ML18024A978
| ML18024A978 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/19/1979 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 7908270326 | |
| Download: ML18024A978 (171) | |
Text
~ 19Mjgg ENCLOSURE T ~~i ~<~t BROGANS FEKK NUCLEAR PLANT
RESPONSE
TO NRC-OIE BULLETIN 79-02 NRC-OIE Bulletin 79-02, issued March 8, 1979, identified four action items associated with pipe support base plate designs using concrete expansion anchor bolts for holders of construction permits and. operating licenses for nuclear power plants.
The items were as follows:
For pipe support base plates that use concrete expansion anchor bolts in seismic category I systems as defined by Regu1atory Guide 1.29, "Seismic Design Classification" Revision 1, dated August 1973 or as defined in the applicable FSAR.
1.
Verify that pipe support base plate flexibilitywas accounted f'r in Ne calculation of anchor bolt loads.
In lieu of supporting analysis justifying the assumption of rigidity, the base plates should be considered flexible if the unstiffened distance between the member welded to the plate and the edge of the base plate is greater than twice the thickness of theplate. If the base pl"te is determined to be flexible, then recalculate the bolt loads using an appropriate analysis which will account for the effects of shear-tension interaction, minimum edge distance, and proper bolt spacing.
This is to be done prior to testing of anchor bolts.
These calculated bolt loads are referred to hereafter as the bolt design loads.
2.
Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the bolt design load and the bolt ultimate capacity determined from static load tests (e.g.,
anchor bolt manufacturer's) which simu1ate the actual conditions o
installation (i.e., type of concrete and its strength properties):
a.
Four -
For wedge and sleeve type ichor bolts.
b.
Five - For shell type anchor bolts.
3.
Describe the design requirements if applicable for anchor bolts to withstand cyclic loads (e.g.,
seismic loads and high cycle operating loads).
4.
Verify from existing QC documentation that design requirements have been met for each anchor bolt in the following areas:
a.
Cyclic loads have been considered (c.g.,
anchor bolt preload is equal to or greater than bolt design load).
In the case of the shell type, assure that it is not in contact with the back of the support plate prior to preload testing.
b.
Specified design size and type is, correctly installed (e.g.,
proper embedment depth).
If sufficient documentation does not exist then initiate a testing program that wil3.
assure that minimum design requ'ements have been met with respect to subitems a and b above.
A sampling technique is acceptable.
One acceptable technique is to randomly select and test one anchor bolt in each base plate (i.e.,
some supports may have more than one baseplate).
The test should provide verification of subitems a and b above. If the test fails, all other bolts on that base plate should be similarly tested.
In any event, the test program should assure that each seismic category I system wiU. perform its intended function.
The action items are addressed on the following pages.
BROWNS FERRY NUCIZAR PLANT - NRC-OIE BULLETIN 7 -02 Action Item 1 - Flexible Plates AU. anchor plates were assumed rigid in calculating anchor loads for B owns Ferry Nuclear Plant (BFN).
A generic response (Attachment A) comparing the effects of rigid plate assumptions is attached.
At Browns Ferry a higher level of conservatism was applied. to the design of expansion anchors than subsequent research indicated is necessary.
This added conservation more than offsets the maximum'5 percent underestimation of design anchor loads indicated. in the generic response to occur by rigid analysis of flexible plate anchorages.
To the best of our knowledge only self-drilling anchors from ITT Phillips were used.
All designs performed within TVA were based on Phillips recmunendations for anchor capacities in 3500 psi concrete and for limited spacing and edge conditions (Attachment B ).
Some designs performed by Bergen-Patterson used wedge bolts 'based on WEJ-IT anchor capacities.
Action Item 2 - E ansion Anchor Factor of Safet AU. moor piping systems were designed by Bergen-Patterson.
In their designs a minimum safety factor of 8 was applied to self-dril1ing anchors and 4 to wedge bolts.
A few smaH. piping systems were designed by TVA.
On these systems a minimum safety factor of 4 was used.
The ma5or portion of cable tray supports were designed by TVA electrical engineers.
Sampling of computations indicates a variation in applied safety factors from 6.75 to 9.7.
A smaU. number of cable tray supports were designed by TVA civil engineers and for those designs a minimum safety factor of 4 was applied for maximum load combinations.
Electrica1 support systems, instrumentation lines, battery racks etc.,
were designed by TVA civi3. engineers with a minimum safety factor of ( for maximum Wad combinations.
The above safety factors are very conservative considering that current practice allows increased, stress allowables or decreased factors of safety for maximum earthquake loadings and for other unusua1, improbable, or infrequent loading combinations.
Action Item 3 -
clic Loads Seismic and Hi h Fre uenc Ho special design requirements were applied for seismic or for high frequency vibrating loads.
The high amplitude, low frequency, and limited cycles associ,ated with seismic 3.oading do not warrant special consideration.
It was assumed.,
and has been shown, that support problems generated by high frequency system vibrations are quickly identified. under operating conditions and that subsequent corrections of the situationaremore critically related to reducing system vibrations than to corrections of anchorages.
Plant operations havebeen instructed to replace self-drilling anchors with wedge bolts wherever vibrating systems generate anchorage problems.
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Action Item 4 - Testin of E ansion Anchors At Browns Ferry the anchor manufacturer's instruction for installation was the procedure followed.
Prior to August 1973 there were no testing require-ments and inspection was limited to visual determination of proper setting in accordance with manufacturer's recommendations.
Routine testing of anchors beginswith the issuance of BFN Construction Procedure No. BF-107 which was based, on TVA General Construction Specification No. G-32 which was issued. in September 1972 (Attachment C ).
For the remainder of the gob 309 tests were performed representing 2554 anchors fram various systems throughout all three units including reactor, turbine radwaste, diesel generator, and off<<gas treatment buildings.
With the exception of test lot number 8 only one test failure was experienced in the other 299 tests.
In test lot No. 8 there appears to be a conflict between anchor size listed on the drawings and anchor size on the test report indicating the possibility that the 6 failures out of'0 tests were the result of testing 5/8-inch anchors for 7/8-inch proof loads.
A recent inspection of expansion anchor installations at Browns Ferry was made (Attachment D) by members of our design staff to evaluate installations.
In general, most anchorage installations at Browns Ferry are tension type devices for which self-drilling type anchors are best suited.
The report indicated the general condition on the anchorages to be" good.
They did find three instances of anchorage failure which apparently resulted from loads being applied in directions unanticipated by design.
These supports will be repaired although they do not appear in any way to effect system operations.
In conclusion, TVA does not believe that any additional testing of anchorages at Browns Perry is warranted in view of the overall conservations utilized in design; the successful performance of these installations under operating conditions, and the low incident of failure in the in-process testing which was performed.
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Generic Res onse to HRC-OIE Bulletin 7 -02 NRC-OIE Bulletin 79-02, issued March 8, 1979, identified four action items associated with pipe support base plate designs using concrete expansion anchor bolts for holders of construction permits and operating licenses for nuclear power plants.
The 1tems vere as foll.ows:
For pipe support base plates that use concrete expansion anchor bolts in sei.smic category I systems as defined by Regulatory Guide 1.29, "Seismic Design Classification" Revision 1, dated August 1973 or as defined in the applicable FSAR.
1.
Verify that pipe support base plate flexibilitywas accounted for 1n the calculation of anchor bolt loads.
In lieu of supporting analysis Justifying the assumption of rigidity, the base plates should. be considered flexible if the unstiffened distance between the member welded to the plate and the edge of the base plate is greater than twice the thickness of'he plate. If the base plate 1s determined to be flexible, then recalcu1ate the bolt loads using en appropriate analysis which will account for the effects of'hear-tension interaction, minimum edge distance, and proper bolt spacing.
This 1a to be done prior to testing of'nchor bolts.
These calculated bolt loads are ref'erred, to hereafter as the bolt design loads.
2.
Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the bolt design load and. the bolt ultimate capacity determined. from static load testa (e,g.,
anchor bolt manufacturer's) which simulate the actual conditions of installation (i.e., type of concrete and its strength properties):
a.
Four - For wedge and sleeve type anchor bolts.
b.
Five - For shell type anchor bolts.
3.
Describe the design requirements if'pplicable for anchor bolts to witUstand cyclic loads (e.g.,
seismic loads and high cycle operating loads).
4.
Verify from existing QC documentation that design requirements have been met for each anchor bolt in the f'oU.owing areas:
(a)
Cyclic loads have been considered (e.g.,
anchor bolt preload is equal to or greater than bolt design load).
In the case of the shell type, assure that it is not in contact with the back of the support plate prior to preload testing.
(b)
Specified design size and type is correctly installed {e.g.,
proper embedment depth).
If sufficient documenation does not exist, then initiate a testing program that will assure that minimum design requirements have been met with respect to subitcms (a) and (b) above.
A sampling technique is acceptable.
One acceptable technique is to randomly select and test one anchor bolt in each base plate (i.e.,
some supports may have more than one base plate).
The test should provide verification of subitems (a) and. (b) above. Ifthe test fails, all other bolts on that base plate should be similarly tested,.
In any event, the test program should assure that each seismic category I system willperform its intended function.
The fo13.owing response addresses each of the action items generically:
GENERIC RESPONSE TO NRC-OIE BULLETIN 7 -02 Action Item 1 - Flexible Plates Shear-Tension Interaction - There is a distinct difference in the distribu-tion of stress in transferring load from flexible plates to anchors depending on the method, of attachment.
In bolted connections the oversize hole in the plate generally provides space for the lateral plate movement needed to accommodate longitudinal plate deflection.
When the space between bolt and plate is closed at installation or by plate movement the plate transmits shear to the bolt through bearing on the back side of the bolt (see figure 2).
The hole oversize also provides space for rotation between bolt and plate effectively reducing the bending stresses in the bolt which would. otherwise be induced. by the rotation of the plate at the anchor.
Both plate rotation and. anchor displacement are exaggerated in the attached sketches in order to clearly demonstrate the location and dir'ection of principal anchor loads.
In the bolted connection "VR" is the horizontal component of the resultant force of'he plate on the nut and VS is the shear induced in the bolt due to plate movement in excess of the installed.
space between bolt and plate.
V acts on the compression face of the bolt and. can Nary in magnitude without effecting significantly the rotation of the bolt,.
The rotation "f5" of the plate depends on the type of load application as well as plate flexibility. For tensile loading (without bending) the plate deflects essentially as a cantilever and the maximum plate rotation at the anchor can be expressed as:
where:
"e" is the distance from attachment to bolt "t" is the plate thickness "fs" is the bending stress 5n the plate "Es" is the modulus of elasticity of'teel
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Graphically (see figure 3) it can be shown that for approximately the same anchor displacement and plate bending configuration {anchor tensile stress) that any rotation of the attachment due to applied moments will directly reduce plate rotation at the anchor. It also shows a reduced overall displacement
(~H versus A T) and reduced shear in the anchor
{ASM versus ~ ST).
Xt thus appears that for flexible plates the combined.
- tensile, shear, and. bending stresses in the anchor are more severe under direct tensile loading than with attachments sub)ected to bending.
The combined stress condition in anchors is more severe in welded connections than in bolted connections because there is no oversize hole to reduce shear in the anchor and maximum stresses for both shear and tension occur at the same location as shown on the attached sketch.
Results of tensile tests with welded stud anchors attached to flexible plates are shown in figure 4.
They indicate a reduced capacity for plate flexibilityof the following:
where:
"e" is the shortest distance from the centerline of the anchor to the edge of the attachment "t" is the thickness of the attachment plate.
~ w Similar tensile tests have not been performed. to date with bolted connec-tions; however, comparative performance of bolted connections and welded connections of cantilever attachments shoM; a distinct difference in failure tendencies at anchor stresses appxoaching or exceeding minimzn tensile strength requirements.
Mhen the angle of rotation at the anchor is large, due to plate yielding, the displacement of the anchor is a significant factor in the ductility of the anchor and its ability to deve1op maximum tensile capacity.
Anchors with large displacement capacities do not appear to be effected. by the stress combinations.
n Action - Prying action is dependent on (1) anchor displacement, 2 plat rotation at the anchor, (3) plate thickness, and (4) the distance from anchor to edge of plate.
From the previous discussion and the attached calculations (Attachment 1), it is evident that prying action is more severe in direct tensile attachments than in moment attachments.
If the plate has been proportioned in thickness to meet noxmal AISC allowables, and, the edge distance is restricted to approximately two plate thicknesses or two anchor diameters then prying action willbe so small as to be inconsequential in the calculation of anchor stress.
For a given anchor displacement, plate
- rotation, and plate thickness maximum prying action is associated with a specific edge distance.
This edge distance may be varied one to two plate thicknesses, however, without significantly effecting prying action.
C ression Transfer - The location of the resultant compressive force in a manent connection controls the resisting moment arm of the anchorage.
It is, in turn, controlled by base rotation and plate flexibility. Base rotation is affected primarily by displacement of the anchor and secondly
by plate flexibilityas long as plate stresses remain elastic. Ifplate yielding in the compression zone precedes anchor yielding then the center of'ravity {CG) of the compressive force will shift toward the compressive flange of the attachment.
If anchor yielding, or inelastic displacement, precedes plate yielding, then the CG willmove toward the compressive edge of the plate.
The calculations
{Attachment 1) for location of the CG of the compressive force assume the location occurs at the point where the plate rotation balances the rotation of the attachment without regard to any compressive deformation of the concrete.
{The confined state of the concrete will limit compressive defoxmation in the plane of the anchorage to extremely smsl3. values and can be conservatively ignored.)
Anchor Dis lacement - Anchor displacement is dependent on strains in the concrete as well as in steel and on any slip characteristics associated with a specific type and size of expansion anchor.
In the elastic stress range the effective tensile modulus of elasticity of'nchors appears to
'be less than half of the steel modulus.
All expansion anchors produce plastic or inelastic concrete strains in the process of setting expansion mechanisms during installation.
Inelastic strains may also occur at the heads of embedded. bolts as a result of high instaLLation torques.
This plasticity on inelasticity does not effect the elastic displacement properties of the anchor under load; however, because a higher load than the setting load. or installation torque load must occur before any additional plastic displacement of the concrete occurs.
The plastic deformation associated with installation does however effect the amount of preload remaining in the system.
All anchor systems exhibit a short texm installation stress loss of 25 to 30 percent during the fixst day or two following installation and a permanent stress loss of approximately 50 pex cent.
The strain charactexistics of the concrete during installation torque or setting of expansion anchors are affected by the strength of concrete at installation, the depth of anchor head or expansion mechanism below the surface ~and the local density of the concrete atthat point.
Measurements of torque versus anchor stress for embedded. bolts, grouted-in bolts, and wedge bolts in two distinctly different concretes clearly show that torque and anchor load vary significantly with the concrete and anchor type (see figure 5).
Shell-type expansion anchors cannot be effectively preloaded by torque because the attachment plate limits the anchor displacement.
For these anchors the maximum load they see prior to service loading is the installation load created
'by setting the expansion mechanism.
There is, therefore, considerable variation in the load producing nonlinear dis-placements with these anchors; hm~ver, the general level of service load allowables is established to produce elastic displacements with nominal concrete strength under service load conditions.
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Wh the applied, load. exceeds the inst,a1lation setting or torque load in the anchor, then nonlinear displacement wiH. occur.
The slope ofthe loa-d-
. displacement curve in the nonlinear range depends on the type of anchor and strain characteristics of the concrete.
Since anchor displacement directly affects the location of the CG of the compression, the type of anchox has s direct effect on anchor stress.
The ultimate capacity is also directly related to the displacement capacity of the anchor.
5 stress in the first line of'nchors beyond the tensile flange of the attach-ment.
This contrasts with load transf'er through xigid plates which produces maximum stress in farthest line of anchors.
With flexible plates, load transfer to the second and third lines of anchors depends on the displacement of each preceding line of anchors, the spacing of anchors, and. plate stiff'-
ness.
Anchor spacing is limited by anchor depth and capacity to preclude failure of the concrete.
(See anchorage requirements in TVA Design Standar DS-C6.1 for Concrete Anchorages,.)
A flexible plate analysis 0
an anc 0
f anchorage with more than one line of tensile anchors must balance plate deflection at each anchor line with anchor displacemen
.t Anchor e Desi
- Most anchorages have essentially been designed as rigid connections.
Plate flexibilityhas generally been considered only to the extent of proportioning plate thic1messes to meet AISC stress allowables.
The foU.owing comparisons have been made between xigid analysis
- snd, flexible analysis to determine the effect of plate flexibilityon anchor stress.
Plate flexibilityhas no influence on the calculated load of anchorages sub)ected to tensile loading without bending and, therefore, the focal.owing comparison is made for moment connections only.
In most cases anchorages are standardized to be typical for a number of different size attachments of varying cantilever spans.
(Practically all moment connections are of the cantilever type.)
Designs are, therefore,
- based, on maximum loading conditions and maximum attachment size to 4e utilized. with the typical anchorage.
In this (or any other type anchor), the concern for underestimating anchor load by rigid analysis shou1d be for the maximum attachment size corresponding to a given anchorage configuration.
Ifboth attachment and anchorage are designed for the same loading conditions, then the stress allowables in the anchorage should be based on fliLLdevelopment of the attachment.
If the anchor has sufficient displacement capacity at ultimate loading then plate flexibilitywill not xeduce capacity and will actually increase capacity where there sre two lines of tensile anchors beyond the attachment by allowing for equal h
displacements at both lines of anchors.
Since designs are based on service load, or factored load allowables and not on ultimate capac y,
cit full development of the attachment, requires that the safety factor of the anchors equalsor exceedsthst of the attachment.
Plate f1exibility wi13. effect ultimate capacity ifthe displacement capacity
.of the anchors is not sufficient to provide the needed base rotation to move the CG of the compressive force to the outside edge of the plate.
Shell-type expansion anchors generally fall into this classification.
For this type anchors, full development of the attachment requires that the safety factor for anchor service loading, and factored loading be increased, to compensate for the reduced. capacity of the anchorage.
A conservative minimum ultimate displacement capacity for shell-type expansion anchors is 0.2 inch.
For this displacement capacity there is no reduction in moment capacity because of plate flexibilityfor anchorages meeting the maximum conditions outlined in the following table.
TABLE 1 SELF-DRILL EXPANSION ANCHORS Maximum Anchor Moments Plate Thickness Size Inches Service LoadF Sp ac~in In Tension Toaa1
~Ri ia FIexib1e
~Canacia Inches Inches Kis Kis Kin 34.5 25.5 53 41 85 68 174 146 259 214
+Based on G-32 anchor qualification requirements (Attachment 3).
Faased on TVA Design Standard DS-C6.1 allowables (Attachment 2).
1/2 1/2 9
2 4
156 5/8 5/8 lo.5 2
239 3/4 3/4 12 2
4 382 1
7/8 14 3
8
'86 1-1/4 7/8 21 3
8 1167 For larger plates a rigid analysis willoverestimate capacity of self-drilling anchors as shown in comparison table 2.
The anchor displacement capacity of embed)ed bolts and wedge bolt expansion anchors is sufficient to preclude overestimation of'apacity by rigid analysis as shown in the same cmgarison table.
The use of rigid plate assumptions in the analysis of Q.exible plate attach-ments for bending will generally underestimate load in the anchor under service loading conditions by as much as 25 percent.
Under factored loads the underestimation will generally be fram 15 to 20 percent depending on plate size, anchor type, and displacement characteristics.
Any tensile loading which occurs in con)unction with bending will directly reduce the error in calculating anchor load by effecting the net compressive force in the anchorage and by shifting the CG of the compressive force towards the edge of the plate to more nearly coincide with the location resulting from rigid plate assumptions.
The above numbers also do not consider the allocation of the shearing force producing the bending moment.
Using x'igid plate assumptions, this shear is normally divided equally to all anchors resulting in a direct reduction of the service load or factored load allowables.
This shear is actually taken by friction in the compressive zone of the anchorage or is entirely carried by the anchors in the compression zone which are significantly stiffer than the tensile anchors.
As long as system capacities are 1n balance 1t makes very 11ttle difference in attachment perfozmance whether anchor loads in the service load stress range are overestimated or underestimated by the amounts indicated.
At most, the result is a very sma11 change in system deflections or displace-ments which are of a magnitude significantly less than f'it up tolerances necessary for system installations.
In all cases where flexible plates are used, and a close balance exists between capacities of attachment and anchorages, significant yielding of'he plate willprecede anchorage failure and provide adequate warning afproblems.
This balance is assured by TVA's standard design allowables.
The use of the relatively simple rigid plate assumptions appears to be fully justified considering the consequences and the many f'actors affecting anchor loads.
Action Item 2 - E ansion Anchor Factor of Safet Design allowables for expansion anchor are specified 1n TVA's Design Standard for Concrete Anchorages DS-C6.1 (Attachment 2).
Instal1ation and testing procedures for these anchors are specified, in TVA's General Construction G-32 for Bolt Anchors Set in Hardened Concrete (Attachment 3).
G-32 requires that all expansion anchors be tested to f'ailure in job concrete.
It further requires that the concrete f'r qualification testing be between 3000 and 4000 psi at the time of'nstallation and testing.
Each size and type of'xpansion anchor are required. to meet minimum specified. tensile capacities.
These capacities are based on minimum f'actors of safety applied. to the service load, design allowables specified in DS-C6.1.
If anchors of a given size and type fail to meet the required capacities, then the design allowables for those anchors at that project are reduced to maintain the minimum safety factors.
For service load conditions minimum factors of safety of 4 and. 4.g are applied to wedge<<type and shell-type expansion
- anchors, respectively.
No increase in design allowables is made for capacities in qualification testing which exceed minimum requirements and no increase in design al1owables is made for higher strength concrete.
In general, TVA's qualification requirements are approximately 10 percent less for a given size and. embedment depth anchor than the quoted capacities of most manufacturers.
Actual safety factors are thus generally higher than the minimum specif'ied..
A 60-percent increase in stress allowables is provided for factored load design which 1ncorporates different multiplication factors (individual safety factors) on each type of loading for various combinations of loads.
Individual load factors are principally based on probability of occurrence and accuracy of prediction.
