Seismic Fragility Analysis Of RC Frame Structure Based On Energy Balance

In the frame structure design,"strong column weak beam" is one of the basic measures to design a ductile frame and increase the energy dissipation capacity of the frame structure.However,in the investigation of earthquake damage,the "strong column weak beam" type failure required by the code is seldom seen.Therefore,in this paper,the "strong column weak beam" yield mechanism is used as the failure mode of reinforced concrete frame structure(RC frame structure),and the energy method is used for its seismic design,based on the consideration of the influence of randomness of ground motion on seismic vulnerability analysis.It conducts vulnerability analysis based on incremental dynamic analysis(IDA method).The main contents and results are as follows:(1)According to the failure mode of RC frame structure,based on the basic principle of energy balance,a seismic design process based on energy method for RC frame structure is proposed.(2)The vulnerability of the RC frame structure at diffierent earthquake levels is established,and the probability of RC frame failure at different levels is predicted.At the same time,the energy response of the RC frame structure under different ground motions is analyzed.With non-linear time history reaction,verify the rationality of this method.(3)On the basis of considering the randomness of ground motion,using the Perform 3D finite element analysis software to perform incremental dynamic analysis(IDA analysis)of the RC frame structure based on the energy method design and the RC frame structure designed to obtain the RC frame structure Earthquake vulnerability curves,failure state probability curves,and structural damage probability matrix.The show that the RC frame structure designed based on the energy method has strong anti-collapse ability and can meet the performance requirements of "small shocks are not bad,moderate shocks can be repaired,large earthquakes do not fall".(4)Analyze and compare the elasto-plastic energy consumption of RC frame structures with two methods and the hingeability of the structure under rare earthquakes.The results show that the seismic design based on the energy method can fully utilize the overall structure of beam members.The advantage of energy is that it is easier to form a plastic hinge and dissipate the energy input by the earthquake,thereby realizing the failure mode of "strong column weak beam".