Expected seismic performance of irregular medium-span simply supported bridges on soft and hard soils

Abstract

This paper presents the parametric study of irregular RC bridge structures subjected to strong seismic records. We determine the expected damages and the concentration demands on short piers of bridges with columns of unequal height located on soft and rigid soil sites. Medium length span bridges are analyzed using the most common structural configurations built in many countries with several height pier configurations. The structures were subjected to strong seismic ground motions recorded on soft and hard soils of earthquakes generated at subduction seismic sources. The parameters of interest in the study are the strength and stiffness characteristics of the substructure and the influence of the dynamic characteristics of the seismic records. The parameter combinations produced more than three hundred 3D non-linear time history analyses conducted with the Perform-3D software. Based on the evaluation of damages indexes, we determine the pier expected damages and the importance of the soil type, on the behavior of irregular pier bridge substructures. It is also quantified the impact of the pier configuration in the global behavior of the bridges and the influence of the shortest pier in the expected damages of the other piers. In most of the cases, the piers adjacent to the tallest piers of the bridge were the elements more affected by the irregularity.