ML19294B605
| ML19294B605 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 01/14/1980 |
| From: | Novarro J LONG ISLAND LIGHTING CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 8003050137 | |
| Download: ML19294B605 (6) | |
Text
I%
'n LONG ISLAND LIGHTING COM PANY
/ fMC Mw4uamy SHOREHAM NUCLEAR POWER STATION P.O. BOX 618, NORTH COUNTRY RO AD e WADING RIVER, N.Y.11792 SNRC-458 January 14, 1980 Mr. Boyce Grier, Director Office of Inspection and Enforcement Region 1 U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pa 19406 I&E Bulletin 79-02 Shoreham Nuclear Power Ste icn - Unit 1 W. O. 44430/48923
Dear Mr. Grier:
Enclosed is the revised response to I&E Bulletin 79-02 con-cerning base plate designs using concrete expansion anchor bolts.
The report responds to all inquiries described in I&E Bulletin 79-02 including Revisions 1 and 2.
If you require any further information regarding the enclosed report, we will be pleased to discuss it with you.
Very truly yours,
- ].,.
/n wC J. P. Novarro
/ Proj ect Manager Shoreham Nuclear Power Station CKS:me cc:
Mr. Victor Stello, Dir Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 J. Higgins, NRC Site 8003050/3'"I FC.893 3
i RESPONSE TO ISE BULLETIN NO. 79-02 FIVISION 2 PIPE SUPPORT BASE PLATE DESIGN USING CRILLED-IN ANCHORS I&E BULLETIN 79-02 (Revision 2) raises questions with regard to pipe support base plate design. The following items are in response to inquiries concerning base plate flexibility, anchor bolt design loads and their factors of safety, cyclic loading, and Q.C. documentation for installation and inspection of base plates.
ITEM (1)
" Verify that pipe support base plate flexibility was accounted for in the calculation of anchor bolt loads".
The component support base plates are analyzed by modifying the simplified method of column base plates (Reference 3) with a load factor to determine the maximum bolt tension due to direct loads and prying effects of plate deformation. The load factors were determined from the proprietary parametric studies of rectangular and square plates, using the elastoplastic finite element analysis computer program ANSYS (Reference 4).
Plate flexibility, anchor stiffness, stiffening effect on member attached to the plate, as well as concrete flexibility, are represented in the model. The contact boundary conditions at the interface of the plate and concrete and plate and drilled-in anchors are satisfied in the solution.
The ANSYS 3 finite element package was used for analysis.
The element model considers pure plate bending, appropriate for the analysis of flexible base plates. The concrete and drillec-in anchors are both modelled with the " combination" gap elements which both model the stiffness of these components as well as represent the contact boundary conditions discussed previously.
Finally, forces are applied as couples and axial forces distributed to nodes of the attached member.
The bolt patterns and plate thickness are variables in the parametric study, and the load factor is the ratio of the high-est tension bolt load computed by finite element analysis to the maximum bolt tension load obtained from the simplified method.
The parametric study showed that the simplified method for column base plates (Reference 3) was conservative for low span to thick-ness ratios and unconservative for larger ratios where prying actions became significant. Plates with low ratios were con-servatively assumed rigid, while load factors were applied to plates with large span to thickness ratios.
Based upon results of the above parametrie studies, an acceptance criteria to determine whether the base plate should be considered flexible, more realistic than that presented in I&E Bulletin No. 79-02 (Revision 2), is used.
. ITEM (2) " Verify that the concrete expansion anchor bolts have the fol-loving mini =um factor of safety between the bolt design load and the bolt ulti= ate capacity determined from static lead test s..."
The anchor bolts used for co=ponent supports in the LILCO-Shoreha= plant are the "vedge" type concrete anchor bolts. The holding capacity of these anchor bolts is derived from the expansion of steel vedges against the sides of holes drilled in concrete (eg., Hilti Kvik-Bolts).
