A new method of determining the collapse capacity and risk of RC structures incorporating near-fault pulse period effect by considering confinement ratio

Collapse capacity is one of the fundamental factors in evaluating collapse risk in the performance-based design engineering field. Calculation of this parameter has been time-consuming during the past decade. This issue has prevented engineers from determining this parameter in a prevalent and practical way. Furthermore, denifing of this value has been found more challenging in a near-source region due to special characteristics of its pulse-like records, which make the collapse capacity more dependent on period ratio, T=T p. In this study, a method was proposed to obtain collapse capacity of Reinforced Concrete (RC) structures considering two main variables affecting the behavior of columns, namely axial load ratio and confinement ratio. The mentioned method eschewed the intensive computational challenges of incremental dynamic analyses to nd collapse probability. By the proposed approach, the pulse period impact was incorporated into collapse risk using probabilistic equations. After the role of axial load ratio was illustrated, the resulting collapse probability distributions and the corresponding risk values were obtained for a near-fault site. The results explained that as the connement ratio descended, the collapse capacity with near-fault pulse effect was decreased and the risk values were raised, consequently. In addition, the results were found in compliance with ASCE acceptable risk value.