5 - tabatabaie
TRANSCRIPT
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
Recent Advances in Seismic Soil-Structure
Interaction Analysis of NPPs
Mansour Tabatabaie, Ph.D., P.E.
SC Solutions
NEA/CSNI-IAGE / IAEA ISSC
SSI Workshop
Ottawa, Canada
October 6-8, 2010
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
SSI ANALYSIS PROCEDURE
Seismic soil-structure interaction (SSI) analysis of nuclear power plants
(NPPs) in the United States is often performed in the frequency domain
using SASSI. This enables the analyst to properly:
a) Address the effects of wave propagation in an unbounded soil
media
b) Incorporate strain-compatible soil shear moduli and damping
properties
c) Specify input motion in the free field using the deconvolution
method and/or spatially variable incoherent ground motions
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
SSI ANALYSIS PROCEDURE
The original code was published in 1981 and consisted of 6 program
modules. Over the past 30 years, the program SASSI has evolved. A
current version of the code incorporates many enhancements that have
culminated in 28 program modules that perform a variety of tasks.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
LAYOUT OF ORIGINAL SASSI CODE
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
TAPE
2 SITE
CNTRL
POINT
MOTOR
HOUSE
TAPE
3
TAPE
1
TAPE
4
TAPE
9
TAPE
8
TAPE
8
TAPE
8
COMBN8 TAPE
8
TAPE
4
TAPE
4
MOTION STRESS
RANDOM
TAPE
12
TAPE
14,15
TAPE
12
CONVER
TAPE
8n
FBASE
TAPE
1
TAPE
5,10 AXSYM
TAPE
8
ANALYS
MATRIX
LOADS
TAPE
5 SOLVE
TAPE
6
TAPE
10
TAPE
7
TAPE
5 RIMP
PARTIAL LAYOUT OF MTR/SASSI PROGRAM
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
LARGE-SCALE SSI MODEL
Seismic response of NPPs in the United States is often required for
frequencies up to 33 Hz. In addition, NPPs founded on hard rock in the
Eastern United States are now required to be analyzed to frequencies up
to 50 Hz.
For a typical nuclear island about 100m x 100m in plan dimensions,
embedded 10m in engineered backfill (Vs = 250 m/s) and founded on
hard rock, 3-D detailed FE SSI analysis using SASSI requires:
> Max soil element size ~ 250 / 5 / 50 = 1 m
> No. of interface soil nodes ~ 100 x 100 + 4 x 100 x 10 = 14,000
> No. of virtual soil nodes ~ 100 x 100 x 10 – 14,000 = 98,600
There could another 60,000 nodes in the structure model to provide
adequate mesh refinement to extract response spectra.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
CONVENTIONAL SASSI MODELING &
ANALYSIS CONSTRAINTS
Seismic SSI analysis of NPPs using SASSI has had two main constraints
in the past:
a) Because of large storage and processing requirements, SASSI has
been constrained to coarse soil and structure FE models, which has
made it difficult to address the high frequency passing requirements
for SSI analysis.
b) Because SASSI uses frequency domain procedure, it is limited to
equivalent linear systems, which makes it difficult to address local
nonlinear effects in the structure such as base sliding and/or uplift,
component isolation, etc.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
HOW TO ADDRESS PROBLEM SIZE ?
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
LARGE CORE SOLUTION (LCS) MODEL
The LCS model takes advantage of modern computer technologies,
which now makes it possible to efficiently analyze large-scale, deeply-
embedded nuclear island models in SASSI.
Advantages of LCS:
a) Total SSI system can be analyzed in one step.
b) Provides highly efficient and accurate solution.
c) Eliminates large file storage requirements.
d) Structure model can be a duplicate copy of corresponding FE
model used for design without need for renumbering the nodes
and/or elements. This facilitates model development, translation,
calibration and maintenance for SSI analysis.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
Plan View of EPRTM Nuclear island
Nuclear Island
APPLICATION OF LCS MODEL TO LARGE-SCALE
NUCLEAR ISLAND MODEL
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
0
10
20
30
40
50
60
70
80
15 20 25 30
Density (kN/m3)
Dep
th B
elo
w G
rou
nd
Su
rface (
m)
1u
2u
3u
4u
5u
5a
1n5a
1n2u
2n3u
3r3u
2sn4u
Extension of
generic soil
profiles
0
10
20
30
40
50
60
70
80
0 3000 6000 9000
Vp (m/s)
Dep
th B
elo
w G
rou
nd
Su
rface (
m)
1u
2u
3u
4u
5u
5a
1n5a
1n2u
2n3u
3r3u
2sn4u
Extension of
generic soil
profiles
0
10
20
30
40
50
60
70
80
0 1000 2000 3000 4000
Vs (m/s)
Dep
th B
elo
w G
rou
nd
Su
rface (
m)
1u
2u
3u
4u
5u
5a
1n5a
1n2u
2n3u
3r3u
2sn4u
Extension of
generic soil
profiles
GENERIC SOIL PROFILES & PROPERTIES
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5 10 15 20 25
Time (sec)
X-A
ccele
rati
on
(g
's)
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5 10 15 20 25
Time (sec)
Y-A
ccele
rati
on
(g
's)
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5 10 15 20 25
Time (sec)
Z-A
ccele
rati
on
(g
's)
ACCELERATION TIME HISTORIES OF
REFERENCE EUR-SOFT MOTIONS
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.1 1 10 100
Frequency (Hz)
Sp
ectr
al
Accele
rati
on
(g
's)
X-Dir.
