This presentation covers the use of ANSYS to develop a new system of seismic lateral load resisting system for tall buildings. Steel shear walls can be a safe economic model to resist seismic forces in skyscraper design. However, current steel shear walls can buckle under relatively small lateral forces. The innovative buckling restrained steel shear walls under development, using ANSYS to reduce the cost of construction and increase the capacity of the wall by preventing wall buckling.

1. 1 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
Buckling Restrained Steel Shear
Walls for Seismic Protection
X. Qian and A. Astaneh-Asl
University of California, Berkeley

2. 2 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
Earthquakes create horizontal
inertia forces in buildings
 Horizontal inertia forces need to be
resisted by lateral load resisting
system
Lateral load resisting systems also
resist lateral loads due to wind
Seismic Protection of Tall Buildings

3. 3 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
Lateral Load Resisting Systems:
Moment Frames Braced Frames Shear Walls

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Lateral Load Resisting Systems:
Braced Frames
http://www.aviewoncities.com/
Moment Frames
www.toptenepic.com/
Shear Walls
www.timgriffith.com

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What is a Steel Shear Wall?
The main role of a steel shear
wall is to collect the lateral
forces of earthquakes or
winds in a building and
transfer those forces, in
shear, to the foundations
and the ground.
• Steel shear walls studied here
are steel plates welded to
beams and columns in a
building.
www.timgriffith.com

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6
Stiffened Steel Plate
Used in Japan
Unstiffened Steel Plate
Used in U.S.A
Steel plate shear walls are either “unstiffened” or “stiffened” . Stiffened steel shear walls
have horizontal and vertical stiffeners to divide the plate to smaller panels that will not
buckle until the entire plate has yielded in shear.
Types of Steel Shear Wall Panels:

7. 7 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
30-story Steel Shear Wall Building in Kobe Japan
After the 1995 Kobe Earthquake
1996
After the 1996 retrofit
Steel Shear
Wall Building

8. 8 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
Seismic Studies of an Innovative Steel
Shear Wall System
Objective: To develop an innovative steel plate
shear wall system for wind and seismic lateral
force resisting
Performance objective: limit the failure to first
buckling under frequent earthquakes and
design wind load, while allowing yielding of the
shear wall system under maximum considered
earthquake.

9. 9 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
RESEARCH METHODOLOGY
 First Stage  Current Focus
 Conduct literature survey
 Validate computational tools (ANSYS)
 Establish seismic demand on the innovative system (ANSYS)
 Optimize the system (ANSYS)
 Develop tentative seismic design recommendations based on analysis
 Apply the design guidelines to design steel shear walls for low-, mid-and
high-rise buildings and possibly bridge applications
 Conduct time history analysis of structures subjected to ground
motions as well as wind effects using ANSYS and refine the design
procedure
 Design two specimens representing traditional and innovative shear
walls and perform pre-test analysis of behavior under cyclic loading up
to fracture failure using ANSYS
 Fabricate and conduct cyclic tests of two 1/2 scale specimens that are
designed using the proposed design procedures and based on their
behavior further refine and finalize the design procedures.

10. 10 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
ANSYS ANALYSIS PLANS
• Validate FEA simulation – Use ANSYS to model
existing test specimens and loading and compare its
prediction of behavior of specimens to actual test
results. (this presentation)
• Case Study Model: Jinta Tower in Tianjing, China
• Designed by S.O.M.
• Test by Tsinghua University
• Generic Low-, mid-, and high-rise structures using
proposed innovative “buckling restrained” steel
shear walls

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VERIFICATION OF ANALYSIS SOFTWARE
AND MODELING ISSUES
Tested specimen used in simulation:
from: Lubell, 1997)

12. 12 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
VERIFICATION OF ANALYSIS SOFTWARE AND
MODELING ISSUES
Simulation of actual behavior of tested steel shear wall
specimens using ANSYS:
(Photo: Curtsey of C. Ventura)) (Curves from: Lubell, 1997)

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CASE STUDY 1: 10 Scale Test Specimen

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Mesh
The ANSYS
shell181 element
is used for infill
plates and
boundary
elements. Mapped
mesh is used .

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Boundary Conditions
Top Beams
and
Loading
Actuators

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Boundary Conditions
Bottom
Beam
Support

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Results
Comparison between ANSYS Simulation and Test Results

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Results
Comparison between ANSYS Simulation and Test Results

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Results
The Problem with Plate Buckling and Column Bending

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Buckling of Plate and Bending of Columns

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Innovative Buckling Restraining Stiffeners

22. 22 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
ANSYS ANALYSIS PLANS
• Validate FEA simulation – Use ANSYS to model
existing test specimens and loading and compare its
prediction of behavior of specimens to actual test
results. (this presentation)
• Case Study Model: Jinta Tower in Tianjing, China
• Designed by S.O.M.
• Test by Tsinghua University
• Generic Low-, mid-, and high-rise structures using
proposed innovative “buckling restrained” steel
shear walls

23. 23 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
ANSYS ANALYSIS PLANS
• Case Study Model: Jinta Tower in Tianjing, China
• Designed by S.O.M.
• Test by Tsinghua University
www.timgriffith.com

24. 24 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
Test details
Reference: Nie et al(2013)

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Test details cont.
SPSW1
(Not Buckling Restrained)
Total lateral load vs overall drift
Inter-story lateral load vs inter-story drift
SPSW2
(Buckling Restrained)

26. 26 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
• Using ANSYS we were able to simulate buckling behavior of
two test specimens of steel shear walls.
• Also, using ANSYS, we simulated behavior of steel shear walls
with vertical stiffeners acting as buckling restraining
elements.
• This was our use of ANSYS and now we are embarking on
simulating fracture crack initiation and propagation as well
as cyclic yielding and buckling behavior simulation using
ANSYS.
• The goal is to use ANSYS in developing an innovative buckling
restrained steel shear wall for buildings to resist wind and
seismic lateral forces.
Concluding Remarks

27. 27 © 2014 ANSYS, Inc. May 19, 2014 ANSYS Confidential
We acknowledge and appreciate very valuable
support and technical assistance received from
Casey Heydari, Chris Cowan, and Cassandra Casteel
, all of Ozen Engineering Inc.
Also, we appreciate the time and professional care
that Ian Lockley and Ming Yao Ding, both of ANSYS
Inc. spent with us in guiding us in our preparation
of this presentation.
Acknowledgements