Nonlinear Seismic Response Analysis Of Base-isolated Structures

In resent thirty years, base-isolated structures have been paid great attention in both academic field and engineering field due to its favorable performance. The base-isolated structures are fairly ordinary in some developed countries, and it is developing rapidly in China. Many scholars have accomplished a lot of theoretical and computational work on the seismic response analysis of base-isolated structure. For this kind of newly emerging structure, it is necessary to make more complete summary and improvement for the computational theory and method of its seismic response analysis, and put forward more valuable suggestions for its design.According to the newly variable stiffness base isolator with one concrete filled steel tubular column, a elasto-plastic biaxial hysteretic model was presented, which can accurately describe the deformation of the bearings and is convenient for application. This hysteretic model can also be used to describe rubber bearing and sliding friction bearing by modifying some parameters. According to the hysteretic model of this base isolator, another elasto-plastic biaxial hysteretic model was presented, which can accurately describe variable stiffness base isolator with two concrete filled steel tubular columns.On the basis of the work described above and HBTA2.0 (High Rise Building Time-history Analysis) program, HBTA2.5 program is completed, which can make nonlinear seismic response analysis for the variable stiffness base isolator with one or two concrete filled steel tubular columns, rubber bearing and sliding friction bearing under multi-directional earthquake. Compared with SAP2000 program, HBTA2.5 is proved to be sufficiently reliable.Depending on HBTA2.5, seismic analysis of one and two columns base-isolated structure was executed. The results proved that HBTA2.5 isreliable. If we choose proper parameters, the seismic response of both base-isolated structures will be reduced apparently. Both isolators have great performance in reducing seismic response with a bright future. On the base of the analysis, some valuable suggestions were made for the choice of parameters of the isolators.Seismic energy analysis of base-isolated structure was executed. The energy analysis shows that both isolators can dissipate the seismic energy efficiently and protect the structure. Finally, some valuable suggestions were made for the further research and design of base-isolated structures.