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NEES@Illinois: Small-scale Hybrid Simulation

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Hybrid simulation of a four-span curved bridge was conducted under biaxial seismic excitation using the MUST-SIM facility at NEES@Illinois. This hybrid test is a part of the Combined Actions on Bridge Earthquake Research (CABER) project, officially titled NEES-SG: Seismic Simulation and Design of Bridge Columns under combined Actions, and Implications on System Responses, sponsored by NSF through NEHRP Grant No. NEESR-SG-0530737. The objective of this hybrid test is to investigate the level of combined actions observed in bridge columns arising from spatially-complex system geometries subjected to multi-directional earthquake ground motions, as well as to understand the impact of these combined actions on bridge column performance and overall system response. With the numerical/physical simulation technology, three piers in the curved bridge were experimentally evaluated using Loading and Boundary Condition Boxes (LBCBs), while a numerical model of the remaining substructures (deck and abutments) was concurrently simulated. In this test, a high-precision positioning control scheme was developed to compensate for the flexibility of the support structure of the LBCBs. Extensive traditional and advanced non-contact sensors were used to monitor local and global structural behavior of the bridge piers. Utilizing a post-processing toolbox developed in-house, the detailed performance of bridge piers were derived and represented graphically. In this investigation, the hybrid simulation of this curved bridge was successfully conducted, from which numerous insights were obtained regarding the response of the four-span curved bridge structure. More details are available at

Small-scale to large-scale hybrid test: A detailed comparison of two hybrid tests conducted at different scales is provided in this video. Prior to conducting the large-scale CABER test, a hybrid simulation employing three 1/20th-scale bridge piers is performed to validate the hybrid simulation framework developed and used in the MUST-SIM facility. These preliminary tests are implemented to verify preparedness for the final large-scale hybrid test in terms of controls and test setup. Additionally, they provide researchers with a general understanding of the levels of combined actions to expect in bridge columns subjected to complex earthquake loading. This small scale assessment is used to inform and develop loading protocols and instrumentation plans in the following large scale hybrid test. Comparable results shown in the video indicate that small-scale hybrid testing provides informative results for use in preparing for and implementing large-scale hybrid simulations.

Credits and References

David H. Sanders, Pedro F. Silva, Chia-Ming Chang, Thomas, M. Frankie, Daniel A. Kuchma, Billie F. Spencer, Jr., and Amr S. Elnashai

Principal Investigator: David Sanders, University of Nevada, Reno

Investigator: Pedro Silva, George Washington University

Investigator: Daniel Kuchma, University of Illinois

Investigator: Ashraf Ayoub, University of Houston

Investigator: Abdeldjelil Belarbi, University of Houston

Investigator: Shirley Dyke, Purdue University

Investigator Amr Elnashai, University of Illinois

Investigator: Jian Zhang, University of California, Los Angeles

Director of MUST-SIM Facility: Billie Spencer, Jr., University of Illinois

Postdoctoral Researcher: Chia-Ming Chang, University of Illinois

Ph.D. Candidate: Thomas Frankie, University of Illinois

Cite this work

Researchers should cite this work as follows:

  • Chia-Ming Chang; Thomas Frankie; Michael Allan Johnson (2013), "NEES@Illinois: Small-scale Hybrid Simulation,"

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