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Hybrid simulation evaluation of the suspended zipper braced frame
Tony YangTony YangPost-doctoral scholarUniversity of California, Berkeley
Acknowledgements:Georgia Institute of Technology, University at Buffalo,University of Colorado, Boulder, Florida A&M University Andreas Schellenberg, Bozidar Stojadinovic, Jack Moehle
2
Inverted-V braced frame
3
Suspended zipper braced frame
4
Shaking table test
UB
5
Experimental testing
Analytical simulation
Quasi-static test
GT
6
Hybrid simulation test
UCB and CUB
Advantages:
• Numerical hard to model.
• New systems.
Economical.
• Test structure to extreme states.
Collapse.
• Geographically distributed tests.
Share resources.
Larger and complex structures.
7
Scope of the hybrid simulation test
Utilize OpenSees to simulate the analytical elements and use the time-step integration algorithms to solve the equations of motion.
Geometry and material nonlinearities are accounted in both analytical and experimental elements.
Develop an experimental testing architecture (OpenFresco) to communicate between OpenSees and experimental setup.
8
Test setup
- scale
9
Instrumentation
10
Instrumentation
11
Instrumentation
12
physical model of structural resistance
analytical model of structural energy dissipationand inertia
Dynamic Loading Seismic Wind Blast/Impact Wave Traffic
Equations of motion
rP ,n n n n nM u Cu u u P
13
Newmark average acceleration integration method
No added numerical damping and unconditionally stable.
Form equilibrium equations at next time step
21 1 / 4n n n n nu u hu h u u
1 1 / 2n n n nu u h u u
Integration algorithm
1 1 r 1 1 1P ,n n n n nM u Cu u u P
2
r 1
4 4 2
P , , , 0
n n n n n
n n n n
F u M u u u u C u u uh h h
u u u u P
14
Finite element model Simulation PC
Real time PC
P-C program
Random time interval• Model complexity.
• Processor speed.• Communication delay.
Dsp
Dsp
Test PC
Servo-control program
Physical specimen(s)
Fixed time interval (@ 1024 Hz)
DspForce
Force
Force
Experimental testing architecture
15
Transformation of displacement dof
16
Equation 3
Transformation of force dof
Feedback forces to finite element modelMeasured forces
17
Movie – 100% Kobe Earthquake
18
Out-of-plane buckling of the braces
19
Out-of-plane buckling of the gusset plate
20
Hysteric responses of the braces
Brace axial deformations [in.]
-0.5 0 0.5-50
0
503rd story left brace
-0.5 0 0.5-50
0
50
-0.5 0 0.5-50
0
50
Bra
ce a
xial
forc
es [k
ips]
-0.5 0 0.5-50
0
50
-0.5 0 0.5-50
0
501st story left brace
-0.5 0 0.5-50
0
501st story right brace
3rd story right brace
2nd story left brace 2nd story right brace
21
Hysteric responses of the zipper columns
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-20
-10
0
10
20
3rd story zipper column
Axi
al fo
rce
[kip
s]
-0.06 -0.04 -0.02 0 0.02 0.04 0.06
-20
-10
0
10
20
2nd story zipper column
Axi
al fo
rce
[kip
s]
Axial deformations [in.]
22
Analytical verification – roof drift ratio
0 5 10 15-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Time [sec]
Roo
f drif
t rat
io [%
]
ExperimentAnalytical
23
Analytical verification – brace axial forces
0 5 10 15-50
0
50
3rd story left brace
0 5 10 15-50
0
50
3rd story right brace
0 5 10 15-50
0
502nd story left brace
Bra
ce a
xial
forc
es [k
ips]
0 5 10 15-50
0
502nd story right brace
0 5 10 15-50
0
50
1st story left brace
Time [sec] 0 5 10 15
-50
0
50
1st story right brace
Time [sec]
ExperimentAnalytical
24
Analytical verification - ZC axial forces
0 5 10 15
-20
-10
0
10
20
3rd story zipper column
Axi
al fo
rces
[kip
s]
0 5 10 15
-20
-10
0
10
20
2nd story zipper column
Time [sec]
Axi
al fo
rces
[kip
s]
ExperimentAnalytical
ExperimentAnalytical
25
Movie – 200% Kobe Earthquake
26
Out-of-plane buckling of the braces
27
Geographically distributed test
University of California, Berkeley
University of Colorado, Boulder
28
UC Berkeley
CU Boulder
Internet
Testing architecture (distributed test)
Simulation PC Real time PC Test PC
Simulation PC Real time PC Test PC
29
Input ground motions – Kobe (80% - 100%)
0 5 10 15 20 25-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Time [sec]
Gro
und
acce
lera
tions
[g]
30
Hysteric responses of the braces
-1 -0.5 0 0.5 1-50
0
503rd story left brace
-1 -0.5 0 0.5 1-50
0
503rd story right brace
-1 -0.5 0 0.5 1-50
0
502nd story left brace
Bra
ce a
xial
forc
es [k
ips]
-1 -0.5 0 0.5 1-50
0
502nd story right brace
-1 -0.5 0 0.5 1-50
0
501st story left brace
Brace axial deformation [in.]
-1 -0.5 0 0.5 1-50
0
501st story right brace
31
Hysteric responses of the zipper columns
-0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1-50
0
50
3rd story zipper columnA
xial
For
ce [k
ips]
-0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1-50
0
50
2nd story zipper column
Axi
al F
orce
[kip
s]
Axial deformation [in.]
32
SummaryConducted a system evaluation of the suspended zipper braced frame using hybrid simulation tests.Both material and geometry nonlinearities are accounted in the analytical and experimental elements. Results of the hybrid and analytical simulation tests matched well. This shows the testing methodology works for complex structural system such as the suspended zipper braced frame.
33
Behavior of the suspended zipper braced frame Behave as intended. Many redundancies. Braces buckled out of plane. Zipper columns are effective in transferring
unbalanced vertical forces. Beams rotated out of plane, needed to be braced.
Results of the hybrid simulation test First hybrid simulation test to combine complex
analytical and experimental elements. Excellent match between the hybrid and analytical
simulation results. This shows the analytical brace model, solution
algorithm and experimental testing architecture works.
Conclusions
34
Application of hybrid simulation testCan be used to test multiple sub-assemblies.Larger and more complex structural system. More extreme loading.Can test the structure to extreme states
Question?
Resource:http://peer.berkeley.edu/~yang/NEESZipper/
Thank you!
This work was supported in part by the National Science Foundation under a pre-NEES award number CMS-0324629. Any opinions, findings, and conclusions or recommendations expressed in this document are those of the authors and do not necessarily reflect those of the National Science Foundation.