Seismic performance of pier under curved bridge decks with emphasis on ground motion direction

Abstract

The performance of the bridges during seismic occurrences is a key problem for curved highway bridges, where the curve angle and other variables complicate the study. Though several research studies have been conducted on this subject, many fail to consider the effects of the direction of seismic motion on the reactions along the pile depth in curved decks. This omission must be addressed to get a deeper knowledge of how bridges respond to seismic loads. So, this study focuses on the analysis of the straight and curved box-girder bridge decks supported by shaft piles using the finite element method, with an emphasis on time history analysis to evaluate the seismic responses. The curvature angle ranges from 0 to 60 degrees. Ground motion data from the 1940 Imperial Valley earthquake (7 Mw) at El Centro is used to assess the seismic response, which is obtained from the PEER database. This research investigates the relationship between pile depth and responses (axial force, shear force, torsional moment, bending moments, and deflections) in all three pile directions. The ground movements are taken into account in all three directions, with the excitation vertically being scaled to two-thirds of the total ground motion. With notable responses seen in the top part of the pile, the results show that vertical excitation is crucial to pile design. The highest reactions for axial force, shear force, torsional moment, bending moment, and deflection happen during lateral stimulation, but the curvature angle has the most effect during longitudinal ground motion. The curve angle effect is more at the upper part of the pier, and then this effect is decreased with the pile depth. The results show that, in contrast to straight bridges, curved bridges require more robust design standards for their fundamental parts.