S8-25 P

10.4 110.0 S6-26 P

11.3 107.9 S8-26 T

4.2 109.9 S6-27 P

12.2 106.4 S8-27

• P 7.0 109.7 S6-28 0

3.9 107.8 S8-28 T

4.1 109.0 S6-29 B

4.8 107.0 S8-29 0

3.8 109.7 S6-30 0

4.3 107.6 S8-30 0

3.5 110.3 S6-31 0

4.4 107.4 S8-31 T

3.9 110.5 S6-32 T

3.8 107.2 S8-32 T

2.5 109.0 S6-33 T

2.9 105.7 S8-33 0

4.4 110.3 S6-34 P

12.6 105.7 S8-34 T

3.5 109.7 S6-35 T

4.4 107.2 S8-35 T

2.5 105.4 S6-36 T

2.8 104.2 S8-36 T

4.1 110.5 S6-37 0

3.8 107.2 S8-37 5.0 110.2 S6-38 P

11.5 107.4 S8-38 P

10.3 109.9 S6-39 P

12.9 107.0 S8-39 T

3.9 111.2 S6-40 P.

11.3 106.3 S8-40 P

10.2 113.6 5.2 Cyclic Test Results Coupler assemblies were cyclically tested according to the requirements of ASME CC-4333.2.3(b). Forty specimens of each of the two types (6L and 8L) received 100 load cycles between 5 and 90% of specified minimum bar yield strength (60 ksi). None of the specimens failed in any manner, e.g. bar break, or bar slip within the coupler.

Applied stress and specimen extension data were digitized during the cyclic tests to provided additional insight into the coupler performance under cyclic load conditions. Figure 6 shows a repre;sentative plot of stress versus displacement. For clarity, only every tenth cycle is presented. It shows the accumulated slip over 100 cycles to be less than 0.00 15 in. This is less than 10% of the elastic deformation that occurs during a single load cycle. The same behavior was observed in all of the tests of both coupler sizes. The couplers showed no significant deterioration (visible, or evidenced by deviation is test data) during the tests.

Based on the binomial probability function (pass/fail testing), and no observed failures in 80 tests, it can be stated with 90% confidence that less than 2.8% of all couplers would fail prior to the completion of 100 loading cycles.

5.2.1 Higher Count Cyclic Tests In an effort to improve the cyclic durability performance assessment, several of the specimens in each size were selected at random to receive additional cyclic loading. Each selected specimen was subjected to an additional 1000 cycles. None of the specimens failed, and none of them showed signs of deterioration through excessive strain accumulation or physical deformation. While this does not provide a verifiable improvement in the statistical probability of failure (the confidence level is too low to be useful), it does provide an engineering indication that the cyclic durability of the couplers will far exceed 100 cycles.

5.2.2 Residual Strength Tests Another test was also performed on randomly selected couplers to provide additional information regarding cyclic durability and residual strength. The selected couplers, all having been subjected to 100 loading cycles, were subsequeritly loaded to failure monotonically. This is the standard "tensile strength test" described in the previous section. The concept here is to determine if the prescribed cyclic loading substantially damages the integrity of the splice assembly. The eight specimens tested all achieved the same nominal strength as the corresponding specimens receiving no cyclic loading. Table 6 summarizes these test results. These observations suggest that cyclic loading in the stress range from 3 to 54 ksi does very little, if anything, to reduce the strength capacity of a spliced joint made using the Bar-Lock L-series coupler.

Table 6. Results of Residual Strength Tests on Load-Cycled Specimen Assemblies Specimen Failure Final UTS Specimen Failure Final UTS ID (6)

Type Strain (%)

(ksi)

ID (#8)

Type Strain (%)

(ksi)

Average NA 104.9 Average NA 106.7 C6-2 P

3.8 104.3 C8-15 106.6 C6-3 P

3.7 106.3 C8-21 106.0 C6-7 P

5.0 106.2 C8-27 107.6 C6-14 p

7.0 103.3 C6-15 P

3.7 104.5

6.

COUPLER TEST PROGRAM CONCLUSIONS The Bar-Lock coupler qualification testing progran was carried out on two representative sizes - #6 and

1. 8 - of their L-Series couplers. One hundred-sixty (160) coupler assemblies were tested. Fourteen (14) pieces of plain rebar were tested to determine the actual, or measured, mechanical properties of the two heats of bar material used in the test specimens.

6.1 Tensile Strength The tensile strength tests on 80 samples from each of the two sizes all exceeded the two ASIE requirements by a large margin. Statistical analyses of the test results determined several important performance indicators. all of which suggested that anv given coupler assembly would far exceed the In

ASME-specified strength requirements. The overallprobability of any coupler assembly (in size #6 or

1. 8) failing to meet the minimum qualification strength criterion is less than 3 in 100,000.

There was some variation in strength between the two heats of rebar used in the strength tests.

Comparing and correlating these results show that Bar-Lock L-Series coupler splices can be expected to achieve a tensile strength greater than 96% of the actual strength of the bar material that is connected using the coupler device. While there are not enough different combinations of bar material and coupler size data to make this statement with high probabilistic certainty, the combined test results from this program appear similar when nornalized by the actual bar strength. Therefore, it is likely these test results are representative of the performance of other sizes of Bar-Lock L-Series couplers. In other words, the mechanical design of the Bar-Lock L-Series coupler is such that spliced joints can be expected to develop over 96% of the actual bar strength.

