ML20080A614
| ML20080A614 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/30/1984 |
| From: | Mary Walsh Citizens Association for Sound Energy |
| To: | |
| Shared Package | |
| ML20080A604 | List: |
| References | |
| NUDOCS 8402060161 | |
| Download: ML20080A614 (21) | |
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UNITED STATES OF AMERICA -
NUCLEAR REGULATORY COMMISSION, BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of I
APPLICATION OF TEXAS UTILITIES Docket Nos. 50-445 GENERAi1NG COMPANY, ET AL. FOR and 50-446 AN OPERATING LICENSE FOR COMANCHE PEAK STEAM ELECTRIC I STATION UNITS #1 AND #2 I (CPSES) l AFFIDAVIT OF MARK A. WALSH 1 Q: Mr. Walsh, do you have any coments in regards to the Applicants' 2 quality assurance program as discussed in the Applicants' Motion for Reconsidera-3 tion of Memorandum and Order (Quality Assurance for Design)?
4 A: Yes, I do.
5 The first item .I would like to address is Applicants' Attachment A, 6 " Summary of' Quality Assurance Program for Design of Pipe Supports for Comanche 7 Peak Steam Electric Station."
8 As I will discuss later, the program they have cited is only on 9 paper. The procedures indicated in their Summary may be implemented at other 10 sites, but not at Comanche Peak (at least while I was there). What is most 11 important is the- testimony provided by the Applicants' witnesses. in regards 12 to the Walsh/Doyle allegations, as summarized in CASE's 8/22/83 Proposed 13 Findings of Fact and Conclusions of Law (Walsh/Doyle Allegations) and in the 14 Board's 12/28/83 Memorandum and Order (Quality Assurance for Design), along 15 with other information already in the record.
16 To me, the reality of Applicants ' attitude toward 10 CFR, ANSI, 8402060161 840201 PDR ADOCK 05000445 G PDR
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s 1 and ASME is denonstrated through NCR M-1802 and its Revision 1 (accepted into 2 the record as CASE Exhibits 498 and 497, respectively), dated 11/5/79 and 3 ' reported by J. Patton. As shown in block (3) of the original NCR, the 4 " Document Violated" was 10CFR50 App. B Pt. V & VIII." On the revision, 5 block (3) indicates the " Document Violated" was "ASME Section III." There are several other changes which were made in the original and Revision 1 6
/ of this NCR (for example, block (9), Review / Approval, was signed by two 8 different individuals on two different dates, as indicated in block (10)).
9 Of particular concern to me and CASE is the Summary (on the second 10 page of .the document). The Summary Mr. Patton wrote on the original NCR 11 is as follows:
12 " Exhibits I & II attach'ed show loss of control and failure to conform to sections V and VIII of 10CFR50, Appendix B by both craft and Engi-13 neering personnel. The drawing control and design change controls as specified in site Procedures has been neglected such that both these 14 documentation packages cannot support these applicable regulatory requirements. " (Emphasis added.)
15 16 Referring to Revision 1 of the NCR, one will notice that there is no 17 Summary.
18 This is important because the 12/28/83 Board Order cited the same 19 general issue, Applicants' noncompliance with 10 CFR Part 50, Appendix B, 20 as was cited in the original NCR's Summary. The Applicants have, by their 21 convenient handling of this NCR, dismissed the 10 CFR Part 50 violation, by 22 revising it as shown in Revision 1 of the NCR. The reason for the revision 23 is not given. Rather than adding to the original NCR, the original informa-24 tion was changed. The original NCR was not dispositioned, but the Summary 25 was deleted and the document violated as well as item II.B. was changed (again
1 without explanation). This technique of modifying NCR's will not aid the 2 NRC or the Board in regards to the trending of deficient items or of violations 3 of 10 CFR. Even if the Applicants were now able to explain the reason for a 4 revision to the initial NCR, the explanation from the treading standpoint 5 would be meaningless.
6 A confusing point shown in these two NCR's is item II.B. In the 7 original NCR, it states " Hole spacing has been changed on the ABRF" (emphasis.
8 added); on the revised NCR, item II.B. states "Hilti bolt size has been changed 9 on the ABRF" (emphasis added). No reason is given for this change.
10 The Disposition of NCR M-1802 R1 (pages 3 and 4 of 28) reveals
.11 more information in regards to the procedures utilized by the Applicants regard-12 ing nonconforming conditions. Item ID. reveals the problems of who is respon-13 sible, for what, and when. On page 15 of 28, the title block of the drawing 14 states "ITT Grinnell, Pipe Hanger Division" (emphasis added). Disposition 15 of item ID. states ". . . welds No. 3 thru 9 are vendor shop welds." (Emphasis 16 added.) On sheet 11 of 28, a request for change is by NPSI fabricator. On 17 page 12 of 28, the reason for change is "can not be fabricated as detailed."
