Dynamic analysis of fiber-reinforced elastomeric isolation structures

This paper presents an analysis of seismically isolated buildings using fiber-reinforced elastomeric structures that are subject to excitations caused by earthquakes. In analyzing the vibrations, the buildings are modeled by lumped mass systems. The fundamental equations of motion are derived for base isolated structures, and the hysteretic and nonlinear- elastic characteristics are included in the numerical calculations. The earthquake waves used as the excitation forces are those that have been recorded during strong earthquake motions in order to examine the dynamic stability of building structures. The seismic (nonlinear) responses of the building are compared for each restoring force type and, as a result, it is shown that the building’s motions are not so large from a seismic design standpoint. Isolating structures are shown to reduce the responses sufficiently allowing the building’s motions to be controlled to within a practical range. By increasing the acceleration of the earthquake, the yielding forces in the concrete and steel frames can be determined, which shows the advantages of performing nonlinear dynamic analysis in such applications. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Gyung-Ju Kang received a B.S., M.S. and Ph.D degrees in Aerospace Engineering from Pusan National Univer-sity, Korea, in 1997, 1999 and 2005, respectively. Dr. Kang’s research interests are in the area of seismic bearing design, base isolation, cold forging, and steel structure. Beom-Soo Kang received a B.S. degree in Mechanical Engineering from Pusan National University, Busan, Korea in 1981. He then went on to receive his M.S. degree in Aerospace Engineering from KAIST (Korea Advanced Institute of Science and Technology) Seoul, Korea, in 1983 and Ph.D. degree in Mechanical Engineering from University of California at Berkeley in 1990. Dr. Kang is currently a Professor at Department of Aero-space Engineering at Pusan National University. He is currently serving as the Director of ILIC (Industrial Liaison Innovation Cluster). Dr. Kang’s re-search interests include flexible forming, unmanned system design, multi-stage deep drawing, and cold forging.