Influence of modeling parameters on the response of degrading systems to near-field ground motions

Abstract

The influence of modeling assumptions on the seismic response of structures subjected to near-field ground motions is investigated. Emphasis is given on degrading systems, since real-world structures do not have infinite displacement capacity as many inelastic models assume, while such systems are able to explicitly take into consideration the effect of stiffness and strength degradation. Near-field ground motions are of particular interest, since, compared to far-field records, may cause increased demand caused by the velocity pulse in their fault-normal component. Single-degree-of-freedom (SDOF) oscillators with generic multilinear force–deformation backbones are first considered in order to derive general conclusions for a wide range of periods. The effect of every parameter that describes the backbone is studied separately in order to identify the sensitivity of the demand when the system is subjected to pulse-like ground motions. Moreover, a nine-story steel moment resisting frame is studied in order to show that the observations made on SDOF structures extend to multi-degree-of-freedom buildings.