18 The request came from Hal Goodson of the Hangers Department. On page 13 of 19 28, the CMC is requested by Hal Goodson of the Hanger Eng. Dept. It is my 20 understanding that Hal Goodson was not an engineer and that he das at that 21 time superintendent of the steel fabrication and hanger department. In addi-22 tion, the disposition of this NCR was accepted by Gibbs & Hill, Inc. to "use 23 as is" as shown on page 5 of 28; this appears to be Gibbs & Hill approval 24 of the method of design and fabrication by ITT Grinnell, NPSI, and/or Brown 25 & Root.
l It is a standard industry practice for field engineers to make
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1 2 minor changes to construction documents, and later (less than 90 days) to have 3 those changes approved or disapproved by their home office and if acceptable, 4 those changes are then incorporated on the original drawing. - Also, it is 5 an industry practice for field engineers to request changes, and resident 6 engineers (engineers from the home office who have access to the original 7 calculations) to approve changes or disapprove changes and incorporate changes 8 into original calculations prior to construction of the field change. It 9 is not industry practice for construction to request a change in a design 10 document, and have a field engineer, who has no access to the original cal-11 culations, approve such a change, as is the case at Comanche Peak.
12 The abuse of CMC's has the consequence of avoiding the proper 13 trending and prompt correction of deficiencies, as is further shown when one 14 observes CMC 17671, page 18 of 28 of NCR M-1802 Rl. This CMC was gene ~ rated 15 by the Hanger Dept. The reason for the change is "misfabrication by NPS."
16 (Emphasis added.)
17 The abuse of CMC's is compounded when one looks at the approval box.
18 On page 11 of 28, for example, the approval came from G. M. Chamberlain.
19 It is ray understanding that Mr. Chamberlain had no previous engineering ex-20 perience prior to Comanche Peak or the proper qualifications for an engineer.
21 It is not apparent from the information contained in the NCR who 22 or what organization provided the material and who welded :the material to-23 .gether, since the initial drawing was an ITT Grinnell drawing, a CMC claimed 24 that NPSI had misfabricated it, yet a Brown & Root superintendent of the 25 fab shop initiated another CMC -- all against the same support.
l, .
1 It appears .that the original NCR was correct that the Applicants 12 were in violation of.10 CFR Part 50, Appendix B.
3 4- It also appears that the NRC Senior Resident Inspector at Comanche 5 Peak, NRC Staff witness Robert Taylor, was aware of the construct / design 6 . philosophy at Comanche Peak and was concerned about it, & indicated in his 7 1979 Trend Analysis for Comanche Peak (NRC Staff Exhibits 192-195) and in his
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8 supplemental testimony for the June 1982 hearings (NRC Staff Exhibit 180, 9 Supplemental Testimony of William A. Crossman, Robert C. Stewart and Robert 10 G. Taylor Regarding Annual Assessments of- Applicants' Performance (Contention 11' 5)). On page 16 of his Testimony, Mr. Taylor stated, in part:
12 "What I.had begun to see, but had difficulty proving, was that the.
Brown & Root construction philosophy was to build something any way 13 they wanted to and then leave it up to the engineer to document and approve the as-built condition. If the engineer refused, he was blamed 14 for being too conservative and not responsive to the client's needs."
15 And on page 17, he stated, in part:
16 "In a couple of cases, I had been able to show them that their people were essentially incompetent even though they had been through the site 17 training and h'ad been certified as competent. I saw a desire on the part of the licensee to turn this situation around in the important 18 areas of electrical and piping installation. However, too often an installation was clearly constructed other than as originally designed 19 and had been approved by the licensee's on-site engineering arm as fulfilling requirements. In effect, the engineer had approved a 20 ~
nonconforming installation in advance of QC being called. QC was then signing for the as-built condition and the underlying problem was not 21 addressed." (Emphases added.)
22 It is evident from the preceding that Mr. Taylor was aware that this 23 had been, and probably still was, the practice at Comanche Peak as far back
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24 as 1979; however, this is contrary to the impression he gave during the
-25 May 1983 hearings.
