Analysis On Multi-Dimensional And Lateral-Torsional Coupled Seismic Response Of Base-Isolated Structures

In the recent thirty years, due to their favorable aseismic performance both in laboratory and in realty, base-isolated structures have attracted extensive attention in both academic field and engineering field. Base-isolation technique has been considered as a viable alternative aseismic method, not only for designing of new structures, but also for rehabilitating of deficient buildings and protecting of historical buildings. The application and development of base-isolation technique is closely bound up with the progress of the research on the mechanical performance of isolation systems and on the analysis theory and calculation method of the seismic response of base-isolated structures. However, in the present research, many objective factors which influences the seismic response of base-isolated structures have been neglected because of adoption of simple calculation model and supposition. In order to develop and consummate the analysis theory and calculation method of base-isolated structures, based on the research on restoring force model of isolation systems and the analysis on the nonlinear seismic response of base-isolated structures, the analysis on multi-dimensional and lateral-torsional coupled seismic response of base-isolated structures is developed in this paper.According to the mechanical performance of isolation systems, detailed analysis and improvement of the present research, an unilateral and a bilateral coupled visco-elastic hysteretic model for rubber bearings, an unilateral and a bilateral coupled visco-elasto-plastic differential hysteretic model for lead rubber bearings, an unilateral and a bilateral coupled modified visco-plastic differential hysteretic model for sliding friction bearings are proposed. The models are proved to be concise and efficient compared with the tests results.The spatial member-story model is adopted as the dynamic analysis model for base-isolated structures by considering the isolation device as a special element, the dynamical equation isestablished, time-history analysis is conducted by step-by-step integration and iteration methods, and program of dynamic analysis on base-isolated structures (DABIS) which can be used for analysis on multi-dimensional and lateral-torsional coupled seismic response of base-isolated structures is worked out.The analysis on unilateral, bilateral and lateral-torsional coupled seismic response of base-isolated structures with lead rubber bearings is carried out. The maximal displacement of the bearings is studied. The influence on lateral-torsional coupled seismic response of base-isolated structures due to the excentricity and uncoupled period ratio of the superstructure, and the excentricity of the isolation system is investigated. The control of lateral-torsional coupled seismic response of structures is discussed.The analysis on unilateral, bilateral and lateral-torsional coupled seismic response of base-isolated structures with sliding friction bearings is carried out. The influence on lateral-torsional coupled seismic response of base-isolated structures due to the excentricity and the uncoupled period ratio of the superstructure is investigated, and the control of lateral-torsional coupled seismic response of structures is discussed.The analysis on unilateral, bilateral and lateral-torsional coupled seismic response of base-isolated structures with combined isolation systems is carried out, and the control of lateral-torsional coupled seismic response of structures is discussed.The energy analysis on base-isolated structures is conducted by energy method. The influence on the total input earthquake energy owing to the frequency, intensity and lasting-time of earthquake and so on is studied. The dispassion of the total input earthquake energy is also investigated.Through the study on the restoring-force model of isolation systems and on the nonlinear seismic response of base-isolated structures, the program of dynamic analysis of base-isolated structures (DABIS) is worked out. Detailed analysis on...