IDA-based Steel-frame Construction Seismic Fragility Analysis Subjected To Near Ground Motion

In China,the distribution of seismic faults is pretty complicated,and the number of earthquake is very large.Many earthquake damage phenomena show that the structure's damage of facing near-fault ground motion is more serious than not-near-fault ground motion.However,there is a lack of quantitative study on the structural seismic fragility facing near-ground motion.In this paper,we choose steel frame structure and use seismic fragility based on IDA(Incremental Dynamic Analysis)to study the damage probability facing near-fault ground motion and not-near-fault ground motion.The main research work and achievements are as follows:(1)Using OpenSees to establish the finite element model of the 6 story steel frame structure,using IDA analysis by 12 near-fault and 12 not-near-fault ground motion vibrations.It is found that the damage measure of model facing near-fault ground motion is much larger than not-near-fault ground motion.(2)Based on the analysis results of IDA curves,carrying out the seismic fragility analysis of the steel frame model.The results show that the model is more vulnerable facing near-fault ground motion.(3)Based on the single variable seismic intensity parameters of IM formation of the vulnerability curve,the multi variable(two or three variables)seismic vulnerability method of seismic intensity parameter form the vulnerability of the 3D surface,the vulnerability of the four-dimensional graphics.(4)In order to reduce the dispersion of vulnerability analysis,it is necessary to distinguish thefield belongs to the near field or the not-near field in the process of seismic vulnerability analysis.(5)The results show that there is some difference between the statistical value and the proposed value,and the statistical value is used as the discrete parameter value in the vulnerability analysis.