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6-1 The preceding is important also in that it clearly indicates that 2 this had been the practice at Comanche Peak not just regarding pipe supports, 3 'but "in the important areas of electrical and piping installation" (emphasis
'4 added) as well. Jack Doyle and I have not addressed these areas, but there 5 is every reason to believe that problems of the same magnitude exist in those 6 areas as exist regarding pipe. supports.
7 It should also be noted that the Applicants' FSAR Section 17, 8 at page 17.1-39, at the time of the Walsh/Doyle allegations, stated:
9 "A nonconformance report is utilized for the identification, documenta-tion, dispositioning, and verification of deficiencies in characteris-10 tics, documentation, or procedures which render the quality of an item unacceptable or indeterminate."
11 12 And on the same page, it will be noted, it states that:
13' " Procedures require ' trending' of nonconformance and deficiency reports to identify trends adverse to quality."
14 (See FSAR page 17.1-39, May 31, 1979, attached to CASE's Motion to 15 Supplement the Record (In Regard to Walsh/Doyle Allegations).)
16 It does not state that trending is done on CMC's.
17 On July 11, 1983, Applicants changed their FSAR to document in 18 writing that NCR's no longer have to be used for all nonconfonning conditions.
19 FSAR page 17.1-39, Amendment 41, July 11,1983 (attached to CASE's Motion to 20 Supplement the Record (In Regard to Walsh/Doyle Allegations) states:
-21 " Procedures require ' trending' of deficiencies identified on nonconformance reports, deficiency reports, and inspection reports to identify trends 22 adverse to quality."
23 It does not state that trending is done on CMC's.
24 25
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1 .Q: On page 26 of their pleading, Applicants address the role that you 2 and Mr. Doyle fulfilled at Comanche Peak. Do you have any comments regarding
-3 'this?
4' A: Yes. . I believe the perception provided by the Applicants, while 5 partially correct, is deceiving. While Jack Doyle and I may have analyzed 6 1084 individual supports, it appears that Applicants are trying to show 7 that we only identified "a few design deficiencies in supports" (page 26, 8 second full paragraph). Although this may be the Applicants ' perception, 9 it.is far from the truth. When I testified back in July of 1982, I had only 10 one day of preparation, and I did not recall .all the problems at Comanche 11 Peak. Since then I have recalled other deficiencies, which have not been 12 addressed before.
13 The first such item is the reduction in sectional properties in 14 a tube steel member at a Richmond insert. To anchor the tube steel with a 15 threaded rod to the Richmond insert, a hole is drilled through the tube 16 . steel. This hole has decreased the section properties of the tube steel 17 section at .the connection. I informed NPSI of this condition while I was 18 at Comanche Peak, but to the best of my knowledge and belief, the -eduction 19 of ttbe steel properties was not considered in the design process.
20 To illustrate, referring to Attachment A to my affidavit, which 21 I have prepared, Figure 1 is the cross-section of a tube steel section with-22 out the hole drilled in it. Its properties for a TS 4x4xl/2 are: Area =
23 6.14 in.2; moment of inertia = 11.4 in.4; and section modulus of 5.7 in.3 24 (using 7th Edition steel properties).
25 In Figure 2 of the Attachment is the same tube steel shape, but
1, at the Richmond insert where a 1-5/8" diameter hole has been drilled to 2 accommodate the threaded rod, its properties are as follows: Area = 6.14 3
-(2)(1/2)(1-5/8) = 4.52 in.2; moment of inertia ~ 11.4-(2)(1/2)(1.625)(1.75)2 4 = 6.423 in.4; and the section modulus is 6.423/2 = 3.211 in.3 .
5 It is apparent that there is a reduction in properties-at the connection 6 of a Richmond insert. The most significant reduction is that of the section 7 modulus. To-illustrate this problem, see Figure 3 of Attachment A. This 8 is a 2 span continuous beam with two concentrated loads with dimensions 9
as shown. The moment in the beam at support point B is (3/16)(10)(5) =
10 9.375 kip-ft. The bending stress, using a full tube steel section modulus 11 is (9.375)(12)/5.7 = 19.7 ksi at support point B.
12 The bending stress in the tube steel using the actual section modulus 13 at support point B is (9.375)(12)/3.211 = 35 ksi. The allowable bending 14 stress for A500 Grade B tube steel. is.(.67)(36) = 24 ksi. Therefore, this 15 member would be highly overstressed.
16 17 Another item I have not previously mentioned is overstressed liner 18 plate attachments. NPSI has attached to the liner plate with an assembly 19 similar to what is shown in Figure 4. Plate A is the member that is being 20 overstress ed. I became aware of this problem about Decmeber 1981 or January 21 1982. I infonned the NPSI group that plate A had a bending stress of 60 ksi 22 when analyzed with normc.) ;Mrating loads, and returned the support package 23 back to them.
