Response Analysis Of Parallel Composite Isolation

Isolation technology was commonly applied in reconstruction of Wenchuan Earthquake;isolation devices are mainly inclusive of sliding isolation bearings, rubber bearings and dampers; diverse types of isolation devices are effectively combined to develop individual advantages, and to play excellent isolation effect. Currently, composite isolation technology is increasingly widespread, but there is not much study on its theory.The seismic response of parallel composite isolated structures are studied in this paper, and laminated rubber bearings(LRB)and sliding isolation bearings are employed to form isolation layer."Friction Isolator"and"Rubber Isolator elements"in SAP2000 are used to simulate laminated rubber bearings and sliding isolation bearings, 6 layer frame structures of the isolation model are established, and conclusions are obtained from comparing seismic response of composite isolated structure and corresponsive seismic structure, the seismic response of upper structure can be effectively reduced, and isolation effect is obvious, when the composite isolation technique is used, moreover, the torsion reaction of upper structure can be also greatly reduced, when the superstructure eccentricity is existent. In the composite isolated structures, effect of composite isolation is diverse for different installation of the couple of isolation bearings. Overall, the chief factors affecting effect of composite isolation are as followings: the selection of friction coefficient for sliding isolation bearings, number and models (equivalent rigidity) of laminated rubber bearings. In this paper, the friction coefficient of sliding isolation bearings ranges from 0.02 to 0.22, and models of laminated rubber bearings are GZY200-40,GZY400-80,GZY600-120 .By the study on natural period, displacement of isolation layer, and peak value of storey torsion of isolated structure, etc. it is concluded that natural vibration period of composite isolation structure increases as friction coefficient for sliding isolation bearings, maximum drift of isolation layer could be decreased by laminated rubber bearings, and laminated rubber bearings also plays individual energy dissipation characteristic under earthquake; isolation effect is mainly determined by friction coefficient for sliding isolation bearings, when there are less laminated rubber bearings for composite isolation, while the more laminated rubber bearings, the stronger torsion reaction of upper structure is for irregular structure.