This increase i.'n stress allowables for unusual loading conditions or loading combinations is consistent with all code approaches.
Action Item
- C clic Loads Seismic and Hi Fre uenc System deflections are controlled by maximum anchor loads.
The cycling of loads at lower than installation load, levels willnot increase system deflections.
System deflections will tend. to increase on cycling at maximum anchor loads due to creep and. fatigue of concrete under high localized stress conditions.
At loads equal to maximum design allowables there appears to be no problem in stabilizing deflections for thousands of load cycles.
FLexible plates appear to be beneficial in cyclic testing of anchorages by simulating springs in transferring stress reversals to the anchors.
Anchor bolts are not subject to loosening under low frequency seismic vibrations nor is fatigue failure a likely problem because of the relatively low number of cycles involved,.
No special design requirements, therefoxe, are specified for seismic loading of anchor bolts.
Bolts are subject to loosening under high frequency vibrations and fatigue failure is dependent entirely on the level of load. variation'. If the residual load in the anchor resulting fram installation torque exceeds the maximum vibration 3.oad then no stress change occurs in the anchor due to vibration and. no loosening of the bolt or fatigue failure will occur ~
Shell-type expansion anchors cannot be effectively preloaded by torque and, torquing of the short A307 connecting bolts even to snug tight requirements can result in failure of the installation bolts.
For this
- reason, the tightening of these anchors is restricted to 3./4 turn beyond.
finger tight. If these anchors are toPe subject to vibration then a positive means of fastening is required. to prevent loosening.
A minimum torque is required for installation of aL1 wedge type expansion anchors.
Action Irtem 4 - In-Process Testin of Expansion Anchors I
In-process testing of expansion anchors is specified. in TVA General Construction Specification No. G-32 which has been in force since September 3.972.
Testing frequency is specified in tems of lot sizes and, varies from a maximum rate of' test for lots consisting of less than 5 anchors to a minimum rate of 5 percent of the lot size for lots containing more than 60 anchors.
For shell-type anchors a pull test proof load of 1.5 times the maximum specified. design factored load is required.
Proof load testing of shell anchors is required prior to installation of attachments.
Failure by slip is assumed to occur if the gage on the loading device indicates a drop off or lack of advance-ment of load while the anchor is being strained to the specified proof 3.oad.
Wedge bolt anchors are tested by torque to verify that minimum installation torques were applied..
The minimum embedment depths of wedge<<type expansion anchors is controlled by limiting the minimum length of wedge bolts to the two longest lengths supplied, by manufacturers and requiring in purchase specifications that the longer of the two lengths for each size be marked. on the ends for
'isible identification, Depths are then controlled by restricting the progect1,on of'ach size bolt above the attachment plate.
Records of in-process testing are maintained at all prospects ant reporting of test results to design is required,.
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7 48'LW COMPARISON OF RIGID AND FLEXIBLE PLATE ANALYSIS AT SERVICE LOADING AND AT ULTDfATE CAPACITY Size Tube Section Moments Service Ultimate Load
~Ca acit Thick Width Size Ik Ilk II Ii II Anchors Number Mloments Tensile Service Ultimate Anchors ~Racing Load
~Ca acit
~RI id Flex R~iid Flex Ilg II)
Iig It)
Anchor Overstres Service Percen:
4x4xl/2 114 6x6xl/2 324 BX8x5/8 710 loxlox5/8 1214 10xloxl/2 1040 SELF-DRILL EXPANSION ANCHORS 342 3/4 16 3/4 3
6.5 141 106 629 551 7
972 1-1/4 24 7/8 4
7 0 360 276 1581 1406 17 2130 1-1/2 39 7/8 6
7 876 660 3870 3180 8
3642 1-3/4 '46 7/8 7
7.0 1219 924 5388 4438 31 3120 1-3/4 46 7/8 7
7,0 1219 924 5388 4438 13 e
EMBEDDED BOLT ANCHORS 4x4xl/2 5x6xl/2 6x6xl/2 BxGx5/8 tlx8x5/8 Bx8x5/8 10xloxl/2 114 324 324 710 710 710 1214 342 972 972 2130 2130 2130 3642 3/4 1-1/4 19 1-1/4 17 1-1/2 30 1-1/2 24 1-1/2 23 2
29 3/4 2
3/4 1
2 3/4 1
3 l-l/4 2
1-1/4 8
8 13 8.67 10 18 12 119 94'53 353 338 267 1014 1014 347 273 1023 1023 717 547 2159 2159 772 612 2286 2286 763 585 2232 2232 1469 1197 4335 a4335 21 21 19 30 16 21 1
WEDGE-BOLT EXPAhSION ANCHORS 4x4xl/2 114 4x4xl/2 114 5x6xl/2 324 Sx8x5/8 710 LOxloxl/2 1214 342 3/4 16 342 3/4 972 l-l/4 23 2130 1-1/2 33 3642 1-3/4 40 3/4 2
1 2
1 3
4 1<<1/4 4
120 9o 474 474 8
121'o 465 465 9.5 391 295 1541 1541 9.5 774 600 3068 3000 11.67 1220 939 4840 4549 27 27 10 18 29
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CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6. 1 1.0 General 1.1 This standard governs the design of steel components which transmit 1
forces to concrete.
Wherever possible ductility of the anchorage is assured by limiting capacities such that the failure mechanism will be controlled by the properties of the steel rather than concrete.
When capacities are limited by the tensile strength of the concrete, a ~orking load safety factor of at least four is used.
1.1.1
,,Where loads are limited by the properties of the steel, applicable provisions of the AISC Specifications and Commentary are used.
Where loads are limited by properties of the concrete, applicable provisions of the ACI Standard Building Code are used.
Anchorages to concrete have some peculiarities which differ from the usual design provisions of either standard.
1.1.2 All concrete anchorages are single<<shear connections involving shear transfer through relatively large plates whose dimensions are controlled by bending'tresses, whereas the usual steel connection is a double-shear connection involving shear transfer through relatively small plates sized for tensile loading.
The effect of "long" and "short"
.-- connections and "single" or "double" shear on the shear strength of bolts is discussed in the AISC Commentary.
Research testing by TVA
- confirms the AISC Commentary recommendations for short, single-shear connections.
1.1.3 Bearing provisions of the ACI Building Code are concerned with bear-ing restrictions on exterior concrete surfaces.
Research testing clearly demonstrates those restrictions should not apply to bearing stresses at the embedded heads of anchor bolts.
1.2 Bolts with heads or nuts, or simQ.ar studs or bars, embedded in the concrete when the concrete is placed, or grouted into holes drilled in hardened
- concrete, are termed standard anchors.
Anchors which are expanded laterally against the sides of a hole drilled in hardened concrete are termed e
ansion anchors.
Design load provisions of
. this standard apply only to expansion anchors listed in tables II and III.
Commercially available, predesigned and prefabricated embedments installed prior to concrete placement and which are especially designed for attachment of bolted connections are termed concrete inserts.
Provisions of this standard apply only to the UNCONTROLLED COPY This design standard was prepared by CEB's R&D staff in coordination with CDB's RSD staff.
The requirements of this standard may be supplemented or altered for a given pro)ect by written instructions from the engineer in charge.
CPT>>
9-13-76 ORIGINAI ISSUE:
9 75 REVISION NO:
I DATE REVISED:
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6.1 1.2.1 For standard anchors the heads of studs and bolts provide full anchorage in the concrete equal to the tensile capacity of the bolt or stud, provided the limitations for the combined effects of spacing, embedment
- depths, and cover (or edge distances) are not exceeded.
Where plain or deformed bars are used, equivalent anchorage may be accomplished by threading the end of the bar and using a standard nut of equal or higher strength steel.
Threading of A615 bars is limited to bars of 40,000 psi yield strength.
Plain bars of A449 steel may be threaded irrespective of yield strength.
1.2.2 Anchorages for expansion anchors and concrete inserts are limited by anchor size and the design values herein specified.
1.3 Shear bars shall not be used to transmit shear to any concrete anchorage subject to tensile loading.
Shearing forces shall be distributed to bolts, studs, etc., in accordance with their ability to transmit the combined shear and tensile loads as herein described.
1.3.1 In compression
- members, prestressed anchorages, or anchorages with a substantial minimum compression
- zone, shearing forces may be transmitted through friction (see section 2.2) or by distribution to bolts, studs, etc.
(see section 2.3).
1.4 Steel plates are necessary for transfer of loads at the attachment surface to anchor bolts, bars, or studs.
They should not be used at the embedded head of anchors for the purposes of reduced bearing stresses since their inclusion at this point reduces the tensile capacity of the concrete and does not affect anchorage capacity.
Rl 1.5 The basic procedure for design is:
(1) determine the total area of bolts, bars, or studs required for a given configuration of anchors in accordance with section 2.0, (2) determine the embedment require-ments to limit the tensile stresses in the concrete in accordance with section 3.0, (3) check bearing stress on the concrete surface in accordance with section 4.1, and (4) in the case of flexural members, check shear in the concrete.
1.5.1 Design by this standard may be made under either working stress design criteria or ultimate strength design criteria by use of an appropriate 5 factor or as herein described.
Load factors and loading combinations for use in ultimate strength (or factored load) design are specified by the controlling code or pro)ect design criteria.
2.0 Determination of Embedded Steel Area 2.1 Using conventional "straight line" theory for distribution of stress and strain, proportion the anchorage for the combined bending and direct loads on the base plate, ignoring shear, limiting maximum tensile stresses to gfy (or the maximum allowable tensile load per anchor),
and limiting bearing stresses as herein prescribed.
OR IcINAI. IssUE: 9 8 75 REVISION NO:
1
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6 ~ 1 2.1.1 Determine the resultant tensile load (T) in the anchorage and the resultant compressive force (Cp) under the base plate which are required to balance the imposed loads.
2.2 If the total shear load (V) acting in con5unction with the imposed bending and direct loads is equal to or less than 0.5 Cp for the shear plane between steel and concrete or 0.25 Cp for the shear plane between two steel plates, no additional anchorage steel other than that required for tensile loads is required for shear.
2.3 If the total shear load is greater than described
- above, determine the total area of embedded steel required for combined tension and shear in accordance with sections 2.3.1, 2.3.2, or 2.3.3.
2.3.1 Standard Anchors 2.3.1.1 The total area of steel required for combined tension and shear.
CV+ T st ~f where:
A
~ The total area of steel required.
[The area of steel shall st be the stress area of threaded bolts or bars (see table I of the Appendix) and the full cross-sectional area of welded bars and studs.]
T ~ The total tensile load in the anchorage as a result of combined bending and direct load stresses.
V ~ The total shear load.
f
~ The minimum yield strength of the steel.
f
~ 33 ksi for A307 bolts.
f
~ 44 ksi for welded stud anchors (headed).
y 5 ~ 0.90, where V and T represent ultimate or factored loading conditions.
9 ~ 0.55, where V and T are working loads.
C 1.10 for embedded plates with the exposed surface of the steel plate coincidental with the concrete surface.
C ~ 1.25 for plates with recessed grout pads with the contact surface of the plate coincidental with the concrete surface.
Rl w3 ORIGINAL ISSUE: 9/8 75 REVISION Not 1
ATE REVISEO'.
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS>>C6 ~ 1 C ~ 1.50 for plates fastened to hardened concrete with bolts preloaded to yield.
C 1.85 for plates supported on a pad of grout or mortar with the contact surface of the plate exterior to the concrete surface.
Rl 2.3.1.2 Where shear is directed toward an edge, consult section 3.3 for design requirements.
2.3.1.3 Requirements for Tightening Standard Bolts The following requirements for tightening bolts shall be specified on drawings where applicable.
(a)
No standard bolted connections shall be tightened less than "snug tight."
For bolts larger than 5/8-inch diameter, "snug tight" is herein described as the tightness attained by a few impacts of an impact wrench or the full effort of a man using an ordinary spud wrench.
For smaller bolts "snug tight" is herein described as 1/4-turn-of-the-nut after finger tightening or after the surfaces of attachment plate and concrete are in contact.
Rl (b)
All standard bolted connections sub)ect to vibrating loads shall be preloaded to yield by an additional 2/3-turn-of-the-nut after an initial tightening as described in (a).
Where this cannot be accomplished, some positive means of fastening the nut must be devised.
2.3.1.4 Sleeved connections must be completely filled with grout or mortar prior to installation of the attachment.
Rl 2.3.2 Expansion Anchors 2.3.2.0 Design of expansion anchors is herein limited to the design values and expansion anchors listed in tables II and III.
The anchors divide essentially into two basic types:
(1) expansion shell anchors and (2) wedge bolt anchors.
The design values are primarily influenced by anchor size and embedment depth.
The "shell" anchors are further divided into self-drilling and predrilled types.
The anchor type and size must be specified in accordance with section 2.3.2.5.1.
Rl The engineer in charge may authorize the use of other types of anchors or manufacturers other than those listed in tables II and III, provided the results of tests performed in accordance with ASTM E 488-75 using concrete strengths less than 4000 psi are more than 4 times the service load design values of tables II and III for the same size anchor and minimum embedment depth.
4 ORII INAI ISSVC:
REVISION NO:
Avc RcvIsI:o:
26 6
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6 ~ 1 2'.2ol Expansion shell anchors typically fail the concrete in tension because of the relatively shallow anchor depths, but failure by slip may occur at approximately the same loading.
Load-deflection measurements indicate a progressive splitting of the concrete along the failure cone.
Expansion wedge bolt anchors typically fail by anchor slip.
The pullout force is essentially resisted by steel-on-steel friction of the restraining wedge.
The resultant wedge pressure creates tensile stresses in the concrete, and anchor slip is the result of progressive splitting and spallage of the concrete into the open space below the wedge.
The restraint of the concrete against splitting is primarily a function of the location of the wedge with respect to the concrete surface.
Tables II and III provide the allowables for tension (T) and shear (Vo) for both factored load and service load design.
For anchors spaced farther apart than the minimum spacing
- given, use the tabular values for To in applying section 2.1.
For anchors spaced closer than the minimums, determine To in accordance with section 3.2.
Rl 2.3.2.2 For combined loading determine the tensile load (Ti) in each individual anchor under section 2.1 and distribute shear to each anchor (Vi) by:
VT To TT Vo To QVi> V 2.3.2.3 Where shear is directed toward an edge consult section 3.3 for design requirements.
2.3.2.4 Requirements for Tightening Expansion Anchor Bolts The following requirements for tightening expansion bolts shall be specified on the drawings.
(a)
All bolt connections to "shell" type expansion anchors shall be tightened by 1/4-turn>>of-the-nut after finger tightening or after the surfaces of the attachment plate and concrete are in contacts Rl (b)
All shell type expansion anchors sub)ect to vibrating loads must be tightened as above and provided with a positive means to prevent loosening by vibration.
(c)
All wedge type expansion anchors shall be torqued within the range of values specified in table III unless tests performed on pro)ect concrete establish a more desirable range of values for controlling deflections under service load conditions.
Rl ORIGINAL lSSVC> 9 8 75 nevis>oN No:
1 av ncvisco.
CONCRETE ANCHORAGES General CZVIL DESIGN STANDARD DS-C6. 1 2 ~ 3. 2.5 Requirements for Testing and Designation of Expansion Anchors 2 ~ 3 ~ 2 ~ 5 ~ 1 Designation The following letter designations shall be used on drawings and in specifications to identify the required anchor type.
They are given in the order of descending strength requirements.
Any anchor type of higher strength requirements may be used in place of a lower strength requirement anchor without consulting the engineer.
Rl WB SSD SPD EA Vedge Bolt Anchor Expansion Shell Anchor (self-drilling type)
Expansion Shell Anchor (predrilled type)
Unspecified type 2 ~ 3 ~ 2 ~ 5 ~ 2 Testing (a)
In nuclear plant Category I structures all expansion anchors designated SSD and SPD shall require proof load testing in accordance with General Construction Specification No. G-32.
(b)
In nuclear plant Category I structures, expansion anchors designated WB shall be tested in accordance with General Construction Specif ication No. G-32 ~
The installation shall be considered satisf actory if lift~ff (turn-of-the-nut) does not occur at the minimum torque specified in table III.
Rl (c)
Anchor designation EA shall only be given to "approved" anchors whose design loads do not exceed 2/3 of the minimum allowable values of table II.
Proof testing is not required of anchors designated as EA irrespective of location.
2' '
Concrete Inserts 2.3.3.0 Design of concrete inserts herein designated as "standard" apply only to continuous inserts of "Unistrut" series P 3200 channel or its equivalent.
Rl Design of concrete inserts herein designated as only to continuous inserts of "Unistrut" series with 3/8-by 4-inch long Nelson studs welded to spaced 4 inches on centers.
"heavy-duty" apply Rl channel P 1000 the channel web and They do not apply to any other size channel or type of insert.
2.3.3.1 Failure is limited by either the steel properties of the connecting bolts or by the steel properties of the Modified "Unistrut" except for slip resistance of shearing forces acting along the longitudinal axis of the Unistrut channel.
ORIGINAL ISSUE:
8 75 REVISION NO:
TE REVI EO:
26 76
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6 1 2.3 ~ 3 ~ 1.1 The design of "standard" inserts is limited to one single 1/2-inch bolt connection per foot of channel length.
2.3.3.1.2 For combined tensile and shear forces use the allowable tensile values (To) as given below in applying section 2.1 and determine the number of 1/2-inch connecting bolts (Nb) by:
T
+
V Nb T
V 0
0 Tensile loading is limited by the strength of the channel "lip" for sin le or double bolt connections of 1/2-inch bolts preloaded to a minimum torque of 50 foot>>pounds.
2.3.3.1.3 T
~ 2 kips/bolt for service loads 0
T 3.6 kips/bolt for factored loads 0
Tensile loading is limited by the strength of the 12-gauge metal at the "stud" connection for ~multi le bolt connections of 3 or core 1/2-inch preloaded bolts at 3-inch + spacing.
2.3.3.1.4 T
~ 5 kips/foot of channel for service loads 0
T
~ 9 kips/foot of channel for factored loads 0
Shear loading is limited by the shear strength of the 1/2-inch bolt in a transverse direction to the longitudinal axis of the channel.
2.3.3.1.5 VOT 2 kips/bolt for service loads VOT
- 3. 6 kips/bolt for factored loads Shear loading is limited by the slip resistance of the preloaded connecting bolts in the longitudinal direction of the channel.
2.3 3.1.6 V >
1 kip/bolt for service loads OL VOL 1 ~ 8 kip/bo1't for fac'tol ed loads For shear acting at any angle "5" from the longitudinal axis of the channel:
V
~ 2 kips/bolt for service load 1
OA cosS VOA 3 ~ 6 kips/bo 1t for factored 1oads 1.8 <
OA cos ORIGINAL ISSVti RCVISION No:
ATE RSVI I.Ot
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6. 1 2.3. 3. 2 Requirements for Tightening Bolts The following requirements for tightening bolts shall be specified on the drawings.
Rl All connecting bolts for concrete inserts shall be tightened by a minimum torque load of 50-foot pounds or until a distinct yielding of the lip is detected by decreased resistance to the applied torque.
3.0 Determination of Embedment Re uirements 3.1.0 Standard Anchors Minimum embedment lengths of bolts and bars shall be based on develop-ing 1.25 times the minimum required ultimate tensile strength of the embedded steel by assuming an allowable uniform concrete tensile stress of 3.4 ~fc acting on a pro)ected area bounded by the intersection of 45-degree lines radiating from the heads of the bolts or anchors with the surfaces of the concrete (see figure 4).
When the concrete area beyond the outside perimeter of the bolts is limited, the full tensile capacity of the anchorage may be developed in concentrically located, fully developed reinforcing steel of equal capacity.
Under no conditions shall the lap distance between the bolt head and the mechanical anchorage or the return leg of the reinforcing bars be less than the embedment length requirements for the bolts without an edge condition (see figure 6).
Rl The tensile strength of concrete in a slab or wall is limited by the thickness of the concrete and the out-to-out dimensions of the anchors.
If 45-degree lines extending from the heads of exterior anchors toward the compression face do not intersect within the concrete, then the effective stress area is limited as shown in figure 5.
These embedment requirements may also be applied to grouted-in bolts using either sanded Portland cement or epoxy grouts, provided the drilled hole is approximately 2 times the bolt diameter and the sides of the hole have been roughened and cleaned prior to grouting.
3.1.1 For bolts or anchors spaced further apart than 16 anchor diameters, the minimum embedment length (Ld) can be determined conservatively by the following:
(L
+ m) ~ 14d Fut d
60 where:
Fut L
Embedded length (inches) equal to or greater than 8d d
60'l m ~ Edge distance (inches) equal to or greater than 3d Fut 60 ORIGINAL ISSUE:
8 7
REVISION NO:
1 Yf REVISEO'.
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6.1 d
Bolt diameter (inches)
~
F
~ The minimum ultimate tensile strength of the anchors in ksi ut corresponding to specification requirements.
3.1.2 For bolts or anchors spaced closer together than 16 bolt diameters, the restraining tensile requirements of the concrete of section 3.1 will control the minimum embedment length.
For A36 steel and 3000 psi strength concrete, figures 1 thru 3 of the appendix provide a quick method for determining anchor requirements.
Figure 1 is based on the condition that no anchors are located closer to an edge than the depth of the anchor.
Figure 2 is based on the condition that the principal line of stress anchors is located 3 diameters from a concrete edge.
Figure 3 is based on the condition of two perpendicular lines of anchors located 3 diameters from respective edges.
In using figures 1 thru 3 the total number of tension anchors "n" as ~~~.
(a)
For higher strength steel, multiply the required embedment L
of figures 1 thru 3 by Fut 60 (b)
For higher strength concrete, multiply the required embedment Ld of figures 1 thru 3 by 4
gf 3000 c
{c)
The embedment requirement for edge distances "m" less than L but greater than 3d can be determined conservatively by d
interpolation.
3.1.3 When the anchors must be located closer than the minimum "m" distance to an exposed
- edge, reinforcement must be provided to prevent a blowout cone failure.
For standard anchors the side force at the head of the anchor may be assumed as 1/4 of the anchor capacity.