24 One month later, the same support package came to the STRUDL group 25 to be reanalyzed. I once again informed NPSI of the overstressed plate.
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1 This time I was instructed not to model' in the plate. I was told that the
.2 plate was not NPSI's but Gibbs & Hill's responsibility, and that Gibbs &
3 ' Hill had accepted it although NPSI knew it was overstressed.
4 Other problems that I remember, which I saw while on my trips 5 through the plant were:
6 (1) A cantilever with only two anchor bolts loaded about its weakest 7 di rection. (Cygna also saw this condition on a cable tray support.)
8 (2) On an axi'l restraint, I had analyzed for ITT Grinnell, using their 9 procedures, the lug showing the greatest amount of load had a distance between 10 the lug welded to the pipe and.the supporting member of approximately 1/16 11 in, gap.
12 (3) The dry wall in the control room is hung with wire and I do r.ot 13 consider this to be seismically qualified. .
14 (4) An HVAC duct within tne Containment Building rises a considerable 15 length without any axial restraint. I question the capacity of the sheet 16 metal to resist buckling in the event of a seismic motion.
17 Another point not previously discussed is the number of supports 18 evaluated by myself and Jack Doyle. While I do not know the exact acount,
-19 I do know that it was more than the Applicants have stated. This could be 20 verified by using the log book I used to maintain as the group leader, and 21 I believe was maintained when I decided not to keep that position wit ~ out 22 proper compensation.
23 If one were to audit the log book, one would see that Jack Doyle and 24 I did the majority of the problems (there were five of us, not including 25 Gary Krishnan, the supervisor.) If one looked at the production before I
l1 ' ' became group leader and compared it to 'the production after~ I became group l2 leader and before Jack Doyle became a member of the group, the average for 3 the group went from about five problems a week _ to about eleven problems 4 a week which we handled. The five.a week was based.on counting each support 5 which had two-way restraints as being two supports; the eleven ~a week counted 6- each support with two-way restraints as aasingle support.
-7 In addition, Jack Doyle preferred to do the more difficult problems; 8'
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for example, Gary Brown's Space Frame that was discussed during the LOCA
'9 issue, or taking difficult problems from the only TUSI employee so that she
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10 could do the easier ones.(which also made her average 'look better).
11 I mention this primarily to point out that one doesn't have to sacrifice L 12 quality to increase production. Even though Jack Doyle and I were concerned
- 13 .about quality, we were able to do our work'and still take a few plant tours
.14 and identify some specific problems.
15 ,
16 Q: Do you have any comment regarding Applicants' proposal that addi-tional hearings be held-on the closed Walsh/Doyle items?
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- 18. A: Yes. The Applicants should have been serious when they had the L
19' opportunity to present infonnation to this Licensing Board in regards to 20 the Walsh/Doyle allegations and should have gotten all their infonnation l
21 in to show their position and not stuck with generalities. If this is the 22 attitude they have_ for these hearings, the Applicants will most likely main-L l- l23 tain that attitude when they get an operating license, if they get one.
24 If they were .not serious about these hearings, they likely will not be serious
- i. 25 about operating the nuclear power plant.
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1 I was serious when I made my allegations and'I assumed the Appli-2 cants were equally serious since they hired Mr. Reedy and others to be their 3 expert witnesses to address our allegations. I also spent a considerable 4 amount of time preparing for the hearings, helping write the Proposed Findings 5 of Fact, and participating in the hearings. I am not being paid as a consultant 6 for doing this, and I do not want to have to go through this another time.
7 8 Q: Is there anything further you would like to discuss?
9 A: Yes, in regards to AWS (pages 33-37 of Applicants' pleading).
10 The Applicants continue to state that they are not required to meet the re-11 quirements of AWS. But the Applicants are required to provide a safe plant, 12 no matter what Code is used. In regards to the recapping of the 382 deficient 13 fillet welds on NPSI supports, Mr. Doyle is correct in his assessment of 14 the shrinkage problem with minimum fillet weld size. The AWS welding code 15 at Section 2.7.1 (see Attachment B to this Affidavit) requires the minimum 16 fillet weld to be placed in a single pass, and this is based only on thickness 17 of base metal. The Commentary to the Code, at Section 2.7.1, provides the 18 reasoning for the minimum size fillet weld, and this reasoning compliments 19 the statements made by Mr. Doyle. It should also be noted, all additional 20 passes must be the same minimum size.
