Abstract:To achieve consistent collapse risk, risk-targeted ground motion parameters were investigated. First, based on the ArcGIS Engine software, a discrete algorithm was used to analyze the probability of seismic hazard in Xian region. Then, by considering the seismic fragility of the structure, the risk-targeted ground motion parameters of very rare earthquake, maximum considered earthquake, and design basis earthquake for each control point were obtained by risk integral based on the annual exceeding probability curves obtained from seismic hazard analysis and the ground motion decision parameters obtained from existing research results. The risk-targeted ground motion parameters were denoted as PGARV, PGARM, and PGARD, respectively. The relation between the risk coefficient Rc (defined as the ratio of PGARM to the ground motion intensity corresponding to maximum considered earthquake) and K1 (defined as the ratio of PGARV to PGARD) and K2 (defined as the ratio of PGARM to PGARD) were calculated. Finally, based on the parameter effect analysis, the effect of βR (i.e., logarithmic standard deviation of structural fragility) on PGARM, Rc, K1, and K2 was investigated with its value chosen to be 0.5,0.6,0.7,0.8,0.9, and 1.0, respectively. Results show that the collapse probability did not increase with the increase of the ground motion intensity corresponding to very rare earthquake. Parameters PGARM, Rc, K1, and K2 all increased with the increase of βR. The larger βR was, the greater the effect on PGARM and Rc was, while the effect on K1 and K2 remained unchanged with increasing βR. Compared with PGARM and Rc, K1 and K2 were more sensitive to βR, and K1 was the most sensitive to βR among all the parameters. The risk-targeted ground motion parameters obtained in Xian region can provide references for seismic design.