Ductility-Based Seismic Vulnerability Assessment of RC Bridge Piers

In this paper, a qualitative approach, selected to estimate the seismic vulnerability index of reinforced concrete bridge piers in terms of ductility is presented. Samples of three bridges that are representative of RC bridges in Algeria were identified to carry out this study. For each structure, the sectional ductility was first computed using a multi-layered sectional analysis program (Extract). Structural ductility values were then obtained with a simplified pushover analysis carried out with a non-linear finite-element program (Seismostract). Then, the ductility demand was obtained from time-history analyses, using six ground motion records for Algiers and its surroundings (Nonlin program). Based on the Priestley theory, the ductility values were then used to elaborate a ductility index to be used as a preliminary evaluation criterion for seismic vulnerability assessment of bridge piers. The calculated ductility demand (required ductility) when compared to the ductility capacity of the selected bridge bents could be used in a seismic vulnerability assessment to identify the seismic behavior of bridge piers and to make a decision as to its safety or strengthening.