21 This minimum fillet weld size for the first pass, and all additional 22 passes, is a major problem because of cracking of the weld or base metal.
-23 To the best of my knowledge, the Brown & Root welding procedures will not 24 accomodate this minimum size, particularly the 1/4" fillet weld in a single 25 pass.
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ATTACHMENT B ANSI /AWS D1.1-82 O
. ANSI /AWS D1.1-82 An American National Standard Approved by American National Standards Institute January 25,1982 Structural Welding Code-Steel Sixth Edition Superseding AWS DI.I.81 Prepared by AWS Structural Welding Committee
, Under the Direc' ion of AWS Technical Activities Committee Approved by AWS Board of Directors Effective January 1.1982
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ATTACHMENT B Details of SYeldedJointsI$
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Table 2.3.1.4 2 _, j i d__lg d b Effective throats of flare groove welds l Flare-bevel- Flare-V- h h groove welds groove welds ,
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9 j j U All diam bars , \ ransverse T
welds may 1/2 R* )-, L 5/I6 R .
T ,i l , be used along
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Note: R = radius of bar. Ef fective- +- , ,
- Except 3;8 R for GMAW texcept short circuiting transfer) size prow; with bar sizes I in. t 25.4 mm) diam and over.
~ *- Actual size Note: The effactrve area of weld 2 shall equal that of weld 1 but its size shall be its of fective size plus the thickness of the filler T.
Fig. 2.4.2-Fillers less than 1/4 in. thick p
Details ofWeldedJoints 2
2.6 Joint Qualification "eQ f '-- -"
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2.6.1 Joints meeting the following requirements are des- b %
ignated as prequalified: ,
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, (1) Conformance with the details specified in 2.7 k [= j I ;- Mx 4 through 2.10 and 10.13. / J Transverse (2) Use of one of the following welding processes in "dd' **Y N
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' 2 1 accordance with the requirements of Sections 3,4. and 8. {"
9, or 10 as applicable: shielded metal arc, submerged arc, [,"ngn,,, L, , ,i gas metal arc (except short circuiting transfer), or flux enes 4 _ _ _ >/
cored arc welding. >
2.6.1.1 Joints meeting these requirements may be used '
without performing the joint welding procedure qualifi-I cation tests prescribed in 5.2.
Notes:
I 2.6.1.2 The joint welding procedure for all joints
- 1. The etfective area of weid 2 shall equal that of weld 1. The welded by short circuitine transfer gas metal are welding length t weld 2 sha'i be suf ficient to avoid overstressing the (see Appendix D) shall be qualified by tests prescribed in fdler in shear along planes x-x.
$ "," 2. The etfective area of weld 3 shall at least equal that of weld 1
' and there she'l be no overstress of the ends of weld 3 resulting 2.6.2 Joint details may depart from :he details prescribed fr m the eccentricity of the forces ac*ing on the filler.
in 2.9 and 2.10 and in 10.13 only if the cuatractor submits to the Engineer his proposed joints and joint welding Fig. 2.4.3-Fillers 1/4 in. or thicker j procedures and at his own expense demonstrates their adequacy in accordance with the requirements of 5.2 of this Code and their conformance with applicable provi-2.7.1.1 The minimum fillet weld size, except for fillet sions of Sectio w 3 and 4. ,
welds used to remforce groove welds, shall be as shown in Table 2.7.
2.7.1.2 The maximum fillet weld size permitted along l
2.7 Details of Fillet Welds edges of material shall be (1) the thickness of the base metal, for metal less than 2.7.1 The details of fillet welds made by shielded metal 1/4 in. (6.4 mm) thick (see Fig. 2.7.I, detail A).
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arc. submerged arc, gas metal arc (except short circuiting transfer), or flux' cored are welding to be used without joint welding procedure qualifications are listed in 2.7.1.1 (2) 1/16 in. t 1.6 mm) less than the inickness of base metal. for metal 1/4 in. (6.4 mm) or more in thickness (see Fig. 2.7.1, detail B), unless the wc!d is designated on through 2.7.1.5 and detailed in Figs. 2.71 and 10.13.5. the drawing to be built out to obtain full throat thickness.
