Parametric study of medium span bridges retrofitted with RC jacketing

Evolution of seismic codes and the average age of the bridges in the world require the evaluation of their seismic vulnerability. This study assesses the expected capacity, demand and damage of seismically deficient medium-length highway bridges, supported in frame-type piers using dynamic nonlinear methodologies. The non-retrofitted structures are 30-m span simple supported bridges with pier heights in the range of 5-25 m. The main emphasis of the study is the assessment of the jacket parameters’ contribution to the seismic vulnerability of bridges. Particularly, it is quantified how jacket thickness and reinforcement ratio affect the probability of reaching a particular damage limit state. The retrofitted scheme includes three jacket thicknesses and three longitudinal steel ratios. The results evaluate fragility curves to quantify the influence of RC jacketing on the seismic response and allow to select the best jacket parameters that improve the expected seismic behavior of the bridges.