大跨度钢管混凝土拱桥抗震性能指标研究

Seismic performance index of long-span concrete filled steel tube arch bridges

高轴压比钢管混凝土墩柱的试验结果对钢管混凝土拱肋具有较大的借鉴意义。为明确大跨度钢管混凝土拱桥的抗震性能指标,研究了高轴比钢管混凝土构件的破坏过程及延性性能。以弯矩作为性能指标将高轴压比钢管混凝土构件的试验破坏过程分为轻微损伤、有限损伤与严重损伤3个阶段,结合钢管混凝土截面性能状态的数值分析,探讨了高轴压比钢管混凝土构件的破坏机理。结果表明:高轴压比钢管混凝土构件具有一定的可用延性;提出了以计算等效屈服弯矩作为抗震性能指标,适当利用延性和实现钢管混凝土拱桥的有限损伤抗震设计,并给出了与有限损伤相关的截面性能状态及参数。研究成果弥补了规范在此方面的不足,可供高烈度地震区大跨度钢管混凝土拱桥抗震设计时参考。

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.