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ATTACHMENT B Details of weldedlointsl7
,7 O transfer), or flux cored are welding processes are listed in thickness of the part containing it, except those ends 2.8.2 through 2.8.8 and 3.3.1 and may be ased without which extend to the edge of the part.
performing the joint welding procedure qualification pre.
scribed in 5.2, provided the technique provisions of 4.21 2.8.7 The minimum spacing of lines of slot welds in a or 4.22 as applicable, are complied with. di m ia e m e kl @ M I k M n W width of the slot. The minimum center-to-center spacing 2.8.2 The minimum diameter of the hole for a plug weld in a longitudinal direction on any line shall be two times shall be no less than the thickness of the part containing it the length of the slot.
plus 5/16 in. (8.0 mm), preferably rounded to the next greater odd I/16 in. (1.6 mm). The maximum diameter of 2.8.8 The depth of filling of plug or slot welds in metal the hole for a plug weld shall not be greater than 2-1/4 5/8 in. (15.9 mm) thick or less shall be equal to the thick-times the depth of filling. M b metal over Sia in. thick, it shall be at least one-half the thickness of the material but no 2.8.3 The minimum center-to-center spacing of plug less than 5/8 in.
welds shall be four times the diameter of the hole.
Legend f r Figs. 2.9.1 through 2.10.1 j 2.8.4 The length of the slot for a slot weld shall not exceed r ten times the thickness of the part containing it. The width Symbols forjoint types of the slot shall be no less than the thickness of the part B-butt joint containing it plus 5/16 in. (8.0 mm), preferably rounded C-cornerjoint to the next greater odd 1/16 in. (1.6 mm), nor shall it be T-T-joint greater than 2-1/4 times the depth of filling. BC-butt or comerjoint TC-T- or comerjoint 2.8.5 Plug and slot welds are not permitted in quenched BTC-butt.T. orcornerjoint and tempered steels.
Symbols for base metal thickness and penetration L-limited thickness-complete joint penetration U-unlimited thickness-complete joint penetration Table 2.7 P-partialjomt penetration Q
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Minirnum fillet weld size for prequallfled joints Symbols for weld types Base metal thickness of Minimum size I-quare-groove thicker par
- jointed (T) of fillet weld
- 2-single-V-groose 3-double-V-groove in. mm in. mm 4-single-besel-groost T41/4 TG 6.4 1/8" 3 5-double-bevel-groove 1/4<T41/2 6.4<Ts12.7 3/16 5 Single-pass 6-single-U-groove 1/2<T43/4 12.7<T419.0 1/4 6 welds must 7-double-U-groove 3/4<T 19.0<T 5/16 8 be used 8-single-1-groove
'Except that the weld size need not exceed the thickness of -
the thinner part joined. For this exception, particular care Symbols for welding processes if not shielded metal are should be taken to provide sufficient preheat to ensure weld S-submerged are welding soundness. G-gas metal are welding
" Minimum size for bridge applications is 3/16 in. F-flux cored are welding The lower case !ctters, e.g., a b. c. etc., are used to differentiate 2.8.6 The ends of the slot shall be semicircular or shall between j ints that would otherwise have the same joint designation.
have the corners rounded to a rad.us not less than the
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- r. i57 4TTACHMENT B 1
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A Commentary on Structural Welding Code
< -Steel Third Edition s,
Prepared by AWS Structural Welding Committee Under the Direction of AWS Technical Activities Committee Approved by AWS Board of Directors
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ATTACFIMENT B 4 3 Foreword This commentary on AWS DI.1-81, Structural Weld- tended to provide a detailed resume of the studies and ing Code-Steel, has been prepared to generate better research data reviewed by the Committee in formulating understanding in the application of the Code to welding the provisions of the Code.
in steel construction. Generally, the Code does not treat such design consid-Since the Code is written in the form of a specification, erations as loading and the computation of stresses for the it cannot present background material or discuss the Com- purposes of proportioning the load. carrying members of mittee's intent; it is the function of this commentary to the structure and their connections. Such considerations fill this need. ate assumed to be covered elsewhere, in a general build-Suggestions for application as well as clarification of ing code, bridge specification, or similar document. As an Code requirements are offered with specific emphasis on exception, the Code does provide allowable stresses in new or revised sections that may be less familiar to the user. welds, fatigue provisions for welds in bridges and tubular
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- Since the publication of the first edition of the Code, structures, and strength limitations for tubular connections.
the nature of inquiries directed to the American Welding These provisicas are related to particular properties of Society and the Structural Welding Committee has indi- welded connections.
cated that there are some requirements in the Code that He Committee has endeavored to produce a useful are either difficult to understand or not sufficiently speci- document suitab!c in language, form, and coverage lor fic, and others that appear to be overly conservative. welding in steel construction.He Code provides a means it should be recognized that the fundamenta! premise for establishing welding standards for use in design and of the Code is to provide general stipulations applicable construction by the owner or his designated representa-to any situation and to leave sufficient latitude for the tive. De Code incorporates provisions for regulation of l
exercise of engineeringjudgment. welding that are considered necessary for public safety.
