Large-Scale Cyclic and Hybrid Simulation Testing and Development of a Controlled-Rocking Steel Building System with Replaceable Fuses

摘要

Current U.S. building codes and earthquake engineering practice utilize inelasticity in the seismicforce resisting system to dissipate seismic energy and protect against collapse. Inelasticity inconventional structures can lead to structural damage distributed throughout the building andpermanent drifts after the earthquake motion ceases which can make the structure difficult if notfinancially unreasonable to repair. A controlled rocking system has been developed that virtuallyeliminates residual drifts and concentrates the majority of structural damage in replaceable fuseelements. Portions of the development related to but not contained in this report include fusetesting, fuse analysis, large-scale shake table testing, development of a displacement based designprocedure, and collapse modeling.The controlled rocking system is investigated and developed through analytical,computational, and experimental means. A large-scale experimental program was conductedincluding quasi-static cyclic and hybrid simulation tests. Nine specimens were testedrepresenting three-story frames at approximately half scale. These experiments validated theperformance of the system, demonstrated system response when subjected to simulated groundmotions, allowed the investigation of detailing and construction methods, provided informationon frame member forces, and provided data to confirm and calibrate computational models.Computational models were developed based on the experimental behavior and twocomputational studies were conducted. A single degree-of-freedom study consisting of over25,000 analyses was performed to investigate system proportioning including defining theamount of restoring force that is necessary to provide reliable self-centering in the presence ofambient building resistance. A multi-degree-of-freedom study consisting of approximately 1500analyses was performed to investigate the application of the controlled rocking system indifferent configurations. This study was also used to investigate the probabilities of reachinglimit states for earthquake events with varying recurrence period.The experimental and computational studies described in this report demonstrate that thecontrolled rocking system for steel-framed buildings can satisfy the performance goals ofvirtually eliminating residual drift and concentrating structural damage in replaceable fuses evenduring large earthquakes. The results of all phases of this work were synthesized into designrecommendations which summarize the practical application of this system to building structures.