Effect of curvature radius on probabilistic evaluation of seismic horizontally Curves RC Box girder bridges using Monte Carlo simulation under three-dimensional excitations under Near-Field Earthquakes

Curved bridges exhibit complicated responses in the course of an earthquake, due to their distinctive geometric status. Thereby in this study, the effect of different curvature radii on the seismic damage probability of curved multi-frame concrete box-girder bridges was investigated and compared to straight bridge. Three-dimensional probabilistic seismic vulnerability of the curved multi-frame concrete box-girder bridges was delved in the near-fault events subjected to three-directional ground motion excitations (considering vertical component of earthquake). Bