Intensity Measures for Regional Seismic Risk Assessment of Low-Rise Wood-Frame Residential Construction

Abstract

Ground motion intensity measures (IMs) provide a link between the probabilistic seismic hazard analysis and probabilistic structural response analysis. IMs that are well correlated with the structural response allow an estimation of the seismic response of the structure with low uncertainty (i.e., high efficiency), reducing the computational effort involved in the structural response analysis. In this paper, the efficiency of 10 different IMs for estimating the seismic response of wood-frame single-family houses is evaluated and compared. Six nonlinear models of one- and two-story houses with varying fundamental periods are analyzed. Based on the results, the 5%-damped average spectral pseudoacceleration at a period of 0.16 s is the recommended IM for estimating peak interstory drifts and peak roof accelerations in wood-frame houses. On the other hand, for collapse assessment of wood-frame houses the filtered incremental displacement with one pulse segment, a 4 Hz cut-off frequency, and a period of 0.5 s, is the most efficient IM, followed by peak ground velocity which is also a very efficient alternative. Finally, an expression for the spatial correlation of 5%-damped average spectral pseudoaccelerations is developed for use in regional seismic risk assessments.