Seismic LRFD Criteria for RC Moment‐Resisting Frame Buildings

Abstract

This paper presents a study to develop reliability‐based seismic design criteria for reinforced‐concrete intermediate moment‐resisting frame buildings. The seismic criteria in the LRFD format are established on the basis of the collapse of a frame system rather than the failure of a member. A reliability analysis method has been developed to calculate the annual collapse limit‐state probabilities of representative frame structures classified as ordinary buildings. These probabilities are then used to determine seismic‐load factors by means of optimization with respect to the specified acceptable risk levels. The seismic‐load factors have different values in various seismic zones. To achieve more stringent acceptable risk levels required for high‐risk and essential buildings, the importance factor is used to increase structural strength and stiffness. Therefore, the seismic LRFD criteria developed in this study are applicable to three categories of buildings (ordinary, high risk, and essential) in various seismic zones in the United States.