The tension / shear interaction diagram used for the anchor bolt design is shown in Figure 1, based upon the criteria given in Referer.ce 1.
The allevable tension loads for all anchor bolts are based upon the test results for Hilti Kvik-Bolts from an independent laboratory provided by the =anufacturer (Reference 2), using a =inimum safety factor of h.0 on pullout.
In addition to the use of Hilti Kvik-Bolts, PhilJips Red Head and Universal Thunderstuds are also used. Manufacturer's data shows that generally the Phillips Red Head bolts have a higher pullout capacity than the Reference 2 data.
The data available for the Thunderstud type bolts indicates that the loads are lover than those defined in the Reference 2 data for selective bolts sizes. Based on a concrete cc=pressive strength of h,000 psi, the factor of safety against pullout for these selective bolt sizes vould be a mini =um of 3.0.
This is in agreement with the design require-ments of ACI 3h9-76 " Code Require =ents for Nuclear Safety Related Concrete Structures", Appendix 3, Section B.7.2.
The balance of Thunderstuds and all other vedge-type anchor bolts used in the Shorehan Plant have a minimum factor of safety against pull-out of h.0.
A recent test program to determine actual in-place concrete co=pressive strengths of S eismic Category I structures has been completed. The test results show that 100% of the concrete represented by these tests has a ec=pressive strength in excess of 5,000 psi. Therefere, as noted above, an additional con-servatism has been applied to the stated facters of safety by the utilization of a design ec=pressive strength of k,000 psi.
In the design of anchor bolts for the Shoreham plant, specifications of minimum embed:ent, minimum spacing, minimum edge distance, and mini =mn concrete cocpressive strength (fe) are incorporated to provide assurance that use of these allevable tension loads vill
=aintain the mini =un factors of safety as outline above.
If these specifications cannot be ret, allowables are reduced linearly with respect to the reduced dinension (e= bed =ent depth, bolt spacing, etc.).
4 ITEM (3) " Describe the design requirements, if applicable, for anchor bolts to withst and cyclic loads..."
Industry test results of concrete anchor bolts subjected to cyclic loadings conclude that bolt integrity is unaffected by cyclic loadings as 1c.g as bolts are properly " set" during inst allation. The bolt " set" and a resulting bolt preload is achieved by applicantion of the installation torques specified in SUPS-1 procedures.
ITEM (h) " Verify frc= existing QC documentation that design requirements have been =et..."
k (a) Cyclic leadings have been addressed in Item (3) above.
Verification that installation requirements are met is accc=plished as described in Ite: h (b).
h (b) Field Quality Control procedure QC-ll.h requires inspection of anchor bolts for Category I pipe supports and restraints. The inspection ensures that bolt diameter and length, embed =ent depth, and installation torque (and thus cyclic load capacity) are in accordance with design require-ments.
This precedure has been Lnplemented for all Category I anchor bolt installations, thus verifying the design require-
=ents are =et.
ITIM (5) "Deternine the extent that expansien ancher bolts were used in concrete block (=asenrey) valls to attach piping systems..."
A review of Seismic Category I and other safety related piping systems has indicated that none of these syste=s are attached to concrece block walls.
ITEM (6) " Determine the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates."
Use of expansion anchors in structural steel shapes other than base plates in Seismic Category I piping systems is limited to small bore (2 inch and under) piping systems.
A Stene & Webster technical guideline, containing several standard, pre-qualified designs of supports for small bore piping, includes a support of the type described in Ite= (6) of ILE 79-02, Revision 2.
This standard support consists of a 5" x 9" channel secured to concrete by 3/h inch vedge-type anchor bolts through the channel web and equally spaced along the longitudinal center line. It is the only pipe support type involving the use of anchor bolts in structural me=bers other than base plates in Seismic Category I piping systems.
This standard pipe support was revieeed in accordance with existing approved methods for base plate stiffness evaluations as discussed in Ite (1) above and found to be satisfactory.
s.1
.s ;
=.
