Hybrid simulation evaluation of the suspended zipper braced frame

1
Hybrid simulation evaluation of the suspended
zipper braced frame
Tony Yang Post-doctoral scholar University of
California, Berkeley
Acknowledgements Georgia Institute of
Technology, University at Buffalo, University of
Colorado, Boulder, Florida AM University
Andreas Schellenberg, Bozidar Stojadinovic, Jack
Moehle
2
Inverted-V braced frame
3
Suspended zipper braced frame
4
Shaking table test
UB
5
Quasi-static test
Analytical simulation
Experimental testing
GT
6
Hybrid simulation test

• Advantages
• Numerical hard to model.
• New systems.
• Economical.
• Test structure to extreme states.
• Collapse.
• Geographically distributed tests.
• Share resources.
• Larger and complex structures.

UCB and CUB
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
1/3 - scale
9
Instrumentation
10
Instrumentation
11
Instrumentation
12
Equations of motion

• Dynamic Loading
• Seismic
• Wind
• Blast/Impact
• Wave
• Traffic

analytical model of structural energy
dissipation and inertia
physical model of structural resistance
13
Integration algorithm

• Newmark average acceleration integration method
• No added numerical damping and
  unconditionally stable.
• Form equilibrium equations at next time step

14
Experimental testing architecture
Physical specimen(s)
Finite element model
Simulation PC
Random time interval
Dsp
Force
Force
Dsp

• Model complexity.
• Processor speed.
• Communication delay.

Real time PC
Test PC
Force
Fixed time interval (_at_ 1024 Hz)
Dsp
P-C program
Servo-control program
15
Transformation of displacement dof
16
Transformation of force dof
Measured forces
Feedback forces to finite element model
Equation 3
17
Movie 100 Kobe Earthquake
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Out-of-plane buckling of the braces
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Out-of-plane buckling of the gusset plate
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Hysteric responses of the braces
3rd story left brace
3rd story right brace
50
50
0
0
-50
-50
-0.5
0
0.5
-0.5
0
0.5
2nd story left brace
2nd story right brace
50
50
Brace axial forces kips
0
0
-50
-50
-0.5
0
0.5
-0.5
0
0.5
1st story left brace
1st story right brace
50
50
0
0
-50
-50
-0.5
0
0.5
-0.5
0
0.5
Brace axial deformations in.
21
Hysteric responses of the zipper columns
3rd story zipper column
20
10
Axial force kips
0
-10
-20
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
2nd story zipper column
20
10
Axial force kips
0
-10
-20
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
Axial deformations in.
22
Analytical verification roof drift ratio
0.8
0.6
0.4
0.2
Roof drift ratio
0
-0.2
-0.4
-0.6
-0.8

0
5
10
15
Time sec
23
Analytical verification brace axial forces
3rd story left brace
3rd story right brace
50
50
0
0
-50
-50


0
5
10
15
0
5
10
15
2nd story left brace
2nd story right brace
50
50
Brace axial forces kips
0
0
-50
-50
0
5
10
15
0
5
10
15
1st story left brace
1st story right brace
50
50
0
0
-50
-50


15
0
5
10
0
5
10
15
Time sec
Time sec
24
Analytical verification - ZC axial forces
3rd story zipper column
20
10
Axial forces kips
0
-10
-20
0
5
10
15
2nd story zipper column
20
10
Axial forces kips
0
-10
-20

0
5
10
15
Time sec
25
Movie 200 Kobe Earthquake
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Out-of-plane buckling of the braces
27
Geographically distributed test
University of California, Berkeley
University of Colorado, Boulder
28
Testing architecture (distributed test)
Real time PC
UC Berkeley
Test PC
Simulation PC
Internet
Real time PC
Simulation PC
Test PC
CU Boulder
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Input ground motions Kobe (80 - 100)
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Hysteric responses of the braces
3rd story left brace
3rd story right brace
50
50
0
0
-50
-50
-1
-0.5
0
0.5
1
-1
-0.5
0
0.5
1
2nd story left brace
2nd story right brace
50
50
Brace axial forces kips
0
0
-50
-50
-1
-0.5
0
0.5
1
-1
-0.5
0
0.5
1
1st story left brace
1st story right brace
50
50
0
0
-50
-50
-1
-0.5
0
0.5
1
-1
-0.5
0
0.5
1
Brace axial deformation in.
31
Hysteric responses of the zipper columns
3rd story zipper column
50
Axial Force kips
0
-50
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
2nd story zipper column
50
Axial Force kips
0
-50
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
Axial deformation in.
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Summary

• Conducted 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.

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Conclusions

• 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.

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Application of hybrid simulation test

• Can be used to test multiple sub-assemblies.
• Larger and more complex structural system.
• More extreme loading.
• Can test the structure to extreme states

35
Question?
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.

• Resource
• http//peer.berkeley.edu/yang/NEESZipper/