Ductility cannot be assured without reinforcement
{see figure 7).
As an alternative the yield strength to be used in design may be restricted to the following:
2 3.1.4 Minimum Spacing of Stud Anchors 3.1.4.1 Stud anchors are normally furnished in standard length of approximately 10.5 stud diameters when used for tensile anchorages.
Since the ultimate tensile strength of the stud anchors is approximately equal to that of A36 steel, figures 1 thru 3 can be used to limit the spacing of either single depth studs, or double depth studs where studs are welded on studs.
For a minimum embedment depth of 10.5d or 2ld, the corresponding minimum spacing {r) in terms of stud diameters ORic<Naa. issue~
9 8 75 ncvisio~ ao:
1
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6.1 can be read directly from the figures for a given number of studs (the number of studs "n" should be determined as prescribed in section 3.1.2).
For concrete strengths other than 3000 psi the minimum spacing can be obtained by multiplying the above spacing by fI c
3.2 Expansion Anchors The inclination of the concrete tensile failure angle varies with depth of embedment for embedment depths less than 6 inches.
For expansion anchors the assumed angle of failure g for determining the concrete tensile capacity is given below corresponding to depth of embedment.
The failure Rl surface will be bounded by the concrete surface at which the load is
- applied, and by any intersecting lateral surfaces or failure surfaces of adjacent anchors.
Tensile stresses in the concrete shall be assumed uniform over this projected area and shall be limited to 2.4 ~fc for factored loads and 1.5 ~fc for service loads.
When expansion anchors are spaced closer than the specified minimums of tables II or III, the total limiting tensile anchorage load must be calculated using the above criteria.
Rl 5~28+3
~4L 45 d
3.3 Effect of Edge Distance on Shear Strength 3.3.1 The full strength of bolts, bars, or studs in shear can be utilized when the nearest edge distance "m" is greater than 1.25 times the required embedment "Ld" for full tensile development of standard anchors or greater than 10 diameters for expansion anchors.
m 1.25 Ld 3.3.2 Where shear is directed toward an edge located less than above, sufficient reinforcement must be provided to develop the entire shearing force and located to intersect the plane of potential failure (see figure 8).
Limit the maximum allowable shear in the anchors such that:
(a)
For an anchor spacing (r) less than edge distance "m"
U
~ 4.8 rmJf'or max c
V 3.0 roof'or max c
(b)
For an anchor spacing V
4.8 o ~f'or 2
max U
~30m f'or max C
factored loads service loads greater than "m" factored loads service loads oRIcINaI. Issutf 8
5 RCVISION NO:
V RCVISEO 8
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS C6 ~ 1 4.0 Sizin of Base Plates 4.1 Allowable Bearing Stress 4.1.1 Concrete bearing stress limitations are imposed by the ACI Building Code to assure the integrity of both the supporting concrete and the concrete member transmitting load.
When the member applying load is not a concrete
- member, then the only concern for concrete strength is the integrity of the supporting concrete.
4.1.2 When the supporting concrete is wider than the loaded area on all sides, the concrete confines the bearing area and reduces the splitting tendencies of the supporting concrete.
For building columns the provisions of the ACI 318 Building Code Sections 10.14 and 11.10 apply.
For all other anchorages base plates need only be sized for the shear provisions of Section 11.10 and as outlined below.
4.1.3 When the supporting concrete is a flexural member, then failure is either restricted to a tensile concrete failure acting on a 45-degree line radiating from the loaded area for two-way bending or a diagonal tension failure when one~ay bending controls.
Bearing is thus limited by the shear provision of Section 11.10 of the Building Code.
4.1.3.1 When bearing stress in flexural slabs or walls exceeds the above, then the shear reinforcement must be provided as outlined in Section 11.11 of the Building Code.
4.1.4 There are no bearing restrictions at the heads of standard anchors provided the minimum embedment requirements of section 3.0 are complied with.
4.1.4.1 No bearing restrictions should be applied to the sides of fully anchored bars or bolts subject to shearing forces acting through a steel plate affixed to the bar, bolt, or stud in question.
4.1.4.2 Where anchor plates are used on the back surface of concrete, their only function is to reduce the very high surface bearing stress which would otherwise occur under the head of the bolt.
The effective distribution of stress through the anchor plate is approximately twice the thickness of the plate beyond the head of the bolt.
Anchor plates may be proportioned by assuming a
maximum allowable uniform stress distribution over this area of 6 fc>.
4.2 Special consideration should be given to the effect of large shearing forces and edge distance on the proportioning of base plates.
4.2.1 When a base plate is located near the edge of a rigid support, shear-ing forces will reduce the compressive force required to produce failure and the allowable bearing stress should be reduced.
The following should be used to determine allowable bearing for a shear-ing force "V" acting toward a concrete edge:
RCVISION NO!
ATE RfVIStn!
-11>>
CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6. 1 1/3 A
ii 0
8 ii I
0 85V M+
2b~a 2+2 8
sb )
b i
P W
2b b
fb w O.lf' 1.2f'here A b The area of reinforcing steel under the base plate.
sb b
The base plate dimension parallel to the edge of concrete.
w ~ The base plate dimension perpendicular to the edge of concrete.
e ~ The distance from the edge of concrete to the edge of the bearing plate.
p ~ The total applied compressive load.
When the width of concrete support "Wcs the vidth modifier in the above 2b~e 2
When w is less than e, modify the 2 e+w ia less
- than, change 2b~
Wcs equation to.
b above equation by (2e+w) w 18 4a3 Where service load or working stress design is used, the allowable bearing stresses of section 4.0 should be reduced by 50 percent.
4.4 For sleeved bolts the bearing stress on the area projecting past the sleeve shall be limited to a maximum of 6fc.
The minimum thickness of the overhanging plate or washer at the base of the sleeve shall be equal to the maximum overhang.
-)2-ORIOINaI. Issutt 9 8 75 REVISION Not I
dbTE REvISEot 8 26 76
CONCRETE ANCHORAGES General CZVXL DESEGN STANDARD DS-C6.1 NOTATIONS A
The tensile stress area of a single bolt or anchor.
A Reduced stress area for limited depth.
A
>> The total steel area required for anchorage.
st A
The area of reinforcing steel under the base plate.
sb b
The width of base plate parallel to a concrete edge.
b The width of slab or wall supporting a bearing plate.
s C
The shear coefficient applied to standard anchors which accounts for effects of cutting edges,
- threads, and strength factors.
i Rl C
>> The minimum compressive force expected to occur under the base plate of an anchorage.
d The nominal diameter of an anchor bolt, bar, or stud.
d
>> The depth or thickness of a slab or wall supporting a bearing plate.
B e>> The perpendicular distance from the edge of a base plate to the edge of supporting concrete.
f'he allowable average compressive stress (bearing pressure) under b
a base plate.
f'he specified compressive strength of concrete.
c f
>> The specified minimum yield strength of steel.
y F
>> The minimum specified tensile strength of steel.
ut h>> The thickness of concrete slab or wall.
i Rl L>> The minimum embedded length required to fully develop the tensile d
s treng th of an anchorage.
m The edge distance from the center of an anchor to the edge of concrete.
N The average dimension of the base plate divided by the depth of slab or the thickness of wall.
N The total number of bolts in an anchorage.
b P>> The maximum applied compression load on a base plate.
ORIGINAL ISSUEl 9 8 75 RcvISION No:
1 DATE.'EVISEDl 2
'V<~Q CONCRETE ANCHORAGES General CIVIL DESIGN STANDARD DS-C6.1 NOTATIONS (Continued) r The spacing of multiple anchors.
T The total tensile force in an anchorage as a result of combined bending and direct load stresses.
T The tensile force in an individual anchor.
T The maximum tensile force allowed in an individual anchor.
0 U
The total shear in an anchorage.
V,
V The maximum shear value of an individual anchor without edge effects.
V
~ The shearing force acting on an individual anchor.
i V
The shearing force acting on any angle "9" from the longitudinal OA axis of an insert.
VO The shearing force acting along the longitudinal axis of an insert.
VOT The shearing force acting perpendicular to the longitudinal axis of an insert.
M ~ The base plate dimension perpendicular to the edge of concrete.
Mes
~ The width of concrete support.
~ The capacity reduction factor, normally taken as 0.9 for factored
)Rl load design and 0.55 for service load design.
Also used to designate the angle of applied load. ORIGINAL ISSUEI 8 75 REVISION NOR 1
T REVI EO:
CONCREZE ANCHORAGES General - Appendix CIVIL DESIGN STANDARD DS-C6.1 TABLE I STRESS AREAS OF TKUM)ED BOLTS (UNC Thread Series)
Bolt Diameter Inches 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1-1/8 1-1/4 1-3/8 Net Area (ASN)
S. Inches 0.032 0.052 0.078 0.142 0.226 0.334 0.462 0.606 0'63 0.969 1.16 Bolt Diameter Inches 1-1/2 1-3/4 2-1/4 2-1/2 2-3/4 3-1/4 3-1/2 3-3/4 Net Area (ASN)
ScC. Inches 1 ~41 1.90 2.50 3.25 4.00 4.93 5.97 7.10 8.33 9.66 ORICINAL ISSUE:
8 REVISION Nos l
o TE REvISEO.
8 26 76
) )
) Er
)
~ <
J(
l.
) r, ), )o)))or
~ ~ r TABLE II EXPANSION SHELL ANCHOR DATA Bolt Size in.
Minimum Depth in.
T0 V0 Factored Load Design ki s V0 T0 Service Load Design ki s Nominal Minimum Spacing in.
1/4 5/16 1-3/32 1-5/16 0.70 0.50 0.45 0.30 1.05 0.80 0.65 0.50 2.5 3.5 ACCEPTABLE SSD ANCHORS 3/8 1/2 5/8 2-1/32 2.30 2.20 1.45 1.40 2-15/32 3.10 3.55 1.95 2.25 1-17/32 1.50 1.25 0.95 0.80 4.0 5.0 5.5 Phillips Self-Drill Rawl Self-Drill ACCEPTABLE SPD ANCHORS 3/4 3-1/4 4.40 5.25 2.75 3.30 6.5 Phillips Non-Drill Rawl Steel Drop-in Hilti Hol Hugger 7/8 3-11/16 5.30 7.20 3.30 4.50 7.0 b
Pl(
Pl 0
( Z z
0 NOTES:
(a)
Allowable loads shown above apply only to anchors which are to be proof tested in accordance with Standard Construction Specification No. G-32.
Use two-thirds of the above values in design of anchors which are not to be proof tested.
(b)
Allowable loads apply only for anchors in concrete having a compressive strength of 3000 psi or more.
(c)
Allo~able loads are for predrilled (SPD) anchors.
For self-drilled (SSD) anchors the above values for T may be increased by 20 percent.
0 M
M Q
8 0 00 0
pn 0'
0 0
0 0y TABLE III WEDGE BOLT DESIGN DATA Bolt Size in0 D
Min.
Length in.
1 Min.
Depth Ld 2
Max0 Attachment Thickness in.
T0 V0 Factored Load Design ki s Service Load Design ki s V0 Min.
Spacing Installation Torque ft.-lbs Min.
Max.
1/2 5-1/2 3-1/4 1-1/2 5/8 6
4-1/4 7/8 3/4 8-1/2 6
1-3/4 1
9 7
1 1-1/4 12 9
1-3/4 3.35 3.20 4.40 4.80 6.60 6.65 10.00 10.70 13.10 15.60 1/4 3
1-3/4 1
0.95 0.80 3/8 3-1/2 2-1/4 7/8 1.45 1.90 0.60 0.50 0.90 1.20 2.10 2.00 2.75 3.00 4.20 4.15 6.30 6.70 8.20 9.75 3.0 4.0 5.0 70 9 5 10.5 15 40 70 120 240 400 10 30 60 100 180 360 500 NOTES:
(1)
Depth measured to the bottom of the anchor.
(2)
Longer bolts which are required for thicker attachments must be color coded for identity.
(3)
Maximum projection of the bolt above the attachment after installation should not exceed two bolt diameters.
(4)
Allowable loads are based on concrete having a minimum compressive strength of 3000 psi.
APP ROVED ANCHORS Hilti Kwik Bolt Phillips Wedge Anchor Rawl Stud Bolt We)-It
CONCRETF.
ANC)IORAGES General - Appendix CIVIL DESIGN STANDARD DS-C6 F 1 38 36 SO 28 26 I-24 22 I-w 20 C) a)
I 8 LLI 16 E
I4 Z
I2 IO nap nc6 h+2 EMBEDMENT REQUIREMENTS FOR STANDARD ANCHORS n= No. of Tensil Anchors d= Diam. of Anchors R= Spacing of Anchors Ld = Min. Embed Depth A= 36 Steel f'c = 3000 psl 0
4 5
6 7
8 9
IO II I2 IS I4 I5 R/d SPACING OF HEADED ANCHORS EDGE DISTANCE ~ 1.2 Ld Figure 1
ORIGINAL ISSUE RE'VISION NO:
ATE RCVISCO,
CONCRETE ANCHORAGES General - Appendix CIVI1. DESIGN STANDARD DS-C6.1 48 46 40 38 36 34 CI 32 30 4J 28 26 24 22 20 n,0/
h g 0
Cp EMBEDMENT REQUIR E MENTS FOR STA N DARD ANC HORS n= No. of Tensile Anchors d= Diom. of Anchors R= Spocing of Anchors Ld=Min. Embed Depth A=36 Steel fc<5000 psi l8 l6 l2 l0 4
5 6
7 8
9 l0 l l l2 I3 14 15 R/d SPACING OF HEADED ANCHORS EDGE DISTANCE ~ 3d Figure 2 oa<c>aaL. assur.
9 8 75 acvisio~ rvo:
1 AT RfVISEo.
CONuu;.TE ANCHORAGES General - Appendix CIVIL DESIGN STANDARD DS-C6.1 70 66 62
&54
+
SO LLJ Cl 46 z
o 42 5S 30 O~
Qp C~
n+/y noe EMBEDMENT REQUIREMENTS FOR STAN DARD ANCHORS n= No. of Tensile Anchors d= Diam. of Pn chors R* Spacing of Anchors Ld Min. Embed Depth A=36 Steel fc*5000 psi 26 22 IS I4 IO 4
5 6
7 S
9 IO I I I2 13 I4 l5 16 RAI SPACING OF HEADED ANCHORS EDGE DISTANCE ~ 3d TWO PERPENDICULAR EDGES Figure 3
ORIGINAL ISSUE:
8 75 REVISION NO:
AT R vISEo.
8 6 76
CONCRETE ANCHORAGES General - A endix CIVIL DESIGN STANDARD DS-C6.1 PROJECTED STRESS AREA PLAN Ld BABE OFANCMORAGE~
SECTION TENSILE LOADING AREA LOST 454 PROJECTED STRESS AREA II r
EDGE EDGE PLAN SHIFT IN CQ.
(Ld c*8 (
Vp}
SECTION COMBINED SHEAR AND TENSION EDGE EFFECTS ANCHORAGE PULLOUT CONE DETAILS Figure 4 ORICINAL ISSUE:
RCVISION NO:
AT RE'VISEO:
8
CONCRETE ANCHORAGES General - Appendix CIVIL DESIGN STANDARD DS-C6.1
% EFFECTIVE STRESS AREA EFFECTIVE STRESS AREA
'b (brag-ah)
PLAN QB EFFECTIVE STRESS AREA UP Ld A
A, (a+ay-ah)
EFFECTIVE STRESS AREA A-A STRESS AREA REDUCTION FOR LIMITED DEPTH (A )
AR (a + 2Ld - 2h) (b + 2Ld - 2h)
- REDUCE BY THE TOTAL BEARING AREA OF THE ANCHOR STEEL Figure 5
. oRIGINALIssUe:
9 8 75 ReVISION NO:
1 A
RKVISFOS
s
=
si s
$ %" i' i r
~
I
~ ~
M I
I
=i Ab Fut e
L
~ D m<3dP60 45o Failure Cone C lod 60 Failure Cone SECTION SECT) ON SECTtON Failure Cone Failure Cone 0
B AbFuf As=
4 fy Abfut Aa=-
Cfy 0
O N pXa~
nomina Cover PLAN Figure 6
(Ref. Sect. 3.1.0)
PLAN Figure 7
(Ref. Sect. 3.1.3)
PLAN Figure 8 (Ref. Sect. 3.3.2)
TENNESSEE VALLEYAUTHORITY DIVISION OF ENGINEERING DESIGN GENERAL CONSTRUCTION SPECIFICATION NO.
G-3a FOR BOLT ANCHORS SET XN HARIElKD CONCRETE
@Oggmg cov~
REVISION 0
Rl R2 R4 R5 Date SPONSORED SUBMITTED RECOMMENDED (Sponsor Branch Chief)
CONCURRED SPEC. SECTION APPROVED
{Dir.of Construction)
APPROVEO
{Oir.of En
. Osgn.)
September 1972 Ori nal Si ed b R. E, Bullock O. H. Raine C ~ H, Glam F, P. Lacy P. L. Duncan H. H. Hull J. R. Parrieh 3-28-75 Initiale OHR 9-23-75 4"21-76 Prn
/.
7-21-77
'Wc.
TVA t 0574A (DED 8.74)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE
Title:
REVlSJON LOG G-32 Revision No.
DESCRlPTlON OF REVlSlON Date Approved Revised DED organization names and revised sections 1.2, 6.1, and 6.2 to clarify project office drawings and reporting requirements.
10-73 Revised sections 1.5, 2.1, 2.3, 3.2, 3.3, 4.0, and 5.2 for details.
Revised section 6.1 to send reports to appropriate Design Project Manager.
Added section 3.5.
Made new cover sheet.
Added revision log.
3-75 Revised section 3.2 to eliminate the use of epoxy grout in fire hazard areas.
Revised section 6.1 to require transmittal of anchor test reports to DED for only those anchor lots in which an anchor fails when tested.
Revised section 6.2 accordingly.
Added Attachment A.
9"75 Revised sections 1.2, 1.5, 4.2, and 6.2 to reduce requirements of testing expansion anchors and reporting; section 4.3 to clarify concrete strength for expansion anchors.
4-21-76 General revision to add wedge bolt anchors, nondrilling expansion shell anchors, qualification tests on all types of expansion
- anchors, and to modify other sections accordingly.
Only the significant changes for this revision are noted by revision indications on the pages; previous revision indications are deleted.
Removed Attachment A.
7-21-77 TVA )0534 (OED 9 73)
0
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDF.
TABLE OF CONTENTS Revision Log
~Pa e No.
1.0 GENERAL
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1.2 D~eaeia a
1.4 Reference S ecifications 1.5 Definitions 1"1 l<<l 1".1 1"1 1-2 2.0 MATERIALS
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2-1 3.0 2.1 E
ansion Shell Anchors 2.2 Wed e Bolt Anchors 2.3 Drill Bits 2.4 Bolts 2.5 Portland Cement Grout 2.6 D
-Pack Mortar 2.8 ualification of E ansion INSTALLATION
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Anchors 2"1 2-1 2-1 2-2 2-2 2-2 2-3 2-3 3-1 I>
l~
4.0 5.0 3.1 General 3.2 E
ansion Shell Anchors 3.3 Wed e Bolt Anchors 3.4 Grouted Anchors 3.5 Iocation 3.6 Reinforcin Steel 3.7 E uivalent Anchors TESTS
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4.1 Selection 4.2 Ex ansion Shell Anchors 4.3 Wed e Bolt Anchors REPLACEMENT 3-1 3-1 3-1 3-3 3-4 3-5 3"6 4-1 4-1 4-1 4-2 5-1 5.1 General 5.2 Removin Anchors 5-1 5-1 TVA 10535 (EN DES 5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN A
E TABLE OF CONTENTS (Continued) 6.0 RECORDS AND REPORTS 6.1 General
~Pa e Ne 6-1 6-1 6-1 A~endix A "QUALIPICATIONTESTS FOR EXPANSION SHELL ANCHORS" A~endix B "QUALIFICATIONTESTS FOR WEDGE BOLT ANCHORS" A-1 B-1
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE G" 2
- 1. 0 GENERAL 1.1
~Sco e
This specification prescribes materials and methods for setting threaded anchoring devices for equipment and fixtures into concrete which has previously hardened.
The work includes qualification of anchors, anchor installation procedures, and testing of anchors installed in nuclear plant category I structures.
1.2
~Drawin s Anchors shall be provided according to drawings prepared by or approved by the Division of Engineering Design (EN DES).
Changes I
shall be made only with the approval of the Engineer.
The Division of Construction (CONST) project office shall prepare drawings, or mark half-size prints of drawings prepared by or approved by EN DES; to show the location of and test information on each lot of anchors which require testing.
Drawings will not be required where another system which uniquely and completely defines a lot is adopted and recorded with test information.
The Engineer as used in this specification shall mean the authorized representatives of the Manager of Engineering Design and Construction.
For design considerations, these shall be the Division of Engineering Design acting through the appropriate Design Project Manager or Engineering and Design Branch Chief.
For construction, in general, these shall be jointly the appropriate Design Project Manager or Engineering and Design Branch Chief and the project Construction Engineer or their designated representatives; any deviation from this specification must be agreed to jointly by them.
1.4 Reference S ecifications The latest revisions of the following specifications shall apply where referred to in this specification.
TVA 10535 (EN DES-5.77)
ADCON - PN-025
GENERAL CONSTRUCTION SPECIFICATION FOR BOIT ANCHORS SET IN H RDFNFD C
NC 1.0 GENERAL (Continued) 1.4 Reference S ecifications (Continued)
American Societ for Testin and Materials A 36
- Standard Specification for Structural Steel A 307 - Low-Carbon Steel Externally and Internally Threaded Standard Fasteners C 109 - Standard Method of Test for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or 50-mm cube specimens)
C 144 - Standard Specification for Aggregate for Masonry Mortar E 4SS - Standard Test Methods for Strength of Anchors in Concrete and Masonry Elements Tennessee Valle Authorit General Construction Specification No. G-2 for Plain and Reinforced Concrete (hereinafter termed G-2)
Civil Design Standard DS-C6.1, Concrete Anchorages (hereinafter termed Design Standard) 1.5 Definitions Vherever the words defined below appear in this specification, they shall have the meanings here given.
