A New Method to Determine the Collapse Capacity and Risk of RC Structures Incorporating Pulse Period Effect in Near-Faultwith Considering Confinement ratio

Collapse capacity is one of the fundamental factors for evaluating of collapse risk in performance-based design engineering field. Calculation of this parameter has been time consuming during past decade. This issue has prevented engineers from determining this parameter in a prevalent and practical way. Furthermore, defining 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/Tp. In this study, amethod is proposed to obtain collapse capacity of reinforced concrete (RC) structures considering two main variables effecting columns behavior: axial load ratio and confinement ratio. The mentioned methodeschews the intensive computational challenges of incremental dynamic analyses to find collapse probability. By the proposed approach, the pulse period impact is incorporated into collapse risk using probabilistic equations. After the role of axial load ratio was illustrated,the resulted collapse probability distributions and the corresponding risk values are obtained for a near-fault site. The resultsexplain that asthe confinement ratio descends, the collapse capacity with near-fault pulse effect is decreased and the risk values are raised consequently. In addition, the results are found in compliance with ASCE acceptable risk value.