Research & Development Of Lead Recycle Tire Pads(LRTP) And Its Application Study

China,one of the most earthquake-prone countries in the world,which buildings are rarely designed in accordance with seismic code in villages and small towns.Therefore,those buildings’ seismic capacity is very poor,earthquake is a prominent natural disaster which pose threat to rural residents’ life and property.Base isolation technology can significantly improve seismic capacity of buildings,however,because of high cost,complicated structure and great difficulty in construction,traditional laminated rubber bearings have some difficulties in popularization and application of rural buildings.Furthermore,due to use function of rural buildings and their own structure design is irregular,structure’s mass center and stiffness center are not coincident which leads to their torsional earthquake effect is obvious.In view of Chinese rural buildings in"small earthquake induced damage" or even "small earthquake induced disaster”,in order to improve their seismic capacity,a low cost,simple structure,convenient construction,low maintenance cost of Lead Recycle Tire Pads(LRTP)was researched and developed,and the seismic isolation design method which considering torsional earthquake effect is proposed.The main research work of this paper are as follows:(1)Through vertical and horizontal mechanical behavior testings of LRTP and Recycle Tire Pads(RTP),vertical limit loading capacity,vertical stiffness,ultimate shear capacity,horizontal equivalent stiffness,equivalent damping ratio and other mechanical behavior and failure modes of above both were comparative analysis in detail,mechanical behavior of LRTP was much better than that of RTP can be found,and the former was close to that of common lead rubber bearing(LRB).In addition,LRTP has low cost and environmental protection,so,which is very suitable for used to improve seismic capacity of rural buildings,so as to reduce casualties and economic losses.(2)Based on summary and analysis of domestic and foreign research results which studied on torsion caused by structure eccentricity,traditional seismic isolation scheme that isolation layer’s stiffness center and superstructure’s mass center are coincident is not necessarily able to reduce torsional response of upperstructure and isolation layer is obtained,the seismic isolation design method for multi storied buildings(Take rural masonry buildings in China as example)with structure eccentricity is proposed,and corresponding building structure design is carried out.(3)Based on experimental results of LRTP and the seismic isolation design method which considering structure eccentricity,a typical irregular seismic design of rural buildings in Sichuan Province was taken as research object,SAP2000 finite element model which use equivalent frame method of masonry building without base isolation and use LRTP isolation is established,typical earthquake ground motion under I,II and III sites is selected and seismic time history response analysis is carried out,it is concluded that seismic response of structure can be significantly reduced by using LRTP isolation,and developed LRTP has well isolation performance;At the same time,through seismic time history response analysis,results of isolated model which use the design method and isolated model which use traditional seismic isolation scheme that isolation layer’s stiffness center and superstructure’s mass center are coincident are compared and analyzed,the conclusion is that when eccentricity of isolation layer and eccentricity of superstructure satisfy a certain relationship,torsional response of superstructure and isolation layer is minimum,and the seismic isolation design method which considering structure eccentricity is verified.