Attachment.
A piece of equipment or fixture to be fastened to hardened concrete.
Anchor.
A threaded device for fastening attachments to hardened concrete (distinguished herein as expansion anchors and grouted anchors).
Ex ansion Anchor.
An anchor which expands laterally in a drilled hole to resist pullout.
Ex ansion Shell Anchor.
An expansion anchor which consists of an internally threaded, externally slit tubular shell with a single cone expander that causes the shell to expand laterally against the sides of a drilled hole.
Self-drillin Ex ansion Shell Anchor.
An expansion shell anchor which uses the shell for drilling the hole (designated herein an~ on the drawings as SSD).
1-2
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCH S
S 1.0 GENERAL (Continued) 1.5 Definitions (Continued)
Nondrillin E
ansion Shell Anchor.
An expansion shell anchor which is placed in a predrilled hole (designated herein and on the drawings as SPD).
Wed e Bolt Anchor.
An expansion anchor which consists of an externally threaded bolt with a split ring or separate wedge pairs that expand laterally against the sides of a predrilled hole when the bolt is torqued, and which will expand further if the bolt is partially extracted from the hole by a tensile load (designated herein and on the drawings as WB).
Grouted Anchor.
An anchor which consists of a headed bolt or a threaded rod with an end nut, placed in a drilled hole, the remainder of which is filled with grout or dry-pack mortar.
~Cate o
I.
Nuclear plant equipment and structures so classified in the plant Safety Analysis Report.
(Category I is class I in nuclear plants under construction at the time of original issue of this specification.)
Lot.
A number of anchors in a nuclear plant category I structure which are considered as a group for testing purposes.
A lot shall consist of the anchors installed by a specific crew either in a specific location in the plant or over a period of time.
If the lot is defined on the basis of anchor location, the lot shall consist of:
(a) the anchors for a single piece of equipment having three or more anchors, (b) the anchors on a floor, wall, or ceiling which has conveniently indicated boundaries, or (c) a long line of anchors on a floor, wall, or ceiling for a continuous structure such as a cable tray. If a lot is defined on the basis of anchors installed over a time period, the maximum time period shall be 2 weeks, each crew shall apply a unique identification mark on the concrete adjacent to the anchor or to a piece of equipment with more than one anchor, and a
record of all anchor installations shall be kept.
Regardless of the basis for defining the lot, anchors of a different type or brand shall be considered in separate lots and sufficient records shall be kept to ensure that all anchors are assigned to a lot.
~Sli During testing, an expansion shell anchor shall be considered to have exhibited slip if the gage on the loading device indicates a dropoff or lack of advancement of load while the anchor is being strained.
1-3 TVA 10535 (EN DES.5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE G-2 1.0 GENERAL (Continued) 1.5 Definitions (Continued)
A roved Permitted Re uired.
Wherever such words are used in this specification, they shall be held to refer to the orders or instructions of the Engineer unless another meaning is plainly intended.
Called For.
Wherever these words are used in this specification, they shall mean called for by drawings, memorandums, or separate specifications issued by the Division of Engineering Design.
1-4
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 2.0 MATERIALS 2.1 E
ansion Shell Anchors G-2 Unless otherwise called for, expansion shell anchors shall be used only for bolts 7/8-inch or smaller in diameter and shall conform to the requirements of section 2.8.
2.2 Wed e Bolt Anchors Unless otherwise called for, wedge bolt anchors shall have the following diameters and minimum lengths:
Diameter (in.)
1/4 3/8 1/2 5/8 3/4 1
l-l/4 Minimum Length (in.)
Regular 3
Long 3-1/2 5-1/2 6
8-1/2 5
7 8"1/2 10 9
12 12 Long wedge bolt anchors shall be color-coded or stamped in accordance with section 3.3.
(Minimum bolt lengths and color-coding or stamping of long anchors is required to permit in-process inspection of anchor embedment by measurement of bolt projection.)
The bolt material for wedge bolt anchors shall have a minimum yield strength of 70,000 psi.
Wedge bolt anchors shall conform to the requirements of section 2.8.
2.3 Drill Bits The manufacturer of nondrilling expansion shell anchors and wedge bolt anchors shall specify the maximum diameter drill bit (to the nearest 0.001 inch) that is to be used for the installation of each size anchor.
Before its initial use, the diameter of each drill bit shall be checked to assure that it does not exceed the maximum.
For qualification tests, drill bits shall have a diameter within 0.002 inches of the maximum.
The diameter of the bit shall be checked before drilling the hole for installation of each test anchor.
2-1 TVA 10535 (EN DES.5.77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOIT ANCHORS SET IN HARDENED CONCRETE 2.0 MATERIALS (Continued) 2.4 Bolts Unless otherwise c'alled for, all bolts except wedge bolt anchors shall conform to ASTM A 307, Grade A, or shall be made of rods which conform to ASTM A 36, with nuts which conform to ASTM A
- 307, Grade A.
Rods shall have UNC threads on both ends with a nut on the embedded end which is tack welded in place.
2.5 Portland Cement Grout Portland cement grout shall be a job-proportioned mixture of portland cement, fine aggregate, and water, with or without admixtures; or a commercial premixed portland cement-based grout and water.
All material for job-proportioned grout shall conform to the requirements of G-2, except as modified below.
Cement shall be type I, II, or III.
Fine aggregate shall conform to ASTM C 144 except that no more than 10 percent shall pass the No.
100 sieve, or to G-2 except that all material which will not pass the No.
16 sieve shall be discarded.
Job-proportioned grouts shall have a maximum ratio of water to cement of 0.5.
The fine aggregate shall be added in as great a quantity as will still provide adequate flowability.
Admixtures, if used, shall reduce bleeding and cause a slight expansion of the grout before hardening.
Admixtures shall be added in the quantity recommended by the manufacturer.
Premixed grout shall be Five Star grout, U.S. Grout Corporation, New Greenwich, Connecticut; Embeco 713 grout, Master Builders, Cleveland, Ohio; or equal.
Premixed grout shall not contain oxidizing catalysts.
Premixed grout shall have water added in the quantity recommended by the manufacturer for a flowable or pourable consistency.
2.6 D
-Pack Mortar Dry-pack mortar shall be a j ob-proportioned mixture of portland
- cement, fine aggregate, and water.
All materials for dry-pack mortar shall conform to G-2 except as modified below.
Cement shall be type I, II, or III. Fine aggregate shall conform to ASTM C 144 except that no more than 10 percent shall pass the No. 100 sieve, or to G-2 except that all material that will not pass the No.
16 sieve shall be discarded.
2-2
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 2.0 MATERIALS (Continued)
Dry-pack mortar shall have a ratio of fine aggregate to cement of 2.5 to 3.0 by weight.
The mortar shall contain only sufficient water to result in a mixture that will stick together on being molded into a ball by a slight pressure of the hands without exuding water, but leaving the hands damp.
Epoxy grout shall consist of an epoxy binder and ovendried fine aggregate.
The epoxy shall be a two-component modified system formulated and recommended by the manufacturer for grouting of anchor bolts.
The epoxy shall be suitable for bonding to wet surfaces unless holes are to be dried before grout placement.
Fine aggregate shall be added to the epoxy in sufficient quantity to result in adequate flowability.
Fine aggregate shall be graded standard sand for ASTM C 109 cement tests, sandblast
- sand, or other fine aggregate recommended by the epoxy manufacturer.
2.8 uglification of E ansion Anchors 2.8.1 General gualification tests in accordance with the methods of Appendix A or B shall be performed prior to the initial use of each size and brand of expansion anchor.
For each major project, qualification tests shall be performed on anchors installed in project-placed concrete.
Anchors for use on smaller projects may be qualified on the basis of tests performed at a major project or at Singleton Materials Engineering Laboratory.
Before qualification tests are made, the results of static tension tests performed by an independent testing laboratory shall be obtained from the manufacturer.
The tests shall be in accordance with ASTM E 488 and shall indicate that the requirements of section 2.8.2 will be met.
The anchor capacities listed in manufacturers catalogs may be used only if it can be determined that proper embedments, concrete strength, and test methods were used.
Information on the mechanical properties and applicable specification designations of the anchor
- materials shall also be obtained from the manufacturer.
2-3 TVA )0535 tEN OES-5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE G-32 2 '
MATERIAI,S (Continued)
A specific brand and size of expansion for use shall have an average ultimate
'determined by Appendix A or B equal to following:
anchor to be qualified tensile capacity as or exceeding the Minimum Ultimate Tensile Ca acities (Ki s)
Anchor ape Size 1/4" 5/16" 3/8" 1/2" 5/8" 3/4" 7/8" 1"
l-l/4" SPD SSD WB 2.0 2.4 2.4 2.9 4.3 6.5 8.8 12.4 14.9 3.5 5.1 7.8 10.5 14.9 17.8 3.6 8.4 11.0 16.8 25.2 32.8 If the average ultimate tensile capacity for a size and brand of anchor fails to meet the requirement, but the average of the two larger ultimate tensile capacities does meet the requirement, a retest using new anchors may be performed.
An anchor shall be disqualified if it fails to meet the ultimate tensile capacity requirement, ifit is difficult to install, if installation results in damage to the concrete or anchor, or for any other reason which significantly affects production or inservice performance.
2.8.3
~Re orts A complete report of all expansion anchor qualification tests shall be made.
The report shall include the individual test reports detailed in Appendices A and B.
One copy of the report shall be sent to the design representative of section 1.3 and four copies to the construction representative as soon as the report is completed.
2-4
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE G-3.0 INSTALLATION 3.1 General Unless otherwise called for, anchors shall be installed only in concrete with a compressive strength of at least 3000 psi and shall not be installed in concrete block or masonry mortar.
Expansion anchors shall be installed through topping or cladding only if expansion shell anchors are not subjected to shear loading and are completely embedded in structural concrete and if, for wedge bolt anchors, the topping or cladding thickness is considered to be a portion of the total attachment thickness.
When grouted anchors are installed through topping or cladding, the required embedment shall be from the face of structural concrete.
The holes drilled for all types of anchors shall be carefully cleaned of all dust and debris before installation of the anchor.
The anchor type installed shall be that designated on the drawings or the equivalent permitted by section 3.7.
The anchor designation EA on the drawings indicates that reduced allowable loads were used and that any SSD, SPD, or WB anchor of the indicated size which conforms to sections 2.1 or 2.2 may be installed.
3.2 E
ansion Shell Anchors Expansion shell anchors shall be installed according to manufacturer's instructions.
The holes for nondrilling expansion shell anchors shall be drilled with drill bits conforming to section 2.3.
In no case shall the top of the installed anchor protrude from the concrete
- surface, nor shall it be recessed more than 1/8 inch.
The ASTI A 307 bolt installed in an expansion shell anchor shall be of such length that it will extend at least one nominal bolt diamter into the anchor after tightening.
The bolt shall be tightened not less than 1/8 turn or more than 1/4 turn after the nut, washer, attachment, and concrete have come into intimate contact.
3.3 Wed e Bolt Anchors Wedge bolt anchors shall be installed in holes with a minimum depth equal to the bolt length minus the thickness of the attachment.
The maximum hole depth shall not exceed 2/3 of the thickness of the concrete member in which the anchor is being installed.
The drill bits shall conform to section 2.3.
3-1 TVA 10535 (EN DES-5 77)
0
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 3.0 INSTALLATION (Continued) 3.3 Wed e Bolt Anchors (Continued)
Unless otherwise called for, wedge bolt anchors shall not be installed through attachments with thicknesses at the point of anchorage greater than the following:
Diameter (in.)
1/4 3/8 1/2 5/8 3/4 1
l-l/4 Thickness (in.)
Regular Long 1
7/8 1-1/2 7/8 1-3/4 1
1-3/4 2-3/8 3
3-3/8 3"1/4 4
(Note:
The maximum attachment thickness does not increase uniformly with anchor diameter due to non-uniform changes in embedment and anchor length).
Long wedge bolt anchors may be used for any anchorage where a
regular anchor would be acceptable provided the maximum hole depth is not exceeded.
Where the attachment thickness is greater than the maximum allowed for regular wedge bolts, long wedge bolt anchors shall be installed after being identified for inspection either by painting the exposed end a bright color or by stamping the bolt length or a code for the bolt length into the exposed end of the bolt.
Before insertion in the hole, and with the washer in place, the nut shall be screwed onto the bolt until the end of the bolt is appzoximately 3/4 of the way through the nut.
The assembled wedge bolt shall then be inserted in the hole through the attachment and hammered down until the nut, washer, and attachment are in intimate contact.
The anchor shall be tightened to a minimum of the following torque or the installation torque determined by Appendix B, whichever is greater.
Bolt Diameter (in.)
1/4 3/8 1/2 5/8 3/4 1
l-l/4 Torque (ft.-lbs.)
5 15 40 70 120 240 400 Torque shall be read while the nut is in a tightening motion.
After tightening wedge bolt anchors, the projection of the anchors above the attachment at the point of anchorage shall not exceed the following:
Bolt Diameter (in.)
1/4 3/8 1/2 5/8 3/4 1
l-l/4 Haximum Projection (in.)
1/2 3/4 1
l-l/4 l-l/2 2
2-1/2 3~2
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 3.0 INSTALLATION (Continued) 3.4 Grouted Anchors Grouted anchors shall be installed in drilled holes which have a diameter between two and three times the nominal bolt diameter.
The bolt shall be embedded to the depth called for but not less than 8 nominal bolt diameters.
Hole sides require a small visual roughness.
If none is apparent, as may occur with core drilling, a chisel or equivalent shall be used to make two or more shallow grooves on opposite sides in approximately the bottom half of the hole.
Holes for epoxy grouted anchors shall be dry unless the epoxy manufacturer specifically permits grout placement into damp holes.
Holes for epoxy grouted anchors shall be primed with a coat of neat epoxy and the epoxy grout shall be placed while the prime coat is still tacky.
Unless specifically called for grouted anchors may be set using either portland cement-based grout, dry-pack mortar, or epoxy grout conforming to section 2.0.
(Where the EN DES organization responsible for the design of equipment or fixtures considers fire hazard significant or expects operating temperatures greater than l20 F, the drawings will specify that epoxy grout shall not be used.)
Epoxy may be ignited by welding of metal in contact with the epoxy.
Where grout is used to set the anchor and the grout will not flow from the hole, the hole shall be filled approximately half full of grout and the bolt inserted by twisting and working in and out to ensure elimination of all voids.
The remainder of the hole shall then be filled with grout, the bolt shall be fixed in position, and the grout shall then be cured.
Where grout will flow from the hole, the hole and anchor shall be fitted with a cover plate of wood or other material through which the grout can be pressure injected.
For vertical or upward sloping holes, a small air vent pipe shall be placed to the highest elevation in the hole and grout injected through a port in the cover plate.
For horizontal or downward sloping holes, an air vent shall be placed through the cover plate at the highest elevation in the hole and grout shall be injected through a pipe to the lowest elevation of the hole.
When grout flows from the vent, both the port and the vent shall be positively closed off.
The cover plate shall be coated with a bond-preventing material on the grout side and shall be removed after the grout has cured.
Where dry-pack mortar is used to set the anchor, the bolt shall rest against the bottom of the hole or if the hole was drilled too deep, mortar shall be placed in the hole and thoroughly compacted with the head of the bolt until the desired bolt TVA 10535 (EN OES-5-71)
GENFRAL CONSTRUCTION SPECIFICATION FOR BOI.T ANCNORS SET IN 1{ARDENED CONCRETE 3.0 INSTALLATION (Continued) 3.4 Grouted Anchors (Continued)
G-2 embedment or projection is achieved.
Mortar shall then be placed uniformly around the bolt and thoroughly compacted in layers which have a compacted thickness of about 3/8 inch.
The mortar shall be compacted by striking with a hammer a steel pipe placed around the bolt or a hardwood rod. If a pipe is used, it shall be of such diameter that it can be shifted laterally to obtain compaction over the entire mortar surface.
More than one size of pipe may be required.
If a hardwood rod is used, it shall have a diameter such that the entire grout surface can be compacted.
Anchors using portland cement grout or dry-pack mortar may be placed in service in 7 days and 3 days, respectively, provided that the exposed surface has been protected from drying and that temperatures of the concrete have been maintained above 50 F.
Anchors using epoxy grout may be placed in service when final cure is achieved.
Accelerated curing according to manufacturer's instructions is permissible.
Unless otherwise called for, grouted anchors 5/8 inch or greater in diameter shall be tightened to that tightness attained with a few impacts of an impact wrench or the full effort of a man with an ordinary spud wrench.
Smaller anchors shall be tightened 1/4 turn after the nut, washer, attachment, and concrete have come into intimate contact.
3.5 Location (Anchor centerline) 3.5.1 General Unless otherwise called for, the restrictions of sections 3.5.2 and 3.5.3 shall be applied to the location of anchors.
(These requirements ar'e given in the Design Standard and should be used by the CONST project for anchors installed for construction purposes.)
3-4
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 3.0 INSTALLATION (Continued) 3.5.2 Ex ansion Anchors 6-32 Expansion shell anchors shall not be located closer to a free concrete edge than 6 nominal bolt diameters, or 10 bolt diameters if the anchor is loaded in shear toward the edge.
Hedge bolt anchors shall not be located closer to a free concrete edge than 10 nominal bolt diameters regardless of loading.
Minimum spacing between expansion shell anchors and wedge bolt anchors shall be as given in the following table:
Minimum S acin (in.)
Size (in.)
1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
l-l/4 SPD and SSD 2"1/2 3"1/2 4
5 5-1/2 6-1/2 7
WB 3
4 5
7 8-1/2 9"1/2 10-1/2 3.5.3 Grouted Anchors Grouted anchors shall not be located closer to a free concrete edge than 6 nominal bolt diameters, or 1.25 times the minimum embedment if the anchor is loaded in shear toward the edge.
Grouted anchors shall not be located closer than 16 nominal bolt diameters from an adjacent bolt.
Grouted anchors used as replacements for expansion anchors are not required to meet these location requirements.
3.6 E uivalent Anchors Unless otherwise called for, anchor substitution may be made if the load capacity of the substitute anchor equals or exceeds the load capacity of the called for anchor in both tension loading alone and shear loading alone.
The following working load capacities in tension alone and shear alone as provided by the Design Standard are to be used to determine acceptable substitute anchors.
3-5 TVA 10535 (EN DES-5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOI'T ANCHORS SET N
3.0 INSTALLATION (Continued) 3.6 Fquivalent Anchors (Continued)
Allowable Workin Loads (Ki s)
Anchor
~Te
~Ioadin Size 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1
1-1/4 SSD Tension 0.54 0.78 1.14 1.74 2.34 3.30 3.96 Shear 0.30 0.50 0.80 1.40 2.25 3.30 4.50 SPD Tension 0.45 0.65 0.95 1.45 1.95 2.75 3.30 Shear 0.30 0.50 0.80 1.40 2.25 3.30 4.50 Tension 0.60 Shear 0.50 Grouted Tension 0.58 0.94 (A 307 Shear 0.39 0.63 or A 36) 0.90 2.10 2.75 4.20 6.30 8.20 1.20 2.00 3.00 4.15 6.70 9.75 1.42 2.58 4.10 6.06 8.39 11.00 17.6 0.95 1.72 2.73 4.04 5.60 7.30 11.70 (Note:
The above table shall not be used for design.
Design shall be in accordance with the Design Standard.)
3.7 Reinforcin Steel Unless otherwise called for, no reinforcing steel shall be cut to install anchors without specific approval of the design representative in section 1.3.
3-6
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 4.0 TESTS G-2 Testing is required on expansion anchors designated as
- SSD, SPD, or WB for all equipment in nuclear plant category I structures.
Testing is not required on anchors designated EA, expansion anchors supporting a 1-hole pipe strap for an individual conduit less than 4 inches in
- diameter, or other anchors where EN DES documents state that testing is not required.
Tests shall be made as soon after installation of a lot as is practicable.
Anchors which fail to meet the requirements shall be replaced in accordance with section 5.0.
4.1 Selection Anchors to be tested shall be randomly selected within a lot after installation of the lot. If there are anchors of more than one bolt size in a lot, the size difference shall be ignored unless some anchors are twice the size of the smallest anchors.
In this case, approximately one-third of the tests shall be on the smaller size(s) and two-thirds.shall be on the larger size(s).
Number of Anchors in Lot Minimum Number to be Tested Less than 5 5 to 15 16 to 60 More than 60 1
2 3
5 percent 4.2 E
ansion Shell Anchors (SPD and SSD) 4.2.1
~Eui ment A calibrated center-hole hydraulic jack equipped with a gage whose least division represents no more than a 100-pound load on the anchor shall be used to load the anchors.
The load shall be transferred from the jack to the anchor with a high-strength threaded rod with a minimum yield strength of 50,000 psi.
The reaction from the jack shall be delivered to the concrete surface through a device which bears no closer than S inches from the anchor centerline and which is adjustable to ensure that the anchor is loaded axially.
The load-pressure relationship for the jack shall be verified before initial use and at 1-year intervals thereafter.
The gages used with the jack shall be calibrated every 2 months or every 100 anchor tests, whichever occurs first; but calibration is not required more frequently than every 2 weeks during continuing anchor installations.
The jack and/or gage shall be recalibrated any time there is a question as to jack operation or gage accuracy.
4-1 TVA 10535 (EN DES-5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOIT ANCHORS SET IN HARDENED CONCRETE G-2 4.0 TESTS (Continued) 4.2.2 Procedure The high-strength threaded rod shall be inserted in the anchor or coupled to the bolt of the anchor.
The hydraulic jack and bearing device shall be centered over the threaded rod and adjusted until the threaded rod is axially concentric with the center hole of the jack.
A nut and bearing plate shall be put on the threaded rod and snugged against the ram of the jack.
Load shall be applied without shock and as uniformly as practicable to the proof load as follows:
Bolt size (in.)
1/4 5/16 3/8 1/2 5/8 3/4 7/8 Proof load (lbs.)
