ML19242D054
| ML19242D054 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/08/1979 |
| From: | Eric Turner HOUSTON LIGHTING & POWER CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| SFN:V-0100, SFN:V-100, ST-HL-AE-366, NUDOCS 7908140441 | |
| Download: ML19242D054 (3) | |
Text
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I Houston Lighting 1
& Power h
Company f[4b!)IU August 8, 1979 Electric Tower ST-HL-AE-366 PO Box l700 a
2filli'.h N llouston. Texas 77001 SFft: V-0100 Mr. Doninic B. Vassallo Assistant Director Division of Project l'anagcrent U. S. Nuclear Regulatory Conmission 1717 H. Street Washington, D. C. 205S3
Dear Mr. Vassallo:
South Texas Project Unitt 1&2 Docket fios. STN 50-498, STN 50-499 Soil Structure Interaction Analysis Procedures for Category I Structures of the South Texas Project Attached is an outline of the proposed p* aced res to Lc employed by Houston Lichting & Power Company in per~srming soil structure inter-action analysis for Category I structures at the South Texas Project.
These procedures, developed in response to NRC cuestion SEB 130.12, were discussed with Messrs. E. Licitra and R. Gt pta t< your office on August 4, 1979, and were telecopied to Dr. Gupta on August 7, 1979.
Should you desire additional information please contact Mr. L. R.
Jacobi at (713) 676-7953.
Ver' truly yours, O
- . R. fW E. A. Turner Vice President Power Plant Construction
& Technical Services LRJ:bf Attachment cc: Without Attachment Director, NRC Office of Inspection & Enforcement M. D. Schwarz (Baker & Botts)
R. Gordon Gooch (Baker & Botts)
J. R. fiewman (Lowenstein, Newman, Reis, Axelrad & Toll)
D. G. Barker A. J. Granger R. A. Frazar 7908140<oy 4 g,/
i, 1
Soil-Structure Interaction Analysis procedures for Category I structures of South Texas Project 1.
Calculations of equivalent soil-spring constants and damping coefficients Fonnulas in the following papers will be followed:
a.
Horizontal and Rocking Motions
" Coupled Horizontal and Rocking Vibraticn of Embedded Footings" by Eeredugo and Novak, Canadian Geotechnical Jcurnal, 9,447 (1972).
b.
Vertical Motion
" Vertical Vibration of Embedded Footings" by Novak and Beredugo Journal of the Soil-Mechanics and Foundations Division SM-12, December 1972.
c.
Torsional Metion
" Torsional and Coupled Vibrations of Embedded Footings" by Novak and Sachs Earthquake Engineering and Structural Dynamics Vol. 2, 11-33 (1973).
2.
No effective soil mass will ne added.
3.
Shear Modulus Maximum shear modulus (at 10 ': strain level)
~
and 75% of maximum shear modulus will be evaluated and results compared for some cases.
4.
Time history modal superposition and strain energy weighted modal dcmping will t,e used.
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5.
Time History Input fiction o For surface structures - Time histories whose response spectra envelope those in Regulatory Guide 1:60 will be used as input to the base of the soil springs.
o For deeply embedded structures - Time histories simulating Regulatory Guide 1.60 Design Response Spectra will be modified to take into account the effect of deep embedment.
As an example, the procedures suggested by Kausel, Wt.itman, Morray, and Elsabee in the following papers may be followed:
"The Spring Method for Embedded Foundations" in !!uclear Engineering o
and Design, Vol. 48, 1978 and
" Dynamic Analysis of Embedded Structures" SMIRT conference, 1977 e
paper k2/6.
6.
One set of soil properties will be used (no variation of soil pro-perties over a range) and the peaks of the calculated Floor Response Spectra will be shifted by + 15%.
7.
Only 21 damping ratio will be used to generate Floor Response Spectra for comparison, unless the new results exceed the existing results.
For this case, other damping ratios will also be used.
101
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