6.2 Mechanical Slippage in the Couplers Slip tests performed on selected specimens of both sizes showed a solid mechanical connection between the coupler and the rebar. There was no tendency for the rebar to move within the coupler prior to developing full splice strength. This was expected since the conical-tipped lock bolts physically embed into the bar material providing a physical shear force transfer from bar to coupler.

6.3 Cyclic Loading Durability All 80 splice specimens that underwent the cyclic loading durability test passed the 100-cycle test, with no obvious physical degradation of the spliced joint. To provide an additional degree of assurance of adequate cyclic durability, selected specimens received 1000 cycles of loading, again with no noticeable physical degradation. Some of the specimens that passed the 100 cycle test were subsequently tested by monotonic loading to failure. The resultant measured strengths were essentially the same as the virgin strength test specimens (no cyclic loading applied). These results suggest that the design of the Bar-Lock coupler is essentially insensitive to cyclic loading to levels below 90% of the minimum bar yield strength.

6.4 Overall Coupler Performance All of these test results, compared to the ASME splice system qualification requirements, indicate that the Bar-Lock coupler design for rebar splicing is entirely adequate from a strength point of view for use in nuclear safety-related construction. The large quantity of couplers tested provides higher confidence that the couplers do meet, and indeed far exceed, those ASME-specified requirement.

L -.

120 100

/

B~~U6-18

/

~~Size

1. 6 Rebarl 80 Heat X589812899

,u 60 20 o

0 4

8 12 16 Engineering Strain (%)

Figure 1. Representative Stress-Strain Curve from #6 Rebar Material

~~~~~~~~~~~~~~~

1-,

120 100 80 f=

no1 60 40 20 _

O 1

I I

I I,,,

1, 0

4 8

Engineering Strain (*)

Figure 2. Representative Stress-Strain Curve from #8 Rebar Material 12 16 A

A - Coupler Barrel B - Lockshear Bolts C - Serrated Rails.

D - Center Pin Figure 3. Bar-Lock Coupler Cutaway View Showing Internal Details

..1'

Crosshead Displacement (in.)

0 0.5 1

1.5 2

120 I

I I

100 Extensometer removed 80 at 2% strain level 2

/

I~~~

60 I

~~~~~~~S6-29 l /

l 10" G.L. Strain 40 Il Crosshead Position 0

I I

I

,fI 0

1 2

3 4

Strain (%)

Figure 4. Representative Test Data from a Coupler Assembly Strength Test Cs Z 0

14

40 30 s3

~20 Found knife edges on extensometer to be loose following the test 0.000 0.002 0.004 0.006 0.008 0.010 0.012 Displacement across Coupler (in.)

Figure 5. Data Curves Showing Load-Unload Cycle to Assess Bar Slip in Couplers f~~~~~~

60

-S en Specimen #C8-21 20 10 Only ~~~~~~~1, and every' 1 Qth cycle shown for clarity I

I 0.000 0.005 0.010 0.015

. 0.020 0.025 Displacement across Coupler (in.)

Figure 6. Cyclic Stress-Displacement History for a Typical Test t

ATrACHMENT 2 Valley Machining (Typical Inspection and Testing Record Sheets)

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Valley Machining Co 1250 22nd Avenue PO Box 155 Rock Valley, IA 51247

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3-V2 BoR Lot #

L17R2 Lot Qty Ship Qty Ship Date:

.est wt uty Qty Parameter Specification Pass Fail Pass Fail Major Diameter

.618 68 (maxlmin)

.628 Pitch 2.00 68 Fit 6g 68 Lengthi "E" 0.9a.4 68 (dim. +I-.010) 0.984_68 180 Shear (ft-Lbs) 68 Torque 205 In-process Test Results High Low Accept Reject Ind-Hard __

54/64 64 62

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161 2

• 182 3

183 7

184 3

185 6

186 3

187 17 188 1

- 189 3

190

. 9 191 5

192 6

193 1

194 1

195 196 197 198 199 200 7

201 202 203 204 LOT ACCEPTED VMC REVIEW V

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ph.: 1712-476 --

prepared by: Will Schader ph.: 1.712476-25 4,474 Bolt Size:

Date of Te sample s Nuclea NOTES:

NOTES:

HISTOGRAM

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~~~~~~~~~~~~~..................................................

Bolt Size:

M12-N Date of Test:

5/24/01 Revision:

3 Bolt Lot#:

L1 9R2 Lot Qty:

4,843 Ship Qty:

Ship Date:

. Isamplesize

.68 l

Nuclear App. Bolt i est

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.ty ty Parameter Specification Pass Fail Pass Fail Major.

Diameter

.461 68 (max/min)

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Shear (ft-Lbs) 80 8068 Torque 88 In-process Test Results High Low Accept Reject nd-Hard 54/64 63 T

61 NOTES:

NOTES:

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oh.: 1-712 476-2828 1

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Form POP-053 10,10':00 Shear Torque HISTOGRAM Data Quantity 80 1Is 81 9

82 10 83 33 84 7

85 8

86 87 88 1

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