900 1700 2200 4000 5400 7600 8300 If an anchor slips, it shall be reset and retested or it shall be replaced and the new anchor tested (see section 5.0). If an anchor slips in being retested, it shall be replaced.
If an anchor slips, an adjacent anchor shall also be tested.
{The loads are not intended for concrete strengths less than 3000 psi, or for concrete
- masonry, or for anchors set closer than 6 bolt diameters to an edge.
Failures at or below proof load should be by slipping of the anchor within the hole.)
4.3 Wed e Bolt Anchors (WB) 4.3.1 EqEui ment Calibrated torque wrenches with capacities approximately 25 percent greater than the installation torque of the largest bolt to be tightened with each wrench shall be used to verify that appropriate installation torque was applied to wedge bolt anchors.
Wrenches shall be calibrated every 6 months or any time there is a question as to wrench accuracy.
4.3.2 Procedure Torque shall be applied to the anchor without shock and increased as uniformly as possible to the torque determined in section 3.3. If the nut on an anchor is turned by this
- torque, two anchors in addition to the number required by section 4.1 shall be tested.
If the nut on any subsequent anchor turns, all anchors in the lot shall be retightened and a new test sample selected in accordance with section 4.1.
If the nut on any of these anchors turns when torqued, all anchors in the lot shall be tested.
Anchors on which the nut turns when torqued after retightening shall be replaced and the new anchor tested.
4-2
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE
- 5. 0 REPLACEMENT 5.1 General 5.1.1 Ex ansion Shell Anchor An expansion shell anchor which requires replacement at the same location shall be replaced by the next larger size expansion shell anchor or by a grouted anchor of the same or larger size.
A grouted replacement anchor does not require testing.
5.1.2 Wed e Bolt Anchors A wedge bolt anchor which requires replacement at the same location shall be replaced by a wedge bolt anchor of the same or larger size or a grouted anchor of the size required by section 3.7.
5.2 Removin Anchors 5.2.1 E
ansion Shell Anchor Expansion shell anchors which slip under test loading may be removed by the test equipment except that the hydraulic jack shall bear directly against the concrete around the anchor, or by an alternate method which prevents spalling of the concrete surface.
If the anchor is not to be replaced by another in the same location, in lieu of removing the anchor, the anchor shell may be dry packed or grouted full.
5.2.2 Wed e Bolt Anchors Wedge bolt anchors that have failed to meet torque, projection, or attachment thickness requirements may be removed by jacking from the hole with a center hole jack which bears directly against the concrete adjacent to the anchor or by an alternate method which prevents spalling of the concrete surface.
If the anchor is not to be replaced by another at the same location, the anchor may be cut off as close to the surface as possible, driven into the hole, and the hole dry packed or grouted full.
5-1 TVA 10535 (EN DES.5-77)
~
~
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED CONCRETE 6.0 RECORDS AND REPORTS 6.1 General G-32 Records shall be made of all anchor testing and replacements and kept in the plant records storage.
For a lot in which an anchor failed when tested, one copy of the complete report as specified in section 6.2 shall be transmitted to the appropriate EN DES Design Project Manager upon the completion of testing and corrective action on that lot.
For lots in which no anchors failed when tested, a memorandum shall be transmitted monthly while anchor installations are being made, listing the project
- feature, the test report number, and the lot identification on all such lots'eports shall include the project feature; the test report number; identification of the anchor lot; the type and brand of anchor used; the total number of each size anchor in the lot; the number of each size anchor tested; the location, size, and slip load of each expansion shell anchor which exhibited slip, with the corrective action taken; the location and size of wedge bolt anchors that failed to meet torque or projection requirements; 5
and information on jack or torque wrench calibration as called for in section 4.2 or 4.3.
The boundaries or identification of all anchor lots, the test report number for each anchor lot, and the identification of the specific anchors tested in each lot shall be recorded as called for in section 1.2.
Test information shall be transmitted to EN DES as required in section 6.1.
Required drawings shall not be general equipment layouts, but shall show specific anchor locations, except if anchors are shown only on drawings of individual equipment, such drawings or portions of them may be
'used, but they shall be referenced to their layout drawing and that drawing shall be marked to show the boundaries of anchor lots.
6-1 TVA 10535 (EN DES.5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET IN HARDENED N
AppendixA QUALIFICATION TESTS FOR EXPANSION SHELL ANCHORS A.l SCOPE This method of test shall be used to determine the ultimate tensile capacity of expansion shell anchors (type SSD and SPD).
Tests shall be made on each brand, type, and size of anchor that is to be used.
A.2 APPARATUS The apparatus shall consist of that required by section 4.2.1.
A.3 PROCEDURE Place a minimum 8-inch-thick concrete slab with 3/4>>inch-maximum size aggregate in accordance with 6-2.
The average compressive strength of two field-cured standard cylinders shall be between 3000 and 4000 psi at the time of anchor testing.
Install three anchors of each size in accordance with section 3.2.
The minimum edge distance shall be 6 nominal bolt diameters and the minimum anchor spacing shall be 12 nominal bolt diameters.
The drill bit diameters shall be those required by section 2.3.
Thread the high-strength rod into the anchor.
Center the jack and bearing device over the high-strength rod and adjust the location until the rod is axially concentric with the center hole of the jack. Place the bearing plate on top of the jack and snug it down against the ram of the jack with the nut.
Load the anchor uniformly and without shock until the anchor fails.
A.4 REPORT The report shall include the anchor brand, type, and size, the ultimate tensile capacity of each anchor, the average ultimate tensile capacity of each 3-anchor set, the mode of failure of each anchor, and the concrete class and compressive strength at the time of anchor testing.
A-l TVA 10535 (EN DES.5-77)
GENERAL CONSTRUCTION SPECIFICATION FOR BOLT ANCHORS SET I AppendixB QUALIFICATION TESTS FOR WEDGE BOLT ANCHORS B.l SCOPE This method of test shall be used to determine the ultimate tensile capacity of wedge bolt anchors (type WB), to determine if the installation torque given in section 3.3 will result in the required
- preload, and to determine the required installation torque if the torque given in section 3.3 does not result in the required preload.
Tests shall be made on each branch,
- type, and size of anchor that, is to be used.
B.2 APPARATUS 1.
Calibrated center-hole hydraulic jack equipped with a gage whose least division represents no more than a 100-pound load.
2.
High-strength coupling nut, a high-strength threaded rod (rod size and yield strength shall result in a yielding force in the rod at least 20 percent greater than the required ultimate tensile capacity of the anchor),
and a bearing plate and nut for attachment to the jack.
3.
Bearing device for transferring the jack reaction to the concrete surface at least 15 inches from the anchor centerline and which is adjustable to ensure that the anchor is loaded axially.
4.
Calibrated torque wrench.
B.3 PROCEDURE Place a minimum 15-inch-thick concrete slab with 3/4-inch-maximum size aggregate in accordance with G-2.
The average compressive strength of two field<<cured standard cylinders shall be between 3000 and 4000 psi at the time of anchor testing.
Install three regular length wedge bolt anchors of each size in accordance with section 3.3.
The minimum edge distance shall be 10 nominal bolt diameters and the minimum anchor spacing shall be 12 nominal bolt diameters.
The drill bit diameters shall be those required by section 2.3 for qualification tests. Install each anchor through a steel plate or plates which have a total thickness equal to the maximum attachment thickness given in section 3.3.
The bearing plates shall be small enough to permit the bearing device to bear on the concrete.
Before tightening and without changing the bolt projection, remove the plate and install a thinner
GENERAL CONSTRUCTION SPECIFICATION FOR B
C B.3 PROCEDURE (Continued) plate, or if multiple plates were used, remove one or more of the
- plates, so that sufficient threads are available for tightening and coupling to the loading device.
Tighten the anchor to the torque given in section 3.3.
Couple the high-strength rod to the anchor.
Center the jack and bearing device over the high"strength rod and adjust the location until the rod is axially concentric with the center hole of the jack.
Place the bearing plate on top of the jack and snug it down against the ram of the jack with the nut.
Load the anchor uniformly and without shock until the washer can be moved with the fingers (lift-off). If the load at lift-offis greater than 1.5 times the working load tension of section 3.7, the installation torques given in section 3.3 are acceptable.
If the lift-offload is less than 1.5 times the working load, loosen the nut and then retighten to a torque approximately 10 to 20 percent greater than previously used.
Reload to lift-off. Continue lift-offtests until a torque which produces the required tension is achieved.
The average torque for the three anchors of each size tested shall be the installation torque.
After completion of lift-offtests, load the anchor until the anchor fails.
B.4 REPORT The report shall include the anchor brand and size, all data relating to determination of installation torques, the ultimate tensile capacity for each anchor, the average ultimate tensile capacity of each 3-anchor set, the mode of failure of each anchor, and the concrete class and compressive strength at the time of anchor testing.
B>>2
ATTACHMENT B
AFD HEAD raalLLapr Aaaoaaaarr Mf-IIIIllilngan&OIS
~ Drillsitsown hole, eliminating costly carbide bits.
~ Resists shock and vibration.
~ installs fast, easily and economically I/Iiththe 747 Roto Stop Hammer.
aa
~or.r >y
-A-j a
The REDHEAD Self-DrillingAnchor provides its own case-hardened steel drillfor every hole, eliminating the need for expensive and easily damaged carbide drills. Its unique design assures consistent holding capacity plus superior resistance to shock and vibration. It's the most dependable heavy duty anchor in the industry. Installation with the 747 Roto Stop Hammer creates one of the fastest, simplest and most economical "anchoring systems" in the world.
INSTALLATION PHYLL)PS Red Head'
~a
- ~
n aln
'1. faRILL HOLE-Remove anchor and clean out hole. Place eed plug In anchor.
E. EXPAND AMCMOR-Ralnxad anchor ln hola and expand unIII flush. Snap off cone.
- 3. BOLT-Secure obJect to complete Installation.
(o o) 0 h'4 ad POA 42 b
4 ad ~~4'r do a 4
o A,er,a~.
C' gal@
a d dru +
d5XS <
~ 4 I I'I I ga du 4 42 O+ag 4~d2 dg l/
I ~
x Snap oft
~ type For Instailation with electric or aif Ifnpact
, hammers.
Cat.
No.
~ S14
~ 516
~ 5.38
~ S-12
~ 5-58
~ 5-34
~ 5-78 Bolt Slee j}
]Ixr v
yr Oepth In Con-crete Igr
]pir
]lgr 31](r thread Oepth y>>
/+a ~
](E" s](r 9'"
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] $]
nr Outs de Olam-eter Jf >>
']fr"
]fr
)](r year
]r]I/r Pullout 3670 4060 5670 8500 11,700 16,200
]7550 Shear 1335 2030 3370 6720
]1.900 16,200
]8,450
'Load Capacity In 3500 Pdh.l. Concrete, LBS.
PHJ L LIPS Red Head'
~
Flush type For hand Instal-lation with FH-300 series flush/hofdera.
{See P.16)
Cat.
Ne.
~ f 4
~ f.16
~ F48
~ F12
~ F58
~ F.34 Bolt Size y>>
]fr jgryrI" 7p r Oeplb
]bread In Con.
Oepth crete per
]14>>
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]rhxr 2 /)
xa 3>>
Outs dc Blam.
ster Jf >>
rg' pa r
']('1
'oad Copse ty In 3500 PS.I. Concrete,
]BS.
Pullout 3670 4060 5670 8500 11,700 16.200 Shear 1335 2030 3370 6720 1],900 16,200
'avsoe orh lruserohndrnt Tvatlhg Lsborhrory testa. Report hvallabr ~ on P. 21.
Tests coroeucted In atone Eggrvgdte concrete.
FOr mvnuIEClulerh reeOmrhoduled
~ EIV Eaarhlrhg lOada uSE 2SV Ot EbOW IOEd Valuea.
sl ~ EI ~ or ~ Ecvvds v.s. oouarnprvrhr o.sA spvcllhcalion No. FF<42$ ~ orguro III,Typo 1. IOEIEe el so/sTI For lhEIEREIIoh ldh ~Iruclurvl Ilghl EEEIght copocrvl ~ v EE rooc or the vborv toad rEIMEE.
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4
D OB 2 R N E Bc EL GE N S ON, Consulting Enginccrs IISRE WEDDINOTON STR EET NORTH HOLLYWOOD. CALIFORNIA
~
TRIANGLE 7iSOSI File No. 626 September 25, 1962 Xhillips Drill Com pany.
Michigan City, Indiana REPORT PULLOUT CAPACITIES OF PHILLIPS RED HEAD CONCRETE ANCHORS AS AFFECTED BY SPACING In compliance with the request of the client, Doberne 4 Elgenson conducted a series of tests to develop the information used in this report.
'Ihe test facilities of the Smith-Emery Company, an independent testing laboratory, were used, The purpose of these tests was to determine the load holding characteristics of Phillips anchors under various spacing arrangements.
I Results 1, When the spacing between adjacent anchors reaches a distance equal to several times the anchor diameter, there is no loss in capacity.
The following table shows the minimum center-to-center spacing that could be used with each anchor without causing a loss in individual
- capacity, Anchor Bolt Size Minimum Spacing for 100% capacity 1/4" 5/16N 3 II 3 1/4ll 4 II 5ll 3/8ll 1 /2tl 5/8 II 6 II 3/4" 7(8ll 81l
- 2. When the center-to-center
- spacing, as shown in the above table is
- reduced, the capacity of the individual anchor decreases.
The following table shows center-to-center spacing corresponding to a 20% reduction in individual anchor capacity.
Anchor Bolt Size 1/4" 5/16" 3/8" 1/2 II
/8ll 3/4 ll 7(8" Minimum Spacing 1-1/2" for 80% Capacity 1-5/8" 2tl 2-1/2" 3 ll 3 1/2 II 4 II I
I I
F330P I
Dimensions of blocks used for tests were 8" x 8N x 16N with an average compressive strength of 2650 psi.
Res pectfully submitted, 4
bk Nor ris Doberne, C. E.,
S. E.
ATTACHMENT C,
PNILVI~
ANDNOAO IXX Phillips DrillCompany Michigan City, indiana 46360 SPACING, EDGE AND END DlSTANCE RECOMMEMDATlONS*
SELF-DRILLtNG AND NON-DRILLINGANCHORS Anchor Size, Inches Spacing Distance, Inches Edge And End Distances, Inches Load Parallel Or Away From Edge Load Toward Edge 3Va 3V4 2s/4 3 /4 5Va 5Vi STUD, WEDGE AND SLEEVE Anchor Size, Inches Spacing Distance, Inches 1a/4 2Vz 2't/a s/a 4s/a 5V4 SV4 Edge And End Distances, Inches Load Parallel Or Away From Edge Load Toward Edge
'I Va 1s/4 2
2s/a 2t/a 274 3Vz 3'/a 4t/a 4Vz 5Vz 6V4 MULTI-SET Anchor Size, Inches Spacing Distance, Inches Edge And End Distances, Inches Load Parallel Or Away From Edge Load Toward Edge 2a/a 274 SV4 5%
'Distances for 100% of "Safe Working Load". To determine the "Safe Workfng Load" consult general catalog.
Q fs.rs) Form <<r$2lr
TENNESSEE VALLE,Y AUTHORITY DIVISION 5F ENC)NRERING OESIGN f70
~Y ALL PROJECTS GENERAL COI'vSTR UCTION SPECIFICATION NO. G-32 FOR 80LT ANCHORS SET IN HARDENED CONCRETE
- r~-r ~~"rp ) f ~T > PQ!
SepI'eeber 1972 U jQ~Q J','QPPT SPONSOR ENGINEER SUBMITTED
. E. SullocZ
- 0. H. Reine SPECIFICATIONS SECTIO~
. L. Duncan APPROVED R EVIEWED
+ ~e.kL C. H. Glaze RECOMHENDED F-P.
/<<4 g'P "
APPROVED of Construction Di ctor of Engineering Design CI C
~
~ ~
GENERAL CONSTRUCTION SPECIFICATION NO G-32 FOR BOLT ANCHORS SET IN HARDENED CONCRETE Section COSTSS1S GENERAL 1.1 Scope 1.2 Drawings 1.3 The Engineer 1.4 Reference Specifications 1.5 Definitions 2.
KKTERIALS 2.1 Expansion Anchors 2.2 Grouted Anchors 2 3 Bolts 2.4 Portland Cement Grout 2.5 Epoxy Grout 3.
XtSTALLATION 3.1 Expansion Anchors 3.2 Grouted Anchors 3.3 Location 3.4 Embedments 4.
res 4.1 Selection 4.2 Equipment 4.3 Procedure 5 ~
REPIACEK2iT 5.1 General 5.2 Removing Slipped Anchors 6 ~
RECORDS AND REPORTS 6.1 General 6.2 Report Content
GEHKQL CONSTRUCTION SPECIFICATION NO. G-32 BOLT ANCHORS SET IN HARDENED CONCRETE 1.2 1.3 I
GfffEEAL gcope.
Zt is the purpose of this specif'ication to prescribe materials and methods for setting threaded, anchoring devices for equipment and fixtures into concrete which has previously hardened.
The work includes installation procedures and testing of selected anchors.
Testing is required on expansion anchors f'r all equipment in nuclear plant Category X structures.
Draufn s.
Anchors for all Category I equipment fn nuclear plant, structures shall be provided according to drawing prep"ared by the Division of'ngineering Design.
Anchors f'r other equipment shall be provided according to drawings prepared by the Division o i
D or if so directed according to manufacturer,'s p
Desi n.
recuirements as approved by the Division of Engineering es gn.
Changes sha11 be made only wraith the approval of the Engineer.
The projec o Ance s t f hall prepare drawings showing the location of testi and test infonmtion on each lot of'nchors which require es ng.
The En ineer.
The Engineer as used in this specification shall mean t
tion.
For design considerations, these shall be the e
r riate Desi n Division of'ngineering 3)esign acting through the approp g
Branch Chief.
For construction, in general, these sha23. be joint the appropr a e esxgn i t D
n Branch Chief and the project Construction Engineer.
Any e
a~a Any d vi
'on from this specification must be agreed to oin
-by hem.
3.,4 Reference S ecifications.
The latest revisions of the fol1cnring specifications shsi1 apply where referred to in this specification.
American Socie y for Testing and Materials:
A 36
- Standard Specification for Structural Steel A 307
- Low-Carbon Steel Externally and Internally Threaded Standard Fasteners C 144
- Standard Specification for Aggregate for Masonry Mortar D 63S
- Standard Method of Testing for Tensile Properties of Plastics
Corps of Engineers, U.S. Army:
CRD-C590
- Federal Specification Grout, Adhesive, Epoxy Resin, Flexible, Filled.
.Va13.ey Authority:
General Construction Specification No. G-2 for Plain and Reinforced Concrete le5 Definitions.
Wherever the ~ords defined below appear in this specificationp they shall have the meanings here given.
Anchor.
d threaded device for'ttaching equipment and fix'tunes to existing hardened concrete.
An expansion anchor expands iatersldX a portion of its length against the sides of a drilled hole to transfer load.
A grouted anchor is a headed bolt, or threaded rod, with an end. nut, in a drilled hole the remainder of which is.filled with grout to transfer load..
Lot.
This applies o~ to nuclear giant Category l structures.
A lot of anchors shall consist of (a) the anchors for a single piece of'quipment having three or more anchors, or (b) all the anchors on a Moor, wall, or ceiling surface which has convenient ind1cated boundaries, or (c) a long line of anchors on a floor, wall, or ceiling for a continuous structure such as a cable tray.
Anchors installed in separate construction operations shall be considered, to be in separate lots.
Slim.
During testing an anchor sha11 be considered to have exhibited slip if the gage on the loading device indicates a dropoff or lack or advancement of load while the anchor is being strained.
1-2
E ansion Anchors.
Unless otherwise called. for on the drawings, expansion anchors shaLl be used on1y with bolts smaller than 1-inch diameter. 'or al1 equipment in nuclear plant Category I structures, and for other eouipment unless otherwise called for on the drawings~
such anchors shaU. be Phillips Red Head, Self-DriU.ing Anchors, Phillips DrillConpany, Incorporated, Michigan City, Indiana~ or equal.
2.2 Grouted. Anchors.
Unless o herwise called for on the drawings, grouted
'nchors shall be used for all anchors requiring bolts 3.-inch diameter or larger, and. where replacement of slipped. expansion anchors with other expansion anchors is impractical.
2-3 2.4 Bolts.
Unless otherwise called for on the drawings, all bolts sma13.er than 1-inch diameter shall conform to ASTM A 307, Grade A, and all bolts of 1-inch diameter or larger shall be made of rods which conform to ASTH A 36, with nuts conforming to ASTN A 307, Grade A.
Rods shall have coarse threads on both ends with anut on the embeMed encl which is tack welded in place.
Portland Cement Grout. Allmaterial shaill conform to the requirements of General Construction Specification Ho. G-2.
Cement may be Type I, or Type II.
The ratio by weight of water to cement shall not exceed.
0.5.
A gelling agent or pu~ing aid~ or a grouting aid. incorporating a gelling agent shall be used in sufficient quantity to prevent bleeding.
Sand conforming to AS' 144, except that no more than 10 percen shall pass the le. 100 sieve, shall be added in as great a quantity as willprovide adequate flowability. Anchors using such grout r~ be placed, in service in 7 days provided that the exposed surface has been protected from drying and that temperatures of the concrete have been maintained above 50 F.
2.5h:..
6 component ra io one to one by volume.
One component shall be 100 percen reactive resin with an epoxide equivalent of 175 to 195.
The o her component shall contain polyethylene amines together with necessary diluting agents and fillers.
The mixed material shall have a minimum nonvolatile content of 98 percent, an initial viscosity of 1800 to 2200 centipoise at 75 F, a minimum pot life of 25 minutes at 75 F~
and. the ability to cure at temperature down to 35 F.
After 7 days cure at 75 F, tne tensile strength by ASTM D 638 shall be a minimum of 5500 psi, and the compressive shear streng h by CRD-C590, except that the 2-inch cubes used in the test shall be steel shall be a minimum of 2000 psi.