.a t J
^J t,o )
~
s
(
M.
u)
D
~
m_.A
. d, a
G J
nl ^v ii ct '
.M l
- o. c.
w.a a C.
4
..J. :
d.
I**'.;)
{*
Q I
.a u LJ '*
J
.2
(.e ui
- t.i n Q
414 f
if. b
(.
- i,. a ib r; g
,a
-,. 1 i, a
<s O.,
~
y g'
l Lt.
+
,a4 J
- + = -
d I).1 ;,-<3 U i.'. )
i g
,.s i.l '..
' *4
' L.
I' Q
e;
,i. b
',1 -.. !
\\
ll
. 4 _T
,y
..J b U) g/d' i n;1 iu 4
,,3 J.*
H
.2
/
E*
.I r
. '
- Y,i
.V-PJ I.','IHD300 '![
O I
- ] 21 T-*
Q
[
w
'N
.i a
-j px
. 3. ~ g,._;
..y y
.. -.,...,,,4 i L s'.s 't 1.1 t
- ' 1 a:
3+
- - e il II !!
ll
=-
3 n
- U.
t, M-
..?
H ra. r; o r-
- j q
C-U2 p
Uj O
o o
o 7
j l
-f a
sq i
I l
l l
_f.
_ I,_ _..!'_ _.
0 a
I e
i 1
j i,
t.. _ !.__ _.r'.,%
,I.
,_I i
l.
I c3
,)
t l
l j
{ N, l
' F-o, l
a "1
l, _. \\ w.i _,.. _.. !
O,,
l 1
8 I
j.
. _ /(. __
i i4 o
e-si j
/. g _ _;._ t
_{
W c.3
, n g r
. _..i _.
[
I
's
. er.
',,6-
- /' I
!\\
i a
i i---7, r i '.i c$ r I
l
/
l 1
_ /_ _,.li,_
l 6
I W, ' '.,, of cia n
l r., a u. ?. ' t u, I./
I m"
I 1.
l l o
_l_.._p..__
)
. '.c3 ul i3
..a o,,
,3 y
+
8 O,
0,,
j v
i l
. L... _ {1 _.
I y
'J ia o
l
_*'a N
i
- o 'r
.g
! ts)
{
, e, m..
_ I. _._.. i. _
l
,3 i o o
1.,
I l
s a-
. 'an
.. r ir.
i I
I l
4
.2
.., e.c si *
.2 t.1 t
1 o
t e..-o.4w>
=
o o
o o
o o,
o.,
o e
n o
o c.
m s
y y
n O
.L /J. - NOi'3 N 3 i L
/
- 3 D
g -
4
- 7
'{
4g
- .gp+
- ======.m e
- eew'e
_y, a
P+**,-
e ew s.ms.emp-e>**
9 e-**.a.,*
g
. - = -[
"q #
[
3 4 I
- F gg--
T
[p 7g I
g* =. =
yg, ggh
[_
g
.a.
f u.F r.' 2.::C.L :
O 1
I' :6ct:in, P. J. Slutter, n. C., f u:he r, J.
a.,
"H
- . nt Steel Anenor Under Coc'oined Loading", AISO Engineer Joarnal, Secan i quarte:, 1973.
abbot A. Ha4.s Testing Labora torica, Re; o r t :;o. d78;.. " Summa ry nepo r t. _
KWIK-3olt Testing Program", I'.arx, 1977.
3 Blodgett, c.
U.,
' resign of Welded Struc tures", The James F. Lincoln 'a'elding Foundation, 1972.
4.
DeSalvo, G.
J., and S.eancon, J.
A., "A!!SYS User's.t nual", S.canson Analysis System, Inc., 1972.
._e 6
J U J; o
JJ1 }
l o
o 4
- 5M*% % QW.'.L*emee.,6,
- /'
.f
,,o,.9
- p****ea
-.a sy m ge. sg.
_a
^ ~
f
,e e,
.