Y-Dir.
Z-Dir.
Damping = 0.05
ACCELERATION RESPONSE SPECTRA OF
REFERENCE EUR-SOFT MOTIONS
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
STCICK VS DETAILED FE SASSI MODEL
EPRTM NUCLEAR ISLAND
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
SASSI FOUNDATION MODEL OF
EMBEDDED EPRTM NUCLEAR ISLAND
El. -0.25m Sidewalls Not Connected to Soil
Sidewalls Not Connected to Soil
SB 2/3 SB 4
RB
3 4
5 6
7
8 9
10 11
Tendon Gallery Sidewall Nos.
FB SB 1
El. -11.85m
NI Basemat
2
NAB
AB
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
EXCAVATED SOIL MODEL OF EMBEDDED
EPRTM NUCLEAR ISLAND
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
Case
No. Soil Case Reference EUR Outcrop Motion
Analysis
Case
1 1u Soft 1u-s
2 2u
Soft 2u-s
3 Medium 2u-m
4 3u Medium 3u-m
5 4u
Medium 4u-m
6 Hard 4u-h
7 5u Hard 5u-h
8 5a Hard 5a-h
9 1n2u Soft 1n2u-s
10 2n3u Medium 2n3u-m
11 2sn4u Medium 2sn4u-m
12 3r3u Medium 3r3u-m
13 1n5a Hard 1n5a-h
SSI ANALYSIS CASES
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
MAXIMUM ACCELERATION CONTOURS IN X-DIR.
EPRTM NUCLEAR ISLAND
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
MAXIMUM ACCELERATION CONTOURS IN Z-DIR.
EPRTM NUCLEAR ISLAND
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
COMPARISON OF MAXIMUM ACCELERATIONS
(SOIL ANALYSIS CASE 2SN4U-M)
Location Elev. (m) X Y Z
Center of NI Basemat -11.85 0.262 0.224 0.319
Reactor Building IS +5.15 0.379 0.320 0.374
Reactor Building IS +19.50 0.513 0.419 0.388
Safeguard Building 1 +21.00 0.478 0.356 0.399
Safeguard Building 2/3 +16.30 0.400 0.433 0.413
Safeguard Building 4 +21.00 0.340 0.335 0.394
Fuel Building +4.20 0.300 0.364 0.298
Reactor Containment Bldg 58.00 0.869 0.734 0.516
Reactor Shield Bldg 61.40 0.598 0.679 0.490
Location Elev. (m) X Y Z
Center of NI Basemat -11.85 0.277 0.210 0.318
Reactor Building IS +5.15 0.347 0.258 0.341
Reactor Building IS 19.50 0.421 0.391 0.366
Safeguard Building 1 29.30 0.564 0.502 0.501
Safeguard Building 2/3 12.00 0.411 0.409 0.446
Safeguard Building 4 29.30 0.580 0.621 0.556
Fuel Building 3.70 0.350 0.294 0.357
Reactor Containment Bldg 58.00 0.738 0.620 0.893
Reactor Shield Bldg 61.40 0.843 0.854 0.578
Stick
Model
Detailed
FE
Model
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
COMPARISON OF ACCELERATION RESPONSE SPECTRA
(SOIL ANALYSIS CASE 2SN4U-M)
Top of Reactor Containment
Bldg., Eelv. +58.0 m
0.0
1.0
2.0
3.0
4.0
5.0
0.1 1 10 100
Frequency (Hz)
X-S
pe
ctr
al A
cc
ele
ra
tio
n (
g's
)
Stick ModelDetailed Model Reference Outcrop Motion
Damping = 5%
0.0
1.0
2.0
3.0
4.0
5.0
0.1 1 10 100
Frequency (Hz)
Y-S
pe
ctr
al A
cc
ele
ra
tio
n (
g's
)
Stick ModelDetailed Model Reference Outcrop Motion
Damping = 5%
0.0
1.0
2.0
3.0
4.0
5.0
0.1 1 10 100
Frequency (Hz)
Z-S
pe
ctr
al A
cc
ele
ra
tio
n (
g's
)
Stick ModelDetailed Model Reference Outcrop Motion
Damping = 5%
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
COMPARISON OF INTERSTORY SHEAR FORCES
& OVERTURNING MOMENTS
(SOIL ANALYSIS CASE 2SN4U-M)
Shear, Vx
-20
-10
0
10
20
30
40
50
60
0 500 1,000 1,500
Vx (MN)
Ele
vati
on
(m
)
Detailed Model Stick Model
Moment about Y-axis, My
-20
-10
0
10
20
30
40
50
60
0 10,000 20,000 30,000 40,000
My (MN-m)
Ele
vati
on
(m
)
Detailed Model Stick Model
Shear, Vy
-20
-10
0
10
20
30
40
50
60
0 500 1,000 1,500
Vy (MN)
Ele
vati
on
(m
)
Detailed Model Stick Model
Moment about X-axis, Mx
-20
-10
0
10
20
30
40
50
60
0 10,000 20,000 30,000 40,000
Mx (MN-m)
Ele
va
tio
n (
