强震作用下RC延性框架的简化计算

提出了一种RC延性框架抗震设计方法,选取合理的倒塌机构并用虚功原理将其转化为等效的单自由度系统,针对选取的倒塌机构、设防烈度及场地条件计算刚塑性反应谱并据此计算结构的动力需求。以五层和九层RC框架为算例并与弹塑性时程分析比较,研究表明该方法计算简单,精度可靠,可以满足强烈地震作用下RC延性框架抗震设计要求。

A simplified method for computing RC ductile frame under strong earthquake

Under strong earthquake the reinforced concrete (RC) ductile frame usually undergoes large plastic deformation.Most of kinetic energy rising from the earthquake is dissipated through plastic deformation.A little part is converted into elastic deformation energy.In view of this mechanism of energy transformation a new seismic design procedure for RC ductile frame is proposed in this paper.The design proceeds in two steps.The first step is to select a suitable collapse mechanism and then to transform it into a single degree-of-freedom system.The second one is to calculate the rigid-plastic spectrum according to the selected collapse mechanism,seismic fortification intensity and site class and to determine the seismic requirement.To illustrate the effectiveness,the method is applied to two example structures.One is a five-storey and the other is a nine-storey RC frame design.The results obtained are in good agreement with the ones by the non-linear time-history analysis.It is shown that the method proposed in this paper has advantages of clear notion,simple calculation and reliable accuracy.It can be used in seismic design for reinforced concrete structures.