设计性能目标下RC框架结构抗倒塌能力研究

针对小震丙类、小震乙类、中震不屈服和中震弹性4个性能目标，采用增量动力时程分析方法（IDA）对钢筋混凝土框架结构的抗倒塌能力进行了分析。以小震丙类建筑为基准，研究结果表明：抗震措施和地震作用是影响结构抗震性能的重要因素；严格按照抗震规范设计的框架结构，具有较高的安全储备，基本上能够达到“大震不倒”的性能目标；6度设防时，按乙类建筑提高抗震措施或按中震性能目标提高设计地震作用，对结构的抗倒塌能力影响不大；7度设防时，按中震性能目标设计能显著提高结构的抗倒塌能力；8度设防时，提高抗震措施等级和提高设计地震作用都能够大幅提高结构的抗倒塌能力，尤其按中震设计的钢筋混凝土框架结构能够抵御加速度峰值1000gal以上的地震作用。

Study on seismic performance of RC frame structure under four performance objectives

The seismic resistance capability of RC frame structure was studied with incremental dynamic analysis(IDA) method in terms of the 4 performance objectives(frequent seismic design of class C,frequent seismic design of class B,non-yielding design under moderate earthquake and elastic design under moderate earthquake).Taking frequent seismic design of class C as basis,results of IDA analysis indicate that both seismic measures and seismic design force are very important influencing factors on seismic performance.The RC frame structures that are designed strictly conforming to the Chinese seismic design code have enough safety margins and the performance level of ’non-collapse under rare earthquake’ can be reached.When the fortification intensity is 6,improving seismic measures for frequent seismic design of class C or increasing seismic design force for moderate seismic design has little influence on seismic performance.When the fortification intensity is 7,the collapse resistance capability of RC structures designed under moderate seismic force can be improved obviously.When the fortification intensity is 8,both improving seismic measures and increasing seismic design force can significantly raise the seismic resistance capability of RC frame structure.Especially,designed under moderate earthquake,the RC frame structure can withstand PGA of 1 000 gal without collapse.