Structural System Parameter Selection Based on Collapse Potential of Buildings in Earthquakes

Abstract

This paper attempts to provide insight into the sensitivity of the collapse capacity of moment-resisting frame and shear wall structures to variation in basic structural parameters, and the choice of an appropriate ground motion intensity measure, based on probabilistic estimation of the collapse capacity of a structural system. The effects of fundamental period and base shear strength and of deformation and deterioration properties of structural components on the collapse capacity of frame and wall structures are quantified. It is shown that the collapse potential of moment-resisting frames is highly sensitive to the ratio of column to beam strength; increasing this parameter from 1.2 to 2.4 will increase the median of collapse capacity by up to 90%. Using a scalar ground motion intensity measure for estimating the collapse capacity can lead to underestimation of median collapse capacity by up to 50%, compared to using a vector-valued intensity measure. The provided information can be used to assist in the selection of a suitable structural system and associated parameters in design for collapse safety. Closed-form solutions are formulated using a database of collapse fragility curves developed for the sensitivity study. Application of these closed-form solutions for design decision making is illustrated through a comprehensive example.