Seismic performance of multi-span continuous reinforced concrete bridges considering flood-induced scour effects

Abstract

Flood-induced scours near the pier foundation are an adverse phenomenon that may cause the collapse of bridges. However, in the seismic design of bridges, the scour impact is commonly ignored when evaluating the seismic response. This study aims to quantify the effect of flood-induced scours on nonlinear static and dynamic behaviors of typical reinforced concrete bridges. For this regard, three-dimensional finite element models of two- and three-span bridges with a multi-cell box girder, circular column bent, and extended pile-shaft foundation are first developed, where the column bent is modeled considering the material and geometry nonlinearity. The interaction between the soil and structure is also accounted for by using soil spring models. By considering different scour depths, the modal, static pushover, and dynamic time-history analyses of the bridges in both directions are investigated. It is observed from the modal analysis that the fundamental periods of the bridges increase with the increase of scour depth. In addition, the results in terms of the column drift ratio show that scour may increase the seismic damage to the bridges, which transfers damage from the column bent to the pile-shaft foundation. The findings of this study exhibit the significant effect of the scour on the seismic damage of reinforced concrete bridges; therefore, it is recommended that this phenomenon should be considered in the bridge seismic design.