Effect of material variability on the seismic response of reinforced concrete box-girder bridges for different pier heights

Abstract

RC bridges situated in regions prone to seismic activity are susceptible to undesirable pier column movements and deck displacements. The component-level nonlinear response evaluation can give a better picture of the seismic safety of the existing bridge structures. Many times, the material strength variability also affects the inelastic response of the structures significantly. The present study looks into the effects of column heights and material strength variability on the seismic performance of reinforced concrete bridge models adopted from past investigations, subjected to bi-directional loading. Chosen suite of 40 far-field ground excitations are employed to simulate the seismic response of chosen models in OpenSees and their non-linear response is evaluated. The seismic response of the structure is evaluated as curvature ductility of piers (primary component), and deck displacements (secondary component). Fragility curves so obtained across the damage states considered depict the difference in seismic performance of the model considering only record variability and considering record and material strength uncertainties. The results showed that for the primary component, damage probability for different states is found to be increased under material variability irrespective of the column pier height, while secondary components showed an increase in the damage state due to material strength variability for the shorter pier.