The manufacturer shall certify that the material supplied meets the requirements and shall furnish ccraplete ins ructions for its use.
Such instructions shall be followed in de'ail.
Sandblast sand or other oven-dry fine aggregate 2-1
with none passing the No. 100 sieve shall be aMed. 9n as great a quantity as willprovide ad,equate f1owability and, wetting of the sides of the hole.
Anchors may be placed in service when fina3. cure is achieved..
Accelerated. curing according to manufacturer's instructions is permis'sible.
2~2
3.
INSTALLATION ZEI manufacturer's instructions.
Special care shall be taken to clean dust and. debris from holes before expanding the anchors.
3.2 Grouted. Anchors.
Holes shaLL be drilled ten nomina3. bo3t diameters in depth and. with a cLiameter twice the nomina1 bo3.t diameter.
Ho1es shall be cax efully cleaned, of a33. dust and. cLebris.
Grout comp3ying with either section 2.4 or section 2.5 may be used. unless otherwise indicated on the drawings.
Mhere grout willnot flow from the hole, the ho3.e sha13. be fi33.ed approximately ha3.f fu11 of grout and the bolt inserted. by twisting and working in and out to ensure elimination of all voicLs.
Any remaining hole shall then be fi11ed with grout, the bolt shall be fixed in position and the grout cured..
Mhere grout will f3.ow from the hol, the hole and. anchor shall. be fitted with a cover plate of wood. or other materia1 through which the grout can be pressure injected.
A snuQ3. pipe vent sha13. 'be placed to th highest elevation in the ho3.e and. grout injected through a port in the cover plate until it flows from the vent.
Both the port and the vent shall then be pos5.tive3y closecL off.
The cove'r plate shall be coated with a bond, preventing material on the grout side and sha13. be xemoved after the grout has cuxed.
3.3 ication.
Unless otherwise indicated on drawings~ no anchor shal3.
be 3.ocated. closer than five bolt diameters to a free concrete edge or ten bolt diameters to an adjacent bolt.
3.4 Enhedments.
Required. embedments of all anchors shaLL be fxom the f'ace of structural concrete and shall not include topping or cladding.
Mhere self'-driU.ing anchors axe used, topping or cladding shall be predrillecL to admit the drill chuck to the proper depth.
3-1
4.1 4.2 Testing is required on expansion anchors for all equipment in nuclear plant Category I structures.
Tests sha13. be made s.s soon after installation of a lot as is practicable.
Selection.
Anchors to be tested.
shs13. be random'elected, within a lot after installation of'he lot. If.there are anchors of more than one bolt size in a lot,"the size difference shall be ignored unless some anchors are twice the size of the smallest anchors.
In this case, approximately one-third, of the tests sha31 be on the smaller size(s) and two-thirds shall be on the larger size(s).
If a lot contains less than five anchors, test at least one anchor.
If' lot contains five to fifteen anchors, test at least two anchors.
If a lot contains sixteen to sixty anchors, test at least three anchors and if a lot contains more than sixty anchors~ test at least 5 percent.
E>>>>uEXment,.
A callbratea center-hole hrdraultc
$ach e>>tutppea trlth a gage whose least division represents no more than a 100-pound, load.
on the anchor shal3. be used to load 'the anchors.
The load, shall be transferred.
from the pack to the anchor with a high-strength threaded rod with a minimum yield, strength of 50,000 psi.
The reaction from the pack shall be delivered to the concrete surface through a device which bears no closer than 8 inches radially from the anchor center-line and which is adjustable o ensure that the anchor is loaded.
axi~.
The calibration of the pack shall be checked every 2 months or every one hundred, anchor tests, whichever occurs first. If any question as to the pack's accuracy occurs, the pack shall be recalibratede 4.3 Procedure.
The high-strength threaded. rod shall be inserted in the anchor or coupled to the bolt of the anchor.
The hydraulic pack and bearing device shall be centered over the threaded rod and a(/usted until the threaded rod is axially concentric with the center hole of the Jack.
A nut and bearing plate shall be put on the threaded rod and snugged against the ram of the pack.
Zoad shall be applied without shock and as uniform3y as practicable to the proof load as follows:
Bolt size (in. )
1/4 5/16 3/8 3./2 5/8 3/4 7/8 Proof load (lb) 900 1700 2200 4000 5400 7600 8300 If an anchor slips, it shall be reset and retested or it shall be replaced and. the new anchor tested (see section 5). If an anchor slips in being retestcd, it shall be replaced. If an anchor slips, an ad)acent anchor shall also be tested.
(The proof loads listed are approximately either Oe9 of the minimum yield loads of the bolts,
or are 0.5 of the pu33.out capacity of the concrete surrounCing the
- anchor, based.
on concrete strength of'000 psi but used. a1so with other strengths.
Any failure which occurs at the proof losci or below should. be by slow frictional slippage of the anchor within the hole.)
4-2
5 REPIACEHENT
\\
5.1 General.
An anchor which requires xeplacement shal3. be replaced by 1
i expansion anchor or hy a arocteK anchor of'he same or larger bolt size as the anchor replaced..
A grouted. replace--
ment anchor willnot require testing.
5e2 Remov1 S3.i ed Anchors.
Anchoxs which slip under test loading sha11 be xemoved by the test equipment except that the hydraulic pack shall bear directly against the concrete around the anchor, or by an a1ternate method which prevents spelling of the concrete surface.
5-1
~
~
1 6
RECORDS KG) REPORTS 6.1 General.
Records shall be kept of all anchox teWing and replacements..
f rte eheht he trenemttteg to the Ctvl1 Design Breech as 'the testing in each lot is completed~
or once monthly if installation and. testing of several sxQacent lots is continuing.
6.2 Re ort Content.
Reports shall include the boundaries of each anchor h total number of each size anchor in the lot, the number of each size anchor tested,,
and. the location of each anchor whicch exhibited slip with the corrective action tegmen.
All the information shall be recorded on the project office drawings called for in section 1.2, snd. prints of the drawings transmitted as required in section 6.1.
Xf successive reports cover anchors on the sane drawings, tests and, test results since the previous transmittal sha13. be iden~ified.
Tne drawings sha13. fin~ include aU. test results.
ATTACHMENT D
BRANS FERRY FIELD TRIP - APRIL 26, 1979 CEB:
Jim Kincaid and Ray Funk Browns Ferry contact:
Randy Summers Test data is only available after August 1973.
Before that time the anchors were installed according to the instructions that came with the self-drill anchors.
The quantity of tests are relatively limited when compared to the amount of testing required in the later plants.
Out of aU. the testing there were only seven failed anchors; however, six of these failures were in the same lot.
Records of this test show that the anchors were 5/8-inch-diameter but the testing procedure called for 7/8-inch anchors.
It looks as if six of these anchors may have been tested for the proof load of 7/8-inch anchors and. failed before it was discovered that these were 5/8-inch anchors.
It is possible that the testing personnel measured.
the sheU.
and, mistook that dim nsion for the anchor size.
Randy Summers is having the test data reproduced and wiH. mail the data to us. It should arrive by Monday.
The inspection covered as much of the plant as possible without going to the areas that would require suiting up.
The inspection did extend into the area outside the torus.
The radiation level was 30 to 100 mil3.irems around the torus so that this was a "no linger area."
The general type of use of self-drills were not the type that is of ma)or.
concern in the NRC 79-02 bulletin. l was not able to find any instance where multiple rows of anchors were loaded through flexible plates.
The use of tube section cantilever system welded to unstiffened plates was noticable by their absence.
Xn three instances anchorage failures were observed.
Xn each case it was obvious that the support system was not operating the way it was designed.
These were very stiff support systems for which the direction or magnitude of load producing failure was not anticipated. in design.
The best way to check anchorages is by inspection of the gap and. protrusion of the anchor shell.
The best time to catch this is inspection during hot testing or on outages by people who know what the anchors should be doing.
When some of these pipes lock up and move in an unexpected direction they can overpower almost any anchor.
When these are found it needs attention to get the systems to where they are compatible whether it means readgusting the strap, relocating the support, or changing the anchorage.
l
It would not be a desirable axea for testing since it would require that the work crews would have to work near the ceiling where the radioactivity was at a maximum.
This might cause the crew to get the maximum dose in the short time they would be in there.
In general the support systems tended to be the type of'lexible loading that is best suited f'r self-dry. anchors.
Cable trays were supported from a channel that was anchored. to the ceiling.
Trapeze rod hangers then were connected to the channel f'r tray support.
When lateral support was required, wide flange sections were attached to the wall and ceiling in an L shape.
Large piping appeared to generally be supported on embedded plates which had been installed for that purpose. It was always the smaller piping systems that were located after the concrete had been poured, that required the use of post installed anchors.
The ma)ority of these systems were primarily tension type devices that work best with the self-drill anchors.
Typical installations were single xod. hangers going to a single anchor for light loads and a plate with four anchors where heavier loading was required.
These plate systems would tend to have the load limited by the xod. capacity instead of'he anchor capaci4y.
These would not be a ~or problem to test since the xod. and. plate could be removed. to test the anchors.
Prior to G-32, there was no difference in installation and. testing between class 1 end non-category systems so that testing of non-safety xelated systems could be expected. to represent the general level of workmanship that was used at the time without Jeopardizing a safety system.
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ENCLOSURE 2 TENNESSEE VALLEYAUTHORITY DIRFCT RADIATION LEVELS AROUND BROWNS FERRY NUCLEAR PLANT - BACKGROUND DATA This Report Contains Preliminary Information Subject to Change or Revision and Is Intended for Use Within TVAOnly
- WNV48IONOF ENVIRONMENTALPLANNING
DIRECT RADIATION LEVELS AROUND BROWNS FERRY NUCLEAR PLANT - BACKGROUND DATA By PHILLIP H. JENKINS AND RICHARD L.
DOTY TENNESSEE VALLEY AUTHORITY MUSCLE SHOALS, ALABAMA FEBRUARY 197,7
OVERVIEW In 1974, a study was conducted by various agencies of the federal govern-ment to develop a research program dealing with the human health and environmental effects of energy use.
This program was developed by.,
utilizing lists of health and environmental problems associated with each of eight energy-generating technologies.
Research
'objectives and prospects responsive to the research needs of each technology then were developed.
One of the technologies studied was energy generation by nuclear power.
Radiation exposure desigri objectives applicable to the nuclear power industry are established at levels believed to be as low as reasonably achievable consistent with current technology and societal objectives.
Approval for the construction and operation of nuclear power',plants is dependent on the assurance of safe operation in compliance with these design objectives.
Because this assurance is demonstrated by analytical
- methods, the validity of the models and the accuracy of the assumptions is of utmost importance for the timely and economical development of nuclear power..
Current dose models are based on assumptions which are believed by utility and regulatory personnel to be conservative; however, revision
. of these dose models may not be )ustified without supporting data.
Although limited, short-term studies have been conducted around operating
~
'uclear
~~ts to facilitate comparisons of actual and predicted
- values, these
-"pri objects have not provided the necessary data for compre-hensive verific4e9'on of the methodology of analytical do'simetry; Therefore, research ~ds were identified within the nuclear technology regarding
verification or revision of dose models.
High priority was given to the collection~+information and the development of programs pertinent to those needs, e~s'pecially those needs regarding the environmental transport of radionuclides.
1
'VA proposed a program of evaluation of dose models used for the assess-ment of the radiological impact from an operating nuclear power plant.
This program included collection of experimental data around a power plant and the evaluation and revision of existing atmospheric dispersion and dosimetry models.
TVA was noted to be uniquely qualified to develop improved analytical modeling capabilities, because of its extensive involvement with nuclear power plant operations and expertise in radiological monitoring and modeling technology.
The required information-providing organizations would all-be available within TVA, which would reduce the potential for communications problems in an arrangement'f plant operator and outside contractor.
- Further, implementation of the p'roposed program into TVA'8 existing assessment operations could be accomplished at minimal cost compared to establishment of a separate assessment
- program, because of the availability of support facilities, equipment, and personnel.
Therefore, in response to the proposal, TVA was funded to initiate studies related to the validation of dose models.
Work is being performed under the administration of TVA's Radiological Hygiene Branch in the Division of Environmental Planning.
This document is the first report to be issued by the staff as a result of the funding.
r
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CONTENTS
~Pa e
Overview List of Tables Acknowledgments Ui Sections Introduction Hateria ls and He thod s Experimental Phase Discussion, Summary and Conclusions References 14 35 37
TABLES No.
~Pa e
1 Summary of Data Direct Radiation Levels Browns Ferry Nuclear Plant 2
Comparisons Between Data Collected During the Day and During the Night 17 3
Comparison Among Zones 4
Locations Grouped by Exposure Rate 5
Comparison Among Instruments of Mean Fxposure Rates 6
Comparison Between Integral and Rate Methods Simultaneous Measurements 20 21
'23 26 7
Comparison of Integral and Rate Measurements By
'Instrument
.28 8
Results of Analyses on Background Data Taken.According to the Plume Detection Design 33
ACKNOWLEDGEMENTS This report is submitted in partial fulfillment of interagency agreement EPA-IAG-D6-E721, subagreement number 5, with funding under the administra-tion of the 'Fnvironmental Protection Agency (EPA).
The authors wish to thank James A. Oppold, Frnest A. Belvin, and Eric W. Bretthauer for their efforts in the management of this project.
Appreciation is also extended to William W. Wilkie, Walter S. Liggett, J. Herschel Davis,. James L. Pierce, Richard D. Smith, Brenda J. Williams, and Sadie B. Holmon.
INTRODUCTION This report presents the results of initial measurements of direct radiation levels around a nuclear power plant. 'hese data and data collected at later times will be used in revising computer codes used in calculating doses to individuals located near nuclear power plant sites.
Both a computer code which estimates doses resulting from exposure by submersion in the gaseous effluent plume from the plant and a code which estimates doses to individuals off-site resulting
'rom exposure to radioactive materials confined within the plant are expected to be revised.
Additional data and the revised codes will be the sub)ect of future reports.
Revision of these codes will lead to improved assessment of the impact of nuclear facility operation.'ata collected through June 1976 are presented in this report.
The purpose for this data collection was threefold:
(1) to obtain dat'a in the vicinity of a nuclear power plant which was not operating.
These data could be, considered to be background, control, or nonoperational data; (2)
To evaluate the performanc'e of instruments to be used in the collection of additional data; and (3)
To evaluate methods which might I
I I
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be used to identify or quantify doses received from radiation exposure
'rom radioactive materials in the effluent plume.
Reviewers should be aware that major effort to date has been focused on developing and evaluating a framework for future study.
This report is not a final report-'-'en model refinement or facility assessment, but rather a repo
~Q~~~.
on accompli'sl>m'ents in the first year of a five-year study.
~r'
Three boiling water reactors make up the power-generating capacity of TVA's Browns~gerry Nuclear Plant (BFNP).
Each of the units is capable of producing l,152 megwatts (lN) of electricity, making the complex one of the largest nuclear power facilities in the world and an excel-lent statio'n" on which to base studies of the impact of nuclear facility operation.
A temporary shutdown of the facility, beginning in 1975, provided the opportunity to gather a unique set, of data; that is, data at a large facility where construction activities had been essentially completed but where all reactor units were nonoperational.
The data discussed in this report were obtained at BFNP during this period of facility shutdown, utilizing pressurized ionization chambers.
4 MATERIALS AND METHODS Five instruments capable of accurately measuring environmental levels of gamma radiation were purchased for 'this project.
These instruments are the Reuter-Stokes Environmental Radiation Monitors, Model RSS-111, Serial Nos. T-3512, T-3513, T-3514, T-3516, and T-3517.
A sixth instrument, Serial No. T-3590, was loaned to the project from within the Radiological Hygiene Branch for brief periods of use.
The RSS-ill utilizes a high-pressure ionization chamber for the detection of gamma rays.
The chamber is a 25.4-cm (10-in.) sphere of 3.05-mm (0.120-in.) stainless steel containing pure argon at a pressure of 2.5 x 10 Pa (25 atm).
Mien.gamma rays interact in the chamber, an elec-trical current, is produced.
This current is measured by an electrometer and is directly related to the gamma-ray exposure rate.
The instrument has a digital display consisting of light emitting diodes (LED's) from which the instantaneous exposure rate can be read directly
'n units of microroentgen per hour (yR/h) over 'the operating range of 1 to 500 3IR/h.
The exposure rate is also recorded at intervals of approxi-mately two seconds on a strip-chart recorder.
The. instrument contains an exposure integrator which measures the total exposure accumulated
~
I over a period of time.
The read-out device for the integrator is a six-digit mechanical register which is incremented 6nce for every micro-
~
roentgen of accumulated exposure.
The instrument can be operated using
,'t'ormal
~~gbjjig current (AC) power or a rechargable battery pack which can be used for',-up to-200 hours of continuous operation.
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Agg!A%av MATERIALS AND METHODS Five instruments capable of accurately measuring environmental levels of gamma radiation were purchased for this project.
These instruments are the Reuter-Stokes Environmental Radiation Monitors, Model RSS-ill, Serial Nos. T-3512, T-3513, T-3514, T-3516, and T-3517.
A sixth instrument, Serial No. T-3590, was loaned to the project from within the Radiological Hygiene Branch for brief periods of use.
The RSS-ill utilizes a high-pressure ionization chamber for the detection of gamma rays.
The chamber is a 25.4-cm (10-in.) sphere of 3.05-mm (0.120-in.) stainless steel containing pure argon at a pressure of 2.5 x 10 Pa (25 atm).
%%en gamma rays, interact in the chamber, an elec-trical. current is produced.
This current is measured by an electrometer and is directly related to the gamma-ray exposure rate.
The instrument has a digital display consisting of light emitting diodes (LED's) from which the instantaneous exposure rate can be read directly in units of microroentgen per hour (pR/h) over the operating range of 1 to 500 llR/h.
The exposure rate is also recorded at intervals of approxi- ',
I mately two seconds on a strip-chart recorder.
The instrument contains an exposure.integrator which measures the total exposure accumulated over a period of time.
The read-out device for the integrator is a six-digit mechanical register which is incremented once for every micro-roentgen of accumulated exposure.
The instrument can be operated us'ing
~ ', M'-:-,
normal'N+mgtejgg current (AC) power or a rechargable battery pack which can be used for,'.up to 200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> of continuous operation.
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Fach instrument was calibrated by the manufacturer before shipment.
The calibratioq~pof the instruments has been checked by project personnel
~r<i t <~
using a Ra-226'source.
- However, a rigorous recalibration procedure, has not yet been established.
When an environmental radiation measurement is made, the sensor
- head, which contains the ionization chamber and the electrometer, is placed
.on a tripod such that the center of the chamber is approximately one meter (3.3 feet) above the ground.
The control circuitry, read-out
- devices, and battery pack are in a separate control housing, which is electrically connected to the sensor head by a six-meter, (20-foot) cable and is placed at least three meters (10 feet) from the sensor head.
The details of the operating procedure for the instrument are contained in the manufacturer's instruction manual.
Because various read-out devices are included in. the instrument, several methods of determining the exposure rate are possible.
Two methods have been used in this project.
The first method is referred to as the "rate"
- method, because the exposure rate is read directly from the LED display.
The exposure rate value observed on the display fluctuates rapidly due to the random nature of radioactive decay.
Therefore, several exposure rate readings must be averaged to obtain a meaningful measurement using this method..
Furthermore, this must be done in a consistent manner in order to make valid comparisons among measurements.
The procedure that was established for this project consists of manually recording the value from the LFD display at approximately six-second intervals until fifty values have been recorded.
The mean of the fifty readings is then considered to be representative of the exposure rate over the approxi-mately five-minute duration of the measurement.
The rate method has two main advantages.
- First, a short period. of sl time is~~for each reading; therefore, one can take measurements at several locations during a workday.
- Second, the variation of the
" exp'osure ra0eMMn also be measured.
As part of this method, the
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4 C
I J
Each instrument was calibrated by the manufacturer before shipment.
The calibrationgyf the instruments has been checked by project personnel using a Ra-226~iource.
- However, a rigorous recalibration procedure, has not yet been eptablished.
When an environmental radiation measurement is made, the sensor
- head, which contains the ionization chamber and the electrometer, is placed qn a tripod such that the center of the chamber is approximately one meter (3.3 feet) above the ground.
The control circuitry, read-out
- devices, and battery pack are in a separate control housing, which is electrically connected to the sensor head by a six-meter (20-foot) cable and is placed at least three meters (10 feet) from the sensor head.
The details of the operating procedure for the instrument are contained in the manufacturer's instruction manual.
ACCtDbss ~.
Because various read-out devices are included in the instrument, several methods of determining the exposure rate are possible.
Two methods have been used in this project.
The first method is referred to as the "rate"
- method, because the exposure rate is read directly from the LED.display.
The exposure rate value observed on the display fluctuates rapidly due to the random nature of radioactive decay.
Therefore,.several exposure rate readings must be averaged to obtain a meaningful measurement using this, method.
Furthermore, this must be done in a consistent manner in order to make valid comparisons among measurements.
The procedure that was established for this project consists of manually recording the value from the LED display at approximately six-second intervals until fifty values have been recorded.
The mean of the fifty readings is then considered to be representative of the exposure rate over the approxi-mately five-minute duration of the measurement.
f>>
~
II The rate method has two main advantages.
- First, a short period of
~
~J time is~gg~o~
each reading; therefore, one can take measurements at several 'locations during a workday.
- Second, the variation of the 4+~
exposure rate:eaii also be measured.
As part of this method, the I
I r'.
>Pi
standard deviation of the fifty readings is routinely calculated and recorded.+gAlso, the fiftyindividual readings are available if a detailed analysis of the distribution of these data is desired; The rate, method also has two main disadvantages.
- First, someone must be present during the measurement to perform the somewhat tedious task of recording the fifty individual exposure rate values.
Second, if a fluctuating source of radiation is present in the environment, a five-minute measurement may not be sufficient to quantify or even to detect the contribution due to that source.
The second method used to measure exposure rate utilizes the integrator and is referred to as the "integral" method.
Using this method, the accumulated exposure is read from the mechanical register, and the time over which the accumulation occurred is measured with a stopwatch or other timing device.
