1. Patricia M. Clayton University of Washington
Resilient Steel Plate Shear Walls: Analysis of Performance Using OpenSees and TeraGrid Resources
Patricia M. Clayton
University of Washington
Jeffrey Berman (PI)
Laura Lowes (Co-PI)

2. NEES-SG: SPSW Research
Jeff Berman and Laura Lowes
Tasks:
Develop a resilient SPSW
Develop performance based design tools for SPSW
Develop a new model for SPSW web plates
Explore the behavior of coupled SPSWs and develop design recommendations
Michel Bruneau
Larry Fahnestock
K.C. Tsai
Jeff Dragovich
Rafael Sabelli
Sponsored by NSF through the George E. Brown NEES Program

3. What is a Resilient Steel Wall?
Combines benefits of Steel Plate Shear Walls (SPSWs) with self-centering technologies
SPSW provides:
Ease of construction
High strength and initial stiffness
Ductility
Yielding over many stories
Replaceable energy dissipation elements (steel plates)
Post-Tensioned (PT) Connection provides:
Self-centering capabilities
Quick return to occupancy after earthquake

4. Conventional SPSW Behavior
Resists lateral load through development of Tension Field Action
angle of
lateral
inclination
load
HBE a
tensile
stresses
Web plate
VBE
HBE
diagonal
Courtesy of Berman and Bruneau
folds

5. Conventional SPSW Behavior
Idealized hysteretic behavior of SPSW with simple HBE-to-VBE connections:
VSPSW
Unloading
Plate yields D
Low Stiffness
1st Cycle
2nd Cycle

6. PT Connection Behavior
Provides self-centering capabilities
Connection is allowed to rock about its flanges
PT remains elastic to provide recentering force
Requires some energy dissipation
Examples from previous research:
Yielding angles (Garlock, 2002)
Friction devices (Iyama et al., 2009; Kim and Christopoulos, 2008)
Garlock (2002)
Iyama et al. (2009)

7. PT Connection Behavior
Nonlinear elastic cyclic behavior of PT connection:
VPT
Connection
Decompression qr D
1st Cycle
2nd Cycle

8. Combined System: Resilient SPSW
VSPSW
VPT D D
VR-SPSW
Unloading
Plate yields
Connection
Decompression
Plates Unloaded
1st Cycle
2nd Cycle D
Connection
Recompression

9. Performance-Based Design
V2/50
D20/50
First occurrence of:
PT rupture
Excessive PT yielding
Excessive frame yielding
Excessive story drifts
Collapse
Prevention
V10/50
D10/50
First occurrence of:
PT yielding
Frame yielding
Residual drift > 0.2%
Repair of Plates Only V
D50/50
V50/50
Plate yielding
No Repair
Vwind
Connection decompression D

10. Prototype Building Designs
Based on 3- and 9-story SAC buildings in LA
Vary number of R-SPSW bays in building
2 design types:
Plates designed for V50/50
Plates designed for V10/50/R

11. Analytical Model Nonlinear model in OpenSees
SPSW modeled using strip method:
Tension-only strips with pinched hysteresis
Strips oriented in direction of tension field

12. Analytical Model (cont.)
PT connection model:
Compression-only springs at HBE flanges
Rocking about HBE flanges
Shear transfer
Diagonal springs
PT tendons
Truss elements with initial stress (Steel02)
HBE
VBE
Rigid offsets
Physical Model
Analytical Model
Compression-only springs at HBE flanges
Diagonal springs to transfer shear

13. Dynamic Analyses
Each model subjected to 60 LA SAC ground motions representing 3 seismic hazard levels
50% in 50 year
10% in 50 year
2% in 50 year
Used OpenSeesMP to run ground motions in parallel on TeraGrid machines
Processor = 0
Processor = 1
R-SPSW model
Processor = n-1

14. Using TeraGrid Batch submission script OpenSeesMP .tcl scripts
#!/bin/bash
#$ -V
#$ -cwd
#$ -N jobName
#$ -o $JOB_NAME.o$JOB_ID
#$ -e $JOB_NAME.err$JOB_ID
#$ -pe 16way 64
#$ -q long
#$ -l h_rt=48:00:00
#$ -M
#$ -m be
set –x
ibrun $HOME/OpenSeesMP $WORK/OSmodel.tcl
OpenSeesMP .tcl scripts
Ground acceleration records
Abe
Ranger

15. Run all models and ground motions simultaneously using OpenSeesMP
Using TeraGrid
Run all models and ground motions simultaneously using OpenSeesMP
Processor = 0
Processor = 1
Abe
R-SPSW model
Processor = n-1
Ranger

16. All results in the time it takes to run one ground motion.
Using TeraGrid
All results in the time it takes to run one ground motion.
OpenSees recorder & output files
Abe
Ranger

17. Response History Results
Example of Response during 2% in 50 year EQ
System Response
Connection Response

18. Response History Results
Statistical results from all 60 ground motions
Performance Objectives:
No plate repair (Story drift < 0.5%) in 50/50
(this example designed using V10/50/R; plates not explicitly designed to remain elastic)
Recentering (Residual Drift < 0.2%) in 10/50
Story drift < 2.0% in 10/50 (represents DBE)
Limited PT, HBE, and VBE yielding in 2/50
All performance objectives met !!!

19. Comparing Designs R-SPSW designed using V50/50
R-SPSW designed using V10/50/R
Plates designed using reduced “DBE” forces
R-SPSW designed using V50/50
Plates designed to remain elastic in 50% in 50 year EQ
Larger plate thicknesses & frame members
Improved response
Recentering at all hazard levels
Smaller peak drifts

20. Conclusions Preliminary design procedure developed for R-SPSW
Dynamic analyses show R-SPSW can meet proposed performance objectives
including recentering in 10% in 50 year EQ
Highly nonlinear model  significant computational effort
Use of TeraGrid resources reduced computational time by more than 90%
Experimental studies on R-SPSW currently taking place

21. Thank You