Analysis On Lateral-Torsional Coupled Seismic Response Of Base-Isolated Eccentric Structures

During the long-term persistent fight with earthquake disaster, the isolation technology gradually becomes a new thinking, which decreases the seismic responses by changing the dynamic parameter of structure, and shows obvious isolation effects and possesses significant social, technique improvement and economic advantages.At present, the structure is usually simplified as single particle system or multitude particle system when designing the base-isolated structure. The assumption of the calculation is that the structure performs horizontal displacement and no torsional displacement. Following the more extensive application of the base-isolation technology and the diversification of the construction style, the structure performs coupling torsional response besides horizontal movement under earthquake action because the quality center does not coincide with the stiffness center, so study about seismic behaviors of base-isolated eccentric structure is important whether theoretic or practical.Based on the research on restoring force model of isolation systems and the analysis on the nonlinear seismic response of base-isolated structures, according to the mechanical performance of isolation systems, a bilateral coupled differential hysteretic model for lead rubber bearings are used on the basis of the present research. The model of series-wound rigid body system is adopted as the dynamic analysis model for base-isolated eccentric structures, the dynamical equation is established, time-history analysis is conducted by Runge-Kutta method. The analysis on lateral-torsional coupled seismic response of base-isolated eccentric structure and base-fixed structure is carried out, first a comparison on displacement, acceleration and storey displacement maximum between the two kinds of structures was made,then the changes in seismic response through regulating parameter of the superstructure and the isolation bearing are discussed. By means of analysis, some beneficial conclusions are proposed as an exploration for restraining the lateral-torsional coupled seismic response of base-isolated eccentric structure.