Since the mechanical register displays only integer values of exposure in microroentgens, care must be taken that the elapsed time measured with the timer corresponds to an integral number of microroentgen'ncrements.
The following procedure is used..
The instrument is allowed to warm up for approximately two minutes, after which the timer is started as closely as possible to the instant that the mechanical register is next incremented.
Generally, when only background radiation is present, the timer is started when the regi.ster is Xncremented'rom 0 to 1 pR.
The initial reading is
- recorded, and the instrument is allowed to-accumulate additional micro-roentgens.
At the end of the'measuremen't, the timer is stopped as closely as possible to 'the instant that the last microroentgen incre-ment is, recorded on the mechanical register.
The final register reading and the elapsed time are recorded.
The overall exposure rate during the measurement is calculated by subtracting the initial
.readinI+rom the final reading, and dividing The integral'ood has two main advantages.
is longer w1t'Xi~he integral method than with by the elapsed time.
First, the measurement time the rate method; therefore,
standard deviation of the fifty readings is routinely calculated and recorded. <also, the fiftyindividual readings are available if a
~f detailed analysis of the distribution of these data is desired; The rate method also has two main disadvantages.
- First, someone must be present during the measurement to perform the somewhat tedious task of recording the fifty individual exposure rate values.
Second, if a fluctuating source of radiation is present in the environment, a five-minute measurement may not be sufficient to quantify or even to detect the contribution due to that source.
The second method used to measure exposure rate utilizes the integrator and is referred to as the "integral" method.
Using this method, the accumulated exposure 'is read from the mechanical register, and the time over which the accumulation occurred is measured with a stopwatch or other timing device.
Since the mechanical register displays only integer values of exposure in microroentgens, care must be taken that the elapsed time measured with the timer corresponds to an integral number of microroentgen'ncrements.
The following procedure is.used.
The instrument is allowed to warm up for approximately two minutes, after which the timer is started as closely as possible to the instant that the mechanical register is next incremented.
Generally, when only background radiation is present, the timer is started when the register is incremented from 0 to l pR.
The initial reading is
- recorded, and the instrument is allowed to accumulate additional micro-.
roentgens.
At the end of the measurement, the timer is stopped as closely as, possible to the instant that the last microroentgen incre-ment is 'recorded on the mechanical register.
The final register reading and the elapsed time are recorded.
The overall exposure rate during the measurement is calculated by subtracting the initial" reading+>.', rom the final reading, and dividing by the elapsed time.
~IS~~.
The integral method has two main advantages. 'irst, the measurement time is longer witP,',the integral method than with the rate method; therefore,
'f
Table 1.
SUMMARY
OF DATA - DIRECT RADIATION LEVELS - BROWNS FERRY NUCLEAR PLANT
- Rate, Locat on No ean St
.'N 1%,'$.',:
10
.. 6.62 2-1 (t 3 g'1 7 ~ 47 N 2-2 '
'10 7.88 N 2-3 ll; 7.31 N 3-1
~ 11 8.29 N 4-2
- 12 9.72 N 5-1
..10 10.16 N52.
9 972 N 5-3
. 15 9.48 N 6-1 25,
- 8. 84 N 6-2 11 '.97 N 6-3 98 9.78 N 6-4 '4
- 10. 13 NNE 1-1 10 6.56 NNE 2-1 10 6.63 NNE 2-3 10 7.55 NNE 2-4
. 11 7.90'E 3-3 9
9.78 ANNE 3-4 10 8.49 NNE 4-1 ll 8.75 NNE 5-1 13 7.70 NNE 6-1 15
~
8.89 NE 1-1 10 6.75 NE 2-1 11 7.39 NE 2-2 12 7.75 NE 3-1 10 8.80 NE 4-1
. 10 7.33 pR h ev.
0.19 0.47 0.30 0.23 0.22 0.65
- 0. 24-0.42 0.41 0.30
- 0. 39 0.29 0.34 0.17 0.24 0.16 0.25 0.15 0.27 0.29
- 0. 34
- 0. 27
- 0. 14
- 0. 31
- 0. 19 0.58 0.22 Da No.
2 6.55 4
7.61 2
7.52 7.91 1
8.28 7
10.04 4
10.26 2
9.97 2
9.72 7
9.10 1
8.23 6
9.66 5
10.06 2
1 2,.
0 4
1 8
8
~ 4 3
1 0
2 6;66 6;45 7.48 9.57 8.41 8.74 7.83 9.22
'6. 78 7.85 9.07 7.38 0.33 0.62 0.24 0.21 0.18 0.24 0.02 0.30 0.22 0.28 0.18 0.10 0.47 0.21 0.25 0.27 0.08 0.34 Inte ral gR h Mean Std.
Dev.
Rate R/h No.
Mean Std.
Dev.
1 7.05 2
7.99 1.29 5
- 10. 03
- 0. 22 10 9.27
- 0. 39 3
9.0Q 0.36 7
9.72 0.38 1
6.86 1
7.83 1
6.67 1
- 7.92 Ni ht Inte ral, gR/k No.-
Mean Std.
Dev.
p
- .'g, (14 p
0 8
9.32 0.39 0
6 9.93 0.28 0
0 0
0 a 0 Std.
Dev.
~ Standard Deviation.
A i>>
g
~ ",
g$
pl l~3
~
g
~
~ ~T
~g
Table 1 (continued) 'UMMARY OF DATA DIRECT RADIATION LEVELS BROWS FERRY NUCLEAR PLANT 4.
NE 4
2~-jp.gy10< f-.9. 14 NE 5-1
( ~fPj.'0."
9.27 NE 6-1
'"10' 7.84 ENE 1-1 9 '.77 ENE 2-2 9.
6.60 ENE 2-3 10 '.24 ENE 3-.2
'10 8.54 ENE 4-1 14
'9.51 ElE 5-1 13 '.40 ENE 5-2 9
9.96 ENE 6-2
.11 8'28 E 2-1
'0.
7.12 E 2 2.
11 8 20 E 3-1 10
~ 6.86 E 3-2, 10, 8.39 E 4-1,,
'l7 7.41 E 5-1 15
'10. 19 ESE 1-1 10
'7.88 ESE 2-1 11 ':76 ESE 3-1 11 7.58 ESE 4-1 13 9.85 SE 1-1 16 9.60 SE 2-1 10 7.32 SE 3-1 'l 9.57 SSE 1>>1 16 8.59 SSE 2-1'2 6.14 S 1-1
'6 10.14 S 1-2 16 7.84 te uR/h
- 0. 17
- 0. 34
- 0. 11
- 0. 26
- 0. 15
- 0. 18
- 0. 26
- 0. 21
- 0. 36
- 0. 32 0.53
- 0. 17 0.20 0.25 0.23
- 0. 30 0.23
- 0. 35
- 0. 33
- 0. 29
- 0. 17
- 0. 90
- 0. 37
- 0. 19
- 0. 34
- 0. 21.
- 0. 86 1.19 Std.
Dev.
Ro.
1 3
1 4
2 1
2 8
5 1
1 3
2 1
2 9
9 1
0 1
7 2
3 6
1 2
1 2
Mean
- 9. 31-
- 9. 13 8.00 6.87 7.11 8.25 8.74 9.62 9.69 9.92 9.13 7.14 8.42 6. 8,1
- 8. 37 7.48 10.25
- 7. 86 7.61 9.88 9.47 7.02 9.51 8.68 6.27 11.01 8.90 ral
/h Std.
Dev.
0.62 0.33 0.98 0.26 0.13 0.41 0.27 0.08 0.42 0;28 0.20 0.21 1.75 0.04 0.14
'.23 0.08 No.
Ni ht Rate R/h Mean S td. Dev.
1 6.78 1
6.80 5
7.29 4
7.13 0.13
- 0. 11 1
8.21 9
6.84 9
7.70 9
10.05 1
10.16 9
7.56 8
9.92 1
8.54 8
6.22 1
11.09 0.23 0.44 0.25
- 0. 35 0.29
- 0. 12 Inte ral UR/h No.
Mean Std.
Dev.
j(
0 0
0 0
0 0
0 0
0 8
7.71 1
9.62 0
1 6. 1'2 0
- 0. 26
Table 1 (continued)
~
SUMMARY
OF DATA - DIRECT RADIATION LEVELS BROWNS FERRY NUCLEAR PLANT W 2-1 hhw 1-1 WNW 2-1
'7 18.
14 WNW 2-2 15 NW 1-1 NW 2-'1 NW 3-1 NW 3-2 NW 4-1 NNW 1-1 NNW 2-2 NNW 3-2 NNW 3-3 NNW 4-1 NNW 4-2 NNW 4-3 NNW 5-1
.NNW 5<<2 NNW 5-3 NNW 5-4 NNW 6-1 ll 10 12 10 12 10llll 10 10 10 10 15 10 10 14 14
,Loc~on No.,
'IA) y"-
"))8 SSW l-l'f 16 SSW 1-2 y<"7, SW l-l 't SW 1-2
'; 18 WSW l-l, 16 WSW 1-2 17 W 1-1 16 n$
't
~
Mean.
- 9.73 8;87
- 10. 60
- 9. 56
- 11. 49 9;41
- 13. 17 8.83
- 24. 23 6.99
- 9. 29
- 12. 30 8.22
- 9. 45
- 8. 43
'.31
- 8. 08
- 8. 25
- 9. 17 8.42 8.61
- 10. 00
. 8;71-
- 10. 20 9.54
- 9. 82
- 9. 67
- 10. 49
- Rate, gR/h Da 1.58
- 0. 86
- 2. 48
- 1. 20
- 2. 60
- l. 05
- 2. 88 0.69
- 9. 56, 0.48
'.47
- 2. 05
- 0. 24
- 0. 56
- 0. 28
- 0. 28 0.55
- 0. 35 0.
29'.
25
- 0. 36
- 0. 29
- 0. 40
- 0. 29
- 0. 28
- 0. 20
- 0. 75 0.29 Std.
Dev.
No.
1 2
1 2
1 3
1 2
3.
1 5
2 1
1 3
2 1
1 0
3 2
4 10.75 8.81 12.07 9.01 13.62
8.90.
- 15. 81 8.27 32.97 6.99
- 9. 93 12.62 8.44 9.34 8.08 9.26 8.30 8.49 9.28 8.50 10.21 9.59 10.62
- 9. 73 9.68 9.70 10.90 1.20 2.43 1.05
- 0. 35 4.64 1.13
- l. 93 0.27 0.70 0.46 0.63 0.35 0.45 0.71
- 0. 15 Inte ral, UR/h Mean Std.
Dev.
No.
9 85.
.9 9
5 9
2 5
5 5
5 5
5 5
5 9
5 Ni ht Rate gR/h Mean Std.
Dev.
11.07 12.64 14.09 15.71 35.72 7.55
- 9. 39 13.34 9.50 9.70 9.94 9.80 8.18 8.35 9.50 9.02
- 10. 13
- 10. 00 9.44 10.39 10.11 9.92 10.01 10.43 0.81
- 0. 16
- 0. 15
- 0. 15 0.33 0.33 0.35 0.11 0.09 0.33
- 0. 14 0.24 0.27
- 0. 1'4 0.34 0.31
- 0. 24 0.45 0.51 Inte ral, gR/h No.
Yiean,g Std.
Dev.
0 0 g:
0 0
0 0
0 0
0 9
8 2
8 0
1 0
1 1
0 1
0 5
2 0
0 9.54 9.84 10.16 9.92-
- 0. 14
- 0. 19
- 0. 17 0.38
, 8.65 9.19 10.39
- 9. 85
- 10. 17 9.98
- 0. 30 0.33
z.
DISCUSSION TEMPORAL VARIATION The background exposure rate at a given location varies slightly with time, mainly due to fluctuations in meteorological conditions.
These variations, are usually gradual,'taking place.over a period of several hours.
flowever, precipitation can cause an abrupt increase in the background due to the washout of radon decay products.
For this reason, data collection during periods of precipitation was avoided'.
The standard deviations presented in Table 1 for the daytime data provided an estimate of the day-to-day variation in the exp'osure rate at
\\
each location.
At most locations this variation was small.
From the data collected by the rate method, the standard deviations at 71 of the 83 locations were less than or equal to 0.75 pR/h.
At these 71 locations, the ranges of the rate measurements were less than 1 pR/h at 44 locations, between 1 and 2 pR/h at 24 locations, and greater than 2 pR/h at only three locations.
The largest
- range, 2.38 pR/h, was observed at NNW 5-4.
At the remaining twelve locations, the standard deviations varied from 0.86 to 9.56 pR/h, and the ranges in the rate measurements varied from 2.26 to.27.87 pR'/h.
The greatest variat'ion was observed at WNW 1-1, where the rate measurements varied from 8.20 to 36.07 PR/h.
This vari-.
I ation is too large to be due to fluctuations in the background alope.
1.ocation:WNW 1-1 is in very close proximity to the area of the plant where;low=reve.Vradioactive waste is packaged and stored until't is
'd
.~
shipped.'ll+g
.the'twelve locations except SE 1-'1'are close to the.
plant and on+he same side of the plant as the radwaste area.
The
~~
14
~.
0
measured exposure rates at these locations have been observed to decrease after a segment of radwaste has left the plant. It has been concluded 4:+!
that the radwaste contributed to the exposure rates measured at the locations in~he S,
~r'r
'ecause the exposure rates measured at these locations contained a
contribution due to the plant, these rates were excluded from comparisons with background exposure routes at other locations.
The standard deviation value of 0.75 1JR/h seemed to be a reasonable,'ut somewhat arbitrary, cutoff between the locations that were unaffected by direct radiation from the plant and the locations that were affected.
Location W 2-1 was included in the latter group, even though the standard deviation of the rate measurements made there was less than 0.75 pR/h.
This inclusion was made because fluctuations, in the exposure rate at that location seemed to be correlated with fluctuations in the measurements
, made at the other locations that were included.
Location SE 1-1 was not included in this group because it was well shielded from the radwaste
- area, and because the fluctuations in exposure rate at that location did not correlate with the fluctuations at the other locations.
- However, another source of radioactivity within the plant may have affected the exposure rate at SE 1-1.
~eggggmmewv
'if'he variation in the data collected hy the integral method at each location was similar to the variation in the data collected by the rate method.
As mentioned
- above, there were 71 locations where the standard deviations of the rate measurements were less than or equal to 0.75 pR/h.
Two or more integral measurements were made at 43 of these locations.
/
At two.of these locations, the standard deviations of the integral measure-ments were greater than 0.75 pR/h; 0.98 pR/h at FNE 2-2 and 1.13 pR/h at WNW 2-1. 'hese standard deviations were based on only two measurements at ENE&-.2 and three measurements at WNW 2-1.
At the 43 locations, the ranges o
tVe&ntegral measurements were less than 1 WR/h at 33 locations,
- v
+me,m
'll wv between 1 an~;.pR/h at seven locations, and greater than
- 2. pR/h at only one locatio~The largest range, 2.20 WR/h, was observed at WWW 2-1.
I
.iC
~
~
15
~
Te
Two or more integral measurements were made at seven of the twelve locations agre the standard deviations of the rate measurements were greater than'OC'75 lJR/h.
At six of these locations, the standard devia-tions of the integral measurements were greater than 0.75
)JR/h.
The one exception was at S 1-2 where the standard deviation was 0.08 pR/h.
This standard deviation was based on only two measurements.
The ranges of the inte'gral measurements at the seven locations varied from O.ll pR/h at S 1-2 to 6.56 pR/h at MNW 1-1.
The nighttime data, a summary of which is included in Table 1, were limited in quantity, but were sufficient to provide comparisons between daytime and nighttime measurements at a few locations.
A one-way analysis of variance (ANOVA) was performed on both the rate and integral data for each location where at least two measurements were made, both during the
~
day and at night.
In Table '2, the actual number of daytime and night-time measurements that were involved in each comparison is indicated.
For each comparison, the difference is presented as the average of the nighttime measurements minus the average of the daytime measurements.
Comparisons were made for 29 locations using the rate measurements.
For twelve. of these locations, the differences between the daytime and night-time, measurements were statistically significant.
For all twelve of these locations the average exposure rate was larger for the nighttime measurements than for, the daytime measurements.
The largest difference observed;
- however, was only 1.52 pR/h.
Comparisons using the integral measurements were made for only six locations.
For two of these locations, the differences between the day-time and nighttime measurements were statistically significant.
In each
- case, the average of the nighttime measurements exceeded that of the daytime measurements.
The largest difference observed was 1.10 pR/h.
For thr
=
ie six locations where comparisons were made using both the
'N rate and integral measurements, the results of the comparisons were not 6
consistent.
'T'other words, the comparison using the rate measurements 16
~
6q
ll
Table 2.,
COMPARISONS BETWEEN DATA COL'LECTED DURING THE DAY AND DURING THE NIGHT Rate Measurements Integral Measurements Location N 5-1 N 6-1 N 6-2 N 6-3 E 2-1 E 3-1 ESE 2-1 ESE 3-1 ESE 4-1 SE 2-1 SE 3-1 SSE 2-1
'NW 2-1 WNW 2-2 NW 2-1 NW 3-1 NW'-2 NW 4-1 NNW 2-2 NNW 3-2 NNW 3-3 NNW 4-1 NNW 4-2 NNW 4>>3 NNW 5-1 NNW 5-2 NNW 5-3 NNW 5-4 NNW 6-1 No-..-~
~Da
)
.a)v 10 25ll 98 10 10
.,llll 13 10 11 12 14 15 10 12 10 12ll 11 10 10 10 10 15 10 10 14 14 No.
~(Ni ht 5
10 3
7 5
4 9
9 9
9 8
8 9
8 9
9 5
9 5
5 5
5 5
5 5
5
.5 9
5
'ifference (Night-Day),
R/h
-0. 13
- 0. 43 1.12
-0.06
'.17
- 0. 27
- 0. 08
- 0. 12b 0.20 0.24 0.35
- 0. 08b 0.56 0.10 1.28 0.25 1.51 0.49 0.10 0.33
- 0. 60 1.52 0.00 0.73
- 0. 19 0.57 0.10.
0.34
-0. 06 7
3 2
5 2
No.
No.
~(Da )
~(N5 ht)
D fference~
(Night-Day),
~l z4 0.22 0.27 0.69
- 1. 10 0.44 0.30 a.
Significant difference at the 0.01 b.
Significant difference at the '0.05 level.
level.
17
showed a significant difference while the comparison using the integral measurements did not, or vice versa.
These discrepancies probably 4
occurred bee'ause of the small number of integral measurements that were made.
In all three of these
- cases, however, the differences between the average4.'of the nighttime measurements and the average of the daytime measurements were approximately the same for both the rate and the integral methods.
4
~4f4t It must be kept in mind that the comparisons between daytime and night-time measurements were based on. a small amount of data.
No conclusions can be drawn concerning the reasons why significant differences were found for some locations, but not for others.
These comparisons do
- indicate, however, that significant increases in background'evels can occur at night.
Therefore, if exposure rate measurements are made at night while the plant is operating, care must be taken to establish the proper background levels.
SPATIAL VARIATION The background radiation levels were observed to vary slightly from location to location.
This can be seen from the summary of the data presented in Table 1.
A close examination of the average exposure rates in Table 1 revealed what appeared to be a spatial trend in the measure-ments.
Specifically, the exposure rates at locations close to the plant
'eemed to'e lower than those at locations farther away from the plant.
To determine whether or not such a trend actually existed in the data, a
one-way ANOVA was performed with the six zones as the treatment groups.
The data from all the locations within eath zone were pooled.
The data from the locations in the S,
- SSW, SW, WSW, and W sectors, and from locations WNW 1-1 and NW l-l, were not included for the reasons stated in the previous section.
At many locations, the integral measurements or nightgime measurements were few in number or nonexistent; therefore, only raWP%i8%urements made during the day were included in this analysis.
r,
~.
pt 18 4I ~
tt
The mean and standard deviation for the measurements from each
- zone, as well as thgnumber of measurements, are presented in Table 3.
The infor-
'I mation in Tabte
.3 is arranged so that the mean exposure rates are in descending order.
The ANOVA indicated that there was a significant difference-"-'among the six zones at the 0.01 level.
To determine specifically where the difference or differences
- were, the mean from each zone was compared with the means from all the other zones using the Scheffe method.
The results of these comparisons indicated three distinct groups, such that there was no significant difference between the zones within each group, but the mean from each zone in a group was significantly different at the 0.01 level from the mean from any zone in the other groups.
The.groups were (1) zones 5 and 6, (2) zones 4 and 3, and (3) zones 1 and 2.
Therefore, one can conclude that, in general,
'the background radiation levels were lower at locations close.to the P
plant than at locations farther away from the plant.
Neasurements from sever'al locations 'did not follow this gener'al trend.
Therefore, a better grouping of the locations was sought.
A one-way ANOVA was performed on the same data as'n the analysis above, but with each locatfon as a treatment group.
The ANOUA indicated that there was
'I
, a significant difference among the locations at the 0.01 level.
- However, because there were a large number of locations and the means of the exposure rate measurements formed essentially a continuum'of values from 10.49 to 6.14 WR/h, grouping the locations was very subjective.
The rationale that was used to assign the groups was as follows:
(1) no comparison between two means within a group should show a significant difference at the 0.05 level using the Scheffe method, and (2) a compari-son between the largest mean in a group and any mean in the next group of smaller means should show a significant difference at the 0.05 level.
The result of this approach was the three groups presented in Table 4.
This arrangement of the locations is very convenient, as the ranges of the means in ttie'Threegroups are approximately the same.
The three groups" '""-'.""""'~ "
were identifiedas "High" (approximately 10.5 to 9 pR/h),
"Medium" 19
I
~
~
Table 3.
COMPARISON AMONG ZONES Zone r~
No. of
-Measurements 142
- Mean, gR/h 9.59 Std. Dev., a pR/h 0.77 198
- 9. 39 0.81 129
- 8. 91 0.95 135 8.60 0.83 91 7.81 1.21 209 7.55 0.82 a.
Std.
Dev.
Standard Deviation.
i ~
20'
~
~
Table 4.