m)
Detailed Model Stick Model
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
CONCLUSIONS
a) Stick models are capable of determining global seismic responses, but
they can lead to excessively conservative results in the vertical
direction due to the limited number of modes that can be modeled
b) Detailed FE models capture local responses, thus eliminating the need
for modeling single DOF oscillators.
c) Effects of the basemat flexibilities can be considered in the detailed FE
models.
d) Meshing can be made sufficiently small in detailed FE models to
capture the response due to high frequency input motions.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
HOW TO ADDRESS LOCAL
NONLINEARITIES ?
a) Base sliding and/or uplift
b) Side soil debonding
c) Component isolation
d) Other local nonlinearities
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
DISTRIBUTED PARAMETER FOUNDATION (DPF) MODEL
The DPF model is a hybrid frequency/time domain procedure that allows
the structure to be partitioned from the total SSI system and analyzed in
the time domain while the foundation media is modeled using the
frequency-domain procedures.
DPF method involves four basic steps:
a) Calculating dynamic impedance at each foundation interaction node
from soil reaction forces and interaction displacements in the
frequency domain using SASSI.
b) Developing equivalent simple-damped oscillators with constant
parameters (spring, mass and dashpot) representing the dynamic
impedance functions obtained in “a”.
c) calculating foundation scattering motions at the same interaction
nodes from SASSI.
d) implementing the results as boundary conditions in the time-domain
dynamic response analysis of the structure.
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
DPF MODEL IN SASSI
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
FLOW DIAGRAM OF LINEAR SSI ALIGNMENT
SASSI Linear
Seismic SSI Model Target Linear Solution
Scattering
Motion
Dynamic
Impedance
Functions
Linearize:
KMC Model
Linear Seismic SSI
Model
Time-Domain Linear
Solution
Check
Alignment
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
FLOW DIAGRAM OF DPF MODEL IN SASSI
Typical In-Structure Response
Primary Containment
Reactor Building
Foundation
Diameter = 40 m
52.8 m
13.5 m
(Embedment)
Foundation Base slab
Node 18241
Node 17091
Node 17284
Node 203
Node 25
Node 16262
X
Y
Z
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0.01 0.1 1 10 100
Frequency (Hz)
X-A
ccele
rati
on
(g
's)
. SASSI, One-Step
ADINA, KMC
NODE 18241
Damping = 5%
0.0
0.5
1.0
1.5
2.0
2.5
0.01 0.1 1 10 100
Frequency (Hz)
X-A
ccele
rati
on
(g
's)
. SASSI, One-Step
ADINA, KMC
NODE 17091
Damping = 5%
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
NEAR FIELD INELASTIC SPRINGS
FOR MODELING BASEMAT SLIDING AND/OR UPLIFT AND
SIDEWALL/SOIL DEBONDING
P
U = Ue + Up
P
Ue
P
Up
= +
U = Ue + Up
Py
Pu
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
FLOW DIAGRAM OF NONLINEAR SSI ALIGNMENT
Scattered
Motion
Linearized
KMC Model
Aligned Linear
Seismic Model
Time-Domain Nonlinear Seismic Model
Nonlinear Near-
Field Springs
SC SOLUTIONS Copyright © 2010 SC Solutions, Inc., All Rights Reserved IAEA/NEA
Soil Structure Interaction (SSI) Knowledge and Effect on theSoil Structure Interaction (SSI) Knowledge and Effect on the
Seismic Assessment of NPPs Structures and ComponentsSeismic Assessment of NPPs Structures and Components
THANK YOU
FOR YOUR ATTENTION
QUESTIONS ?