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Hybrid simulation evaluation of the suspended zipper braced frame

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 A&M University

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Hybrid simulation evaluation of the suspended zipper braced frame

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  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 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. 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 (@ 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

  18. Out-of-plane buckling of the braces

  19. Out-of-plane buckling of the gusset plate

  20. Hysteric responses of the braces 3rd story right brace 3rd story left 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. Experiment Analytical 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. Experiment Analytical 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. Experiment Experiment Analytical Analytical 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

  26. 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 Test PC UC Berkeley Simulation PC Internet Real time PC Test PC Simulation PC CU Boulder

  29. 1 0.8 0.6 0.4 0.2 Ground accelerations [g] 0 -0.2 -0.4 -0.6 -0.8 0 5 10 15 20 25 Time [sec] Input ground motions – Kobe (80% - 100%)

  30. 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.]

  32. 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.

  33. 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.

  34. 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/

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