LOCATIONS GROUPED BY EXPOSURF.
RATE
'Hi h Location NNW 6-1 NNW 5-1 E 5-1 N 5-1 N 6-4 NNW 4-2 ENE 5-2 FSF. 4-1 NNW 5-3 NNE 3-3 N 6-3 N 5-2 N 4-2 NNW 5-4 SF. 1-1 SE 3-1 NNW 5-2 FNE 4-1 N 5-3 NW 3-1 ENE 5-1, NW 4-1
'NW 2-2 NE 5-1 NNW 3-2 NE 4-2
- Meyn, pR)h
~Q.O. 49
- 10. 20
- 10. 19
- 10. 16
- 10. 13
- 10. 00
- 9. 96
- 9. 85
- 9. 82
- 9. 78
- 9. 78
- 9. 72
- 9. 72
- 9. 67
- 9. 60
- 9. 57
- 9. 54
- 9. 51 9.48 9.45
- 9. 40
- 9. 31
- 9. 29
- 9. 27
- 9. 17 9;14
'taedium Location NNE 6-1 N 6-1 NE 3-1 NNE 4-1 NPW 4-3 NNW 4-1 SSE 1-1 ENE 3-2 NNE 3-4 NW 3-2 NNW 3-3 E 3-2 N 3-1 FNE 6-2 NNW 2-2 ENE 2-3 NW 2-1 E 2-2 NNW l-l N 6-2 NNE 2-4 F.SF. 1-1
~ N 2-2 NE 6-1 NE 2-2 NNE 5-1 ESF. 3-1 NNE 2-3
- Mean, pR/h
- 8. 89
- 8. 84
- 8. 80 8.75
- 8. 71 8.61 8.59 8.54 8.49 8.43 8.42
- 8. 39
- 8. 29 8.28 8.25 8.24 8.22 8.20 8.08 7.97 7.90 7.88 7.88 7.84 7.75 7.70 7.58 7.55 Location N 2-1 F. 4-1 NF. 2-1 NE 4-1 SF. 2-1 N 2-3 E 2-1 WNW 2-1 F. 3-1 ENE l-l ESE 2-1 NE l-l NNE 2-1 N l-l ENE 2-2 NNE l-l SSF, 2-1
- Mean, pR/h 7.47 7.41 7.39 7.33 7.32 7.31 7.12 6.99 6.86 6.77 6.76 6.75 6.63 6.62 6.60 6.56 6.14 21
(approximately 9 to 7.5 pR/h),
and "Low" (approximately 7.5 to 6 pR/h).
COMPARISON AMONG INSTRUMENTS No schedule
.w8's used to determine which instrument would be used at a particular location on a particular day.
- However, a conscious effort was made to ensure that at no location was the same instrument used all or most of the time. It was assumed that, especially for any location where a large number of measurements were made, the order in which the instruments were used was essentially random.
Therefore, if there was a
difference in the performance of the instruments, this effect would be confounded with the day-to-day variation.
Only at location N 6-3 was a sufficient quantity of data collected to provide a comparison among the instruments.
To eliminate other possible sources of variation, only the data collected during the day using the rate method were used in this comparison.
A summary of these data is presented in Tab1e 5.
Only one measurement was made using the instru-ment that was loaned to the project, No.'-3590; therefore, this instru-ment was not considered in this comparison.
A one-way ANOVA was performed on the data.
This analysis showed that there was a significant effect at the 0.01 level due to variation among instruments.
The mean exposure rate for each instrument was compared to the means for the other four instruments using the Scheffe method~
No significant difference was found between instruments No. T-3512 and No.
T-3514 or between No.'-3517 and No. T-3516.
However, the mean for instrument No. T-3512 was significantly greater at the 0.01 level than the means for"No. T-3517 and No. T-3516; Also, the mean for instrument No. T-3514 was significantly greater at the 0.01 level than that for No.
T-3516, and was significantly greater at the 0.05 level than that for No.
T-3517.~The mean for instrument No. T-3513 was not significantly
+~~PP~-r different fr'om.any of the other means at the 0.05 level.
Because the mean exposure~te for No. T-3513 was much closer to those for No. T-3512--'y,...,
g and No. T-351'4, it was considered to be grouped with those two instruments rather than-'No.
T-3517 and No. T-3516.
22
~,
~
+
~
~ I', ~
Table 5.
COMPARISON AMONG INSTRUMENTS OF MFAN EXPOSURE RATES Instrument No.M'o. of Measurements
- Mean, pR/h Std. Dev.,
pR/h T-3512 7-3514 T-3513 T-3517 T-3516 26 18 21 14 18 9.95 9.88 9.81 9.58
- 9. 57
- 0. 20 0.27 0.27 0.25
- 0. 22 a.
Std.
Dev.
= Standard Deviation.
23
One possible explanation for this observed variation among the instru ments was ~ggested by the manufacturer.
Instruments No. T-3512, No.
2
'~Hi..
T-3513, and No.'- T-3514 may have been calibrated
- together, but at a different time than No. T-3516 and No. T-3517. It should be pointed out that the observed variation is within the manufacturer's specification, which is
+ 5 percent at 10 pR/h.
However, the fact that this small difference was statistically significant indicates that there may be benefits from a more refined calibration of the instruments.
Therefore, a
very rigorous calibration procedure should be established to (1) confirm the results of the analyses presented
- above, (2) bring the instruments into closer agreement with each other and with the correct exposure rate, and (3) determine if and how existing data, should be mathematically corrected to compensate for these observed differences.
COMPARISON BETWEEN INTEGRAL METHOD AND RATE METHOD The integral method and the rate method are described in the Materials and Methods section of this report.
The integral method should yield more precise measurements of the exposure rate than the rate method, simply because the measurement represents an average over a longer period of time, or equivalently, over a larger number of gamma-ray inter-actions.
.It is not expected, though, that one method is inherently more accurate than the other.
A statistical comparison between the r'ate and integral measurements should not show a difference between the two methods.
Included in the background data, summarized in.Table 1, are 262 cases where an integral and a rate measurement were made at the same time with the'ame instrument.
A paired t-test was performed on these data.. 'This an~lysis showed that there was a significant difference between the two methods at the 0.01 level.
The average difference in the exposure rate measurement values was only 0.0785'R/h, with 'the integral method producin -Che larger measurement values.
" The two methods=can
'also be compared by using a linear regression analysis.
'ne would,expk~gt that if the data were plotted, rate measurements vs 24
~
I
~
integral measurements, the data points would fall on a straight line whose inte~pt and slope could not be shown to be significantly different fro~m-:zero and one, respectively, because of the scatter in the data.
A~near regression analysis was performed on the data, resulting M the following prediction equation:
where and Y ~ 0.991457 X
Y = value via rate measurement, pR/h X = value via integral measurement, pR/h The multiple correlation coefficient, R
, was approximately 0.997.
The regression coefficient in the above equation was very close to one;
- however, a t-test on the coefficient indicated that it was significantly less than one at the 0.05 level.
Again, this indicates that there was a
significant difference between the integral and rate methods.
- ~
Some additional data were collec'ted to provide a comparison between the integral and rate methods.
During seventeen integral measurements,'the time, required for each microroentgen increment was recorded, thus providing a method of calculating the average exposure rate during each microroentge'n I
increment and the variation in the exposure rate during the entire integral measurement.
Also, during each microroentgen increment, a rate measure-
" ment was made.
In each
- case, the overall integral measurement value and the first rate measurement value were used in making the summary presented in Table 1, as, this would be the equivalent of the procedure normally followed.
The rate and integral measurement values during each micro-roentgen increment,
- however, provide several cases where both methods were used to measure the exposure rate during essentially the same period.
of time.
In Table 6, the means and standard deviations of the individual measurements made by both methods are presented for each of the seventeen 25 cases.
Paired t-tests were performed, comparing the rate and integral r
~ calcula~~~gurement values during each microroentgen increment.
The t-value, and th~.degrees of freedom 'associated with it', are presented
, for each.case@'n'Table 6.
)
Table 6.
COMPARISON RFTWEHN INTFt.:RAL AND RATE METHODS-S BmLTANEOUS lKASUREMENTS Instrument No.
T-3513 T-3513 T-3514 T-3514 T-3514 T-3514 T-3514 T-3517 T-3517 T-3517 T-3517 T-3517 T-35,17 T-3517 T-3590 T-3590
. T-3590
'*Integra1, PR/h
~ 9.533+.066
- 9. 396+.066
- 9. 718+. 103 9.647+.093 9.640+.092 10.043+.080 9.910+.067 10.086+.095 9.852+.093 9.584+.084 9.649+.045 9.922+.119
- 9. 489+. 098 9.505+.114
- 10. 036+. 129 "
9.409+..075 9.413+.091
- Rate, UR/h 9.554+.106 9.432+.077 9.718+.090 9.608+.101 9.639+.122 9.987+.097 9.860+.085 9.960+.103 9.717+.090 9.450+.101 9.536+.085 9.790+r135 9.349+.122 9.382+.102 9.904+.175 9.308+;076
- 9. 357+. 144
-1. 339 Ax
-4.400c OCOOO 3.053 0.068 4.217c 3 145d 14 47c 12 53c 8.090c 6.107 6.276 10.247 9.400 4.975 6.418 2.696 a ~
b.
C ~
d.
Mean
+ 'one standard deviation.
d.f. ~ degrees of freedom.
Significant at the 0.01 level.
Significant at the 0.05 level.'
26
Two observations can be made from Table 6.
- First, there= is little difference~<
any, in the standard deviations calculated for the two methods.
For both methods, the standard deviations are approximately 0.1 pR/h.
Thu's, it appears that one method is not inherently more precise than the other for measuring the exposure rate over the same period of time.'econd, the results of the t-tests indicate that the agreement or lack of agreement between the two methods may vary from instrument to instrument.
The 262 cases where, an integral measurement and rate measurement were taken at the same time were grouped according to instrument, and the paired t-test and regression
- analyses, described
- above, were performed on the data for each instrument.
The results of these analyses are summarized in Table 7.
The paired t-tests indicated, for all the instru-ments except No. T-3513 and No. T-3514, that the integral measurement values were significantly larger than the rate measurement values at the 0.01 level.
'The average difference between
'the two methods for those instruments exhibiting a significant difference, ranged from 0.1093 pR/h to 0.1590 pR/h.
The linear regression analyses showed similar results.
The regression
.coefficients for all of the instruments except No. T-3513 and No. T-3514 were significantly less than one at the 0.01 level, ranging from approximately 0.983 to approximately 0.988.
This also indicates that, for these four instruments, the integral measurement values were significantly larger than the rate measurement values.
A potential explanation, which was suggested by the manufacturer, for.
2 this observed difference is that the calibration of the integral and
/
rate circuitry may vary slightly from instrument to instrument.
The I
observed difference is less than two percent of the exposure rate, and is well NfEBT5'-the manufacturer's specifications.
The fact that these small differences were "statistically significant, however, indicates that there would be benefits if. the instruments were more finely
~r calibrated>~
27
gl
Table 7.
COHPARISON OF INTEGRAI. AND RATE HEAS}JREMENTS BY INSTRUN'.N7 Paired t-tests Re ression Anal ses 7.52 T-3513 T-3514 T-3516 T-3517 T-3590 70 0.781 28
-0. 294 43 46 5.30 7.68 4.59 Instrument No.
dMa
.sP T-3512 60 Avg. Difference, R/h 0.1198 0.0127
-0.0090 0.1093
- 0. 1326 0.1590 Re
. Coefficient 0.988046 0.997782 1.000411 0.987826 0.987023 0.983234 R
."99891405
. 9924 3529
.97529875
.98971596
.99854871
.98452253 a.
d.f.
~ degrees of freedom.
b.
Significant difference at the 0.01 level.
c.
Significantly less than one at the 0.01 level.
28
I g
~
PLUME DFTECTION MFTHODS i%en exposuFe rate measurements are made while the plant is operating, increases in the exposure rates due to radioactivity in the gaseous effluent from"BFNP are expected to be small in comparison with back-ground.
These increases might be difficult to distinguish from fluctua-tions in the background level.
Therefore, methods of identifying.and quantifying the contributioa to the exposure rate due to a gaseous effluent plume are being investigated.
It has been observed that the presence of a plume causes the exposure rate to fluctuate more rapidly than is observed when measur1ng back-ground alone.
This fluctuation results in a change in the distribution 3
of a set of exposure rate readings, such as the fifty readings that comprise a rate measurement.
This change in distribution is observed as an increase in the s'tandard deviation assoc1ated with the set of readings.
For every measurement obtained by the rate method, the mean and standard deviation of fifty readings were calculated.
This standard deviation is an estimate of the subsampling error, and should not be confused with the standard deviations reported in Table l and d1scussed on pages 14-16.
The subsampling standard deviations associated w1th the individual. rate measurements made at BFNP ranged from 0.24 to 0.77 pR/h, with the majority falling in the range of 0.3 to 0.5 pR/h..
A substantial increase in this statistic*for rate measurements made when the plant is in operation may indicate a contribution due to the plume.
The change in the distribution of a set of exposure rate readings also may be observed as a change in, the characteristics of a log-normal. plot of the data."
Typically, low-'level environmental measurements, such as measurements of baclcground exposure
- rates, have a log-normal distributio'n.
Therefore, a log-normal plot of such data should be a straight line.
A
'small co'ntribution due to a plume may cause a change in the shape of the,'
curve or a 'c ange in the slope of the straight-line plot, while causin'g Q(we ~
only a slight@ncrease'in the mean exposure rate.
Log-normal plots of '.-',.:.
8CP 4
several sets ef readings comprising rate measurements have been made.
29
y
~
These plots have indeed appeared as straight lines.
To date, this method appears toehold promise's a method for detecting the presence of a plume; however, quantification of plume effects using this method may,not be
'>~
possible in,yP.1 cases.
Another method of detecting and quantifying the effect of a gaseous effluent plume is based on a 3 x 3 Latin-square experimental design.
According to this design, measurements are made at three locations at the same time.
This procedure is repeated three times, once. while the wind is blowing in the direction of each location.
The assumption is made that, except for plume effects, variations in exposure rate with time are the same at each location.
In statistical terms, this is equivalent to assuming that there is no interaction between locations and observations.
The locations must be chosen care-fully so that this assumption can be made.
The locations should be far enough apart that the plume will not affect the exposure rate at more than'one location at a time.
However, the locations should lie within approximately a ninety-degree sector with respect to the plant, so that changing contributions due to direct radiation from sources within the plant would affect each location approximately equally.
For the same
- reason, the locations should be approximately equidistant from the plant.
The ANOVA model for this design is as follows:
RY 1I + L
+ 0
+
[P(38 1)/3]
ij (2).
where EYi
~ the expected value of the exposure rate at the location during the j observation, th th
~ the grand
- mean,
~ the effect of the i
- location, th
~ the effect of the 'j observation,
. th r
~ the. plume effect,
= '1 when i j, and 0 when igj.
- 30
The data are collected so that the wind is blowing toward location 1
during observation 1,
toward location 2 during observation 2,
and toward location' during observation 3.
Therefore, when i=), the in the mendel has a value of one, indicating a contribution due to
>EX the plume.
The average plume effect, P,
can be calculated by the following:
3
)
1 3'
6 '.. Yi, pR/h 1
i/j (3) where Y
= the measured exposure rate at the i location th during'he g
observation, AIR/h.
th The tea t for the hypo thesis tha t on the following statistic which there is no plume effect (P 0) is based is distributed F(1,3):
2 P 1,)
1 I
A A
A g
A 2
Yi) p
, Li 0 l P(36i) 1)/3 where and 3
Y
/9 i,j~l
,3 Li L
Y
/3 0
Y
/3.
i 1 J
(5)
(6)
(7)
As stated
- above, this analysis is dependent upon the validity of the assumption that there is no interaction between locations and 'observa-,
tions.~ ~is assumption is not valid, two types of errors could
~ '.," result.. The:analysis could indicate the presence of a-plume when in reality ther'eras no plume, or the analysis could indicate that there J
~
's a
~
1+
~
~
t f
was no plume when in reality a plume was present.
To investigate the validity of the assumption, the analysis was performed on five sets of background P~Fa.
Since the plant was not operating, there was no basis for assigning an assumed plume to a particular measurement.
Therefore, foi each set ck data, there are six distinct arrangements of the data, or ways to assign an assumed plume.
These arrangements are not independent of one another; nevertheless, the analysis was performed for all six arrangements for-,each of the sets of data.
The results of the analyses are presented in Table 8.
The three locations for each set of data also are indicated.
The first three sets of data were taken under the full constraints of the design.
The last two sets were not, however, because the locations were all in the NW sector and were not equidistant from the plant.
Since the plant was not operating, this should not affect the results of the analyses.
The data in all five sets were based on integral measurements which were
~ approximately one hour long.
For each of the six arrangements of each set of data, the calculated plume effect in microroentgens per hour, and the F-statistic associated with it, are presented in Table 8.
In all cases the plume effect was small, less than 0.3 pR/h.
In approximately half the cases, the calcu-lated plume effect was negative.
A negative plume effect has no physical meaning.
Also, in all cases, the F-statistic was less than 5.0, which is not significant.
Values of 10.1 and 34.1 for this statistic would be
~
significant at the 0.05 and 0.01 levels, respectively.
These.results, indicate that it is not likely that this analysis will show a signifi-cant plume effect when a plume is not,present..
The last two sets of data presented in Table 8 were taken at. the same locations.
Therefore, these data could be analyzed as a replicated 3 x
'3 factor4gg.
Such an analysis would provide a test on the significance of the 7nteNKion between locations and observations.
Such an analysis was performed~~.-these data.
The F-test for the interaction was not significant joe'n at the 0.25 level.
Although this test does not provide 32
Table 8.
RESULTS OF ANALYSFS ON BACKGROUND DATA TAKFN Locations:
ENE 4-1 ~A~'
4-1 ESE 4-1 NNW 5-4 NNF. 5-1 ENE 5-1 NNW 6-1 N 6-4 NNE 6-1 NW 2-1 NW 3-1 NW 4-1 ACCORDING TO THE PLUME DETECTION DFSIGN r
NW 2<<1 NW 3-1 NW 4-1 P)
~R/h
- 0. 120 F
- 0. 96 P,
IJR/h
-0. 288 F
4.26 P,
gR/h 0.040 F
- 0. 04 P,
pR/h 0.042 F
0.59 P,
vR/h
-0. 047 F
0.10
-0.130 1.20
-0.173 0.81
-0.025 0.02
-0. 028
- 0. 25
-0.082
- 0. 33
-0.035 0.06 0.232 1.83 0.200 1.70
-0.043 0.65
-0.122
-0. 165
- 2. 55
- 0. 045
- 0. 11 0.167 0.73
-0.235 2.99
-0.073 3.15 0.153
- 0. 122
- 0. 35 0.195 1.57 0.032
- 0. 32
-0.107 0;86 I.
0.62.
1.64 0.165 2.55
-0.058 "'.07
-0.175 1.15 0.072 2.88 0.203 4.92 33
~
<)
a
sufficient evidence to conclude that the interaction will always be insignificant, the results are encouraging in their support of the assumption of~o interaction between locations and,observations.
I'
~
g I
SENARY AND CONCLUSIONS The data collected between December 29,
- 1975, and June 25, 1976, characterized the nonoperational exposure rates at approximately 83 locations in the vicinity of BFNP. It was concluded that direct radia-tion from the plant, specifically from radwaste, affected the exposure rate measurements at twelve locations.
At the remaining locations, however, it is believed that the data are representative of background exposure rate levels.
At these locations, small day-to-day variations in exposure rate were observed.
At a majority of the locations, the ranges of the measurements were less than 1 (JR/h.
The largest range
, observed 'was 2.38 yR/h.
- Also, a significant increase in the background levels was observed at night at twelve of twenty-nine locations, but the largest increase observed was only 1.52 pR/h.
At the locations other than those affected by direct radiation from the 4
- plant, the means of the exposure rates varied from 6.27 to 10.49 PR/h.
A general trend in the'patial variation of exposure rate was found to be significant.
This trend'ndicated that the exposure rates at locations close to the plant were lower than the exposure rates at locations farther away from the plant.
Because of the many exceptions to this trend,,it was impossible to identify all the reasons for the spatial variation in the background.
It did appear, however, that the gravel in the parking lots reduced the contribution to the background from natural+pdioactive materials in the soil.
In addition tP'eharacteriz'ing the nonoperational exposure rates, the data provide'3, ~ means of evaluating the performance of the high-pressure 35
~
~
'onization chambers used to measure the exposure rates.
Small, but statistica@y significant, differences among the instruments and between the E'io modes of operating the instruments were observed.
This indicatg the'eed for a rigorous recalibration of the instru-
"~1 ments to e iminate these sources of variation from future measurements.
A recalibration procedure and schedule will be established.
Increases in exposure rate in the vicinity'of BFNP due to radioactivity in the gaseous effluent are expected to be small in comparison with background.
Therefore, methods of identifying and quantifying such a'ontribution due to a gaseous effluent plume were investigated.
One method of detecting the effect of a plume is ba'sed on observing a change in the distribution of a set of exposure. rate measurements.
A method of-detecting and quantifying the effect of a plume is based on a Latin-square experimental design.
Both of these methods appear to be useful.
In the next phase of this project, these methods will be evaluated using operational data.
I.
~
~
~t~ M "I'~C C
36
~
pg
~'
REFERENCES l.
"Operation Manual, RSS-111 Area Monitor System," Reuter-Stokes Instruments, Inc., Cleveland,
- Ohio, 1975.
2.
Personal communication, N. K. Gupta, Reuter-Stokes Instruments, Inc., Cleveland, Ohio, October 1976.
3.
Miller, K. N.,
C. V. Gogolak, and P.
D. Raft, "Final Report on Continuous Monitoring with High Pressure Argon Ionization Chambers Near the Millstone Point Boiling Water Reactor, " HASL-290, Health and Safety Laboratory,'ew York City, February 1975.
4.
Personal communication, J.
A. Broadway, Eastern Environmental Radiation Facility, Montgomery,. Alabama, February 1976.
'I 37
e,
~ i I