Seismic Isolation Of Long-Span Spatial Structures Using SMA-Rubber Composite Bearing

This thesis presents a study of seismic isolation of long-span spatial structures using SMA-rubber composite bearing. First, the defects of rubber bearings are concluded and accordingly the superelastic hystereresis of SMA is used to design a new type of base to reduce vibration which is named SMA-rubber composite bearing. Then the formula which includes the effects of SMA has been deduced and program for it has been compiled. The program is proved to be an accurate solution of resilience for SMA with different parameter conditions.Second,in this thesis equations for long-span spatial structures with different kinds of bearings under seismic forces have been deduced. Excitation equations of long-span spatial structures with three defferent bases which includes non-seismic isolation bearings,rubber bearings,and SMA-rubber composite bearings have been deduced out.Based on the equations analysis on a long-span lattice shell has been carried out. Results proves that compared with rubber bearings,structures with SMA-rubber composite bearings are more fitful under seismic forces which can reduce both distortion and internal force of the long-span structures.Third,a detailed analysis on a double-layer cylindrical lattice shell has been carred out to investigate the law of SMA-rubber composite bearings under seismic forces under different conditions which includes different seismic forces,different geometry configures of the structure and different initial parameter conditions of SMA silk. And comparisons are made between non-reduction vibration bearings and rubber bearings and SMA-rubber composite bearings. Some valuable conclusions are drawn. Finally, useful results are totally conluded ,mainly focus on the law of seismic reduction which related to the internal forces of different bars of the structure,which shows that long-span structures with SMA-rubber composite beaings can effectively reduce the seismic forces and are prefer to those with rubber bearings, and expectations on the research are proposed.