STUDY ON ASEISMIC RELIABILITY OF ISOLATED STRUCTURES BASED ON PROBABILITY STATISTICS METHOD

Probability statistics method is used to investigate the aseismic reliability of isolated structures. For two existing isolated buildings. The finite element models were built and dynamic responses were calculated by time history analysis, including the relative story acceleration, story drift, shear strain and compressive stress of rubber isolators. The mechanical properties of rubber isolators were gathered by experiment and numerical simulation. Structures dynamic responses and isolators mechanical properties are proved to follow a lognormal distribution by a hypothesis test, and two probability characteristic parameters are calculated by the maximum likelihood estimation. With the combination of given failure modes and performance functions of resistances and responses, the aseismic reliability of isolated structures is investigated by a second moments method. It shows that:if isolated structures conform to the code for aseismic design of building, and horizontal seismic effects of superstructures reduce 60% to 70% compared with non-isolated structures, it is possible to fail to reach the demand "repairable under rare ground earthquake, not collapsed under very rare ground earthquake". Thusly, Code for aseismic design of seismic isolated buildings on editing proposes a higher request for isolated buildings.