Seismic performance index of long-span concrete filled steel tube arch bridges
XIA Xiushen;DU Qian;DAI Shengyong;School of Civil Engineering, Lanzhou Jiaotong University;China Railway Eryuan Engineering Group Co.,Ltd.;
The test results of concrete filled steel tubular columns with a high axial compression ratio are of great significance to the CFST arch ribs. In order to ascertain the seismic performance index of the long span concrete filled steel tubular arch bridge,the failure process and ductility of the concrete filled steel tubular members with an high axial compression ratio are investigated. The failure behavior is divided into 3 stages: minor damage, limited damage and severe damage, when bending moment is used as the performance index. With numerical analyses on the performance of the concrete filled steel tube sections, the failure mechanism of concrete filled steel tubular members with high axial compression ratio is examined. The results show that the concrete-filled steel tube members with an high axial compression ratio have certain ductility. The equivalent yield moment is proposed as the seismic performance index. Limited damage seismic design of concrete filled steel tubular arch bridges can be performed by the utilization of the ductility to some extent. The performance states and parameters of the section associated with limited damage are also given. Research results make up for the deficiencies of codes in this aspect. It can be used as a reference for seismic design of long-span concrete filled steel tubular arch bridges in the high seismic intensity zone.