Another point to be recognized is that the Code repre- De Cnmmittee recommend 3 that the owner or owner's sents the collective experience of the Committee and while representative be guided by this commentary in appli-some provisions may seem overly conservative, they cation of the Code to his welded stmeture.The commen-have been based on sound engineering practice. tary is not intended to supplement Code requirements, l
The Committee, therefore, believes that a commentary but only to provide a useful document for interpretation is the most suitable means to provide clarification as well and appl cation of the Code; none of its provisions are as proper interpretation of many of the Code requirements. binding.
Obviously, the size of the commentary had to impose some Comments or inquiries pertaining to this commentary or limitations with respect to the extent of coverage. to the Code are welcome. They should be addressed to:
Ris commentary is not intended to provide a historical Secretary StructuralWeldingCommittee, AmericanWeld-background of the development of the Code, nor is it in- ing Society.
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e . 1 ATTACHMENT B Preface It is the intention of the Structural Welding Committee Changes in the commentary from the first edition have to revise the commentary on an annual basis so that ' been indicated by a single vertical line that appears in the commentary on the changes to the Code can be promptly margin immedistely adjacent to the paragraph affected.
supplied to the user. In this manner, the commentary Changes to tables and figures, as well as new tables or will always be current with the edition of the Structural new figures, have not been so indicated.
Welding Code-Steel with which it is bound.
(9 251
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] ATTACHMENT B Commentary on .
Structural Welding Code-Steel
- 1. General Provisions Note: Alf references to numberedparagraphs. tables, andfigures, unless otherwise indicated, refer to paragmphs, tables, orfigures in A WS DIJ, Structural Welding Code-Steel. References to paragraphs, tables, or figures in this commentary are prefixed with a C. Elence, Fig. 8.8.5 is in AWS DJJ, while Fig. C8.8.5 is in this commentary.
1.1 Application nished in the as rolled condition. The Engineer should recognize that surface imperfections (seams, scabs, etc.)
The Structural Welding Code, hereinafter referred to as acceptable under A6 and A20 may~ be present on the ma-the Code, provides welding requirements for the construe- terial received at the fabricating shop. Special surface t'; tion of steel structures, it is intended to be complementary finish quality, w hen needed in es-rolled products. should with any general code or specification for design and con- be specified in the information furnished to the bidders.
struction of steel structures.
His Code was specifically written for use in the con- 1.3 Welding Processes struction of buildings, bridges, or tubular structures, but its provisions are generally applicable to any steel structure. Certain shielded metal are, submerged arc. gas, metal When using the Code for other structures, owners, arc (excluding the short circuiting mode of metal transfer architects, and engineers should recognize that not all of across the arc), and flus cored are welding procedures in its provisions may be applicable or suitable to their conjunction with certain related ty pes of joints have been particular structure. However, any modifications of the thoroughly tested and hase a long record of proven satis-Code deemed necessary by these authorities should be factory performance.These w eldmg procedures and joints clearly referen ;cd in the contractual agreement between are designated as prequalified and may be used without the owner and the contractor.' tests orqualification (see 5.1 and 5.2).
Prequalified provisions are given in Section 2. Pre-qualified Joint Details; Section 3. Workmanship; and 1.2 B3Se Metal 2 Section 4, Technique. Section 4 includes welding pro-cedures, with specific reference to preheat. filler metals, The ASTM A6 and A20 specifications govem the de-livery requirements for steels, provide for dimensional ctre syze, and omer penknt pquirements. Addi-Ii "*l requirem nts f r prequalif ed jo, m ts m tubular con-tolerances, delineate the quality requirements, and out- .
struction are given in Section 10.
line the type of mill conditioning. The use of prequalified joints ar..! procedures does not Material used for structural applications is usually fur. necessarily guarantee sound welds. Fabrication capability is still required together with effective and hnowledgeable
- 1. As uwd in this commentary, contractor desigrates the pany responsible for performing the welding under the Code. The welding supervision " '-tistently produce sound wc!ds, term is used collectisely to mean contractor. fabricator erector, ,
The Code does s.n 'it the use of any welding manufacturer, etc. process. It also imposes o i Wtation on the use of any other type of jont; nor does it impose any procedural re-
- 2. Since all steel specifications approved by the Code for use
) in buildings, bndges, and tubular structures are listed in 10.2, the general prmisions for apprmed base metals will be dis-cussed in C10.2. As an exception, specific provisions appli.
strictionr on any of the weldmg processes. It provides for the acceptar.ce of such joints, welding processes, and procedures on the basis of a successful qualification by the contractor conducted in accordance with the requirements cable only to buildmgs or bridges are discussed in C8.2 or C9.2 respectively. of the Code (see 5.2).
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.i k _ . __-__- - _ _ - -- ._ __ . _ _ _ _ . . -
ATTACHMENT B
- 2. Design of Welded Connections 2.1.3 The engineer preparing contract design drawings 2.7.1 Minimum Fillet Weld Sizes for Prequalified cannot specify the dept'; of groove (S) without knowing Joints. The Code specifies the minimum fillet weld size the welding process and the position of welding. ne Code and requires that this size be made in a single pass, his is explicit in stipulating that only the effective throat (E) provision is intended to ensure sufficient heat input in is to be specified on design drawings for partialjoint pene- order to reduce the possibility of cracking in either the tration groove welds (2.1.3.1). This allows the contractor heat affected zone or weld metal, especially in a restrained to produce the effective throat by assigning a depth of joint. The minimum size applies if it is greater than the preparation to grooves shown on shop drawings as related size required to carry design stresses.
to his choice of welding process and position of welding. He intent of Tab!c 2.7 is further clarified as follows:
De root penetration will generally depend on the angle Base metal thickness of 3/4 in. (19 mm) and under are subtended at the root of the groove in combination with the exempt from preheat in accordance with Table 4.2. Should root opening, the welding position, and the welding pro- fillet wc!d sizes greater than the minimum sizes be re-cess. For joints using bevel- and V groove wc!ds, these quired for these thicknesses, then each individual pass of factors determine the relationship between the depth of multiple-pass welds must represent the same heat input preparation and the effective throat for prequalified partial per inch of weld length a provided by the minimum fillet joint penetration groove welds. size required by Table 2.7.
2.5 PartialJoint Penetration 2.8 Plug Welds and Slot Welds Groove Welds Plug and slot welds conforming to the dimensional A partial joint penetration groove weld has an unwelded requirements f 2.8, welded by techniques prescribed in Appendix A, and using traterials appmved by 8.2,9.2, or portion at the root of the weld. This condition may also 0.2, am considered prequalified and may be used with-exist in joints wc!ded from one side without backing, and.
ut Performm, g joint welding procedure qualification tests.
therefore, the Code considers them partial joint penetra-tion groove welds except as modified in Section 10 2.9.4-2.10.5 Corner Joint Details.The Code permits an (10.12.4). altemative option for preparation of the groove in one or The unwelded portions are no more harmful than both members for all bevel- and J-groove welds in comer those in fillet welded joints. These unwelded portions joints as shown in Fig. C2.9.4 i constitute a stress faiser having significance when fatigue his provision was prompted by lamellar tearing con-loads are applied transversely to the joint. This condition siderations permitting all or part of the preparation in the
.g is renected in the applicable fatigue criteria. vertical member of .he joint. Such groove preparation llowever, when the load is appbed longitudinally, there reduces the residual tensile stresses, arising from shrinkage is no appreciable reduction in fatigue strength. Irrespec- of welds on cooling, that act in the through-thickness direc-tive of the rules governing the service application of these . tion in a sinF el vertical plane, as shown in prequalified particular grooves, the eccentricity of shrinkage forces in comerjoints diagrammed in Figs. 2.9.1 and 2.10.1. Here-relation to the center of gravity of the material will result fore, the probability of lamellar tearing can be reduced for in angular distortion on cooling after welding. This same these joints by the groove preparation now permitted by eccentricity will also tend to cause rotation in transfer of the Code. However, some unprepared thickness, "a," as axial load transversely across the joint. Therefore, means shown in Fig. C2.9.4, must be maintained to prevent must be applied to restrain or preclude such rotation, both melting of the top part of the vertical plate.This can easily during fabrication and in service. be done by preparing the groove in both members (angle #).
255
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I have read the foregoing affidavit, which was prepared under my personal direction, and it is true and correct to the best of sqy knowledge and belief.
JLL a t JL (Signed) Mark A. Walsh Date:
STATE OF Texas COUNTY OF Dallas On this, the OD ' day of January ,1984, personally appeared Mark A. Walsh , known to me to be the person whose name is subscribed to the foregoing instrinnent, and acknowledged to me that
,.he executed the same for the purposes therein expressed.
Subscribed and sworn before me on the T day of January ,
1984_.
b4 6Mth Nobry Public in and for the State of Texas My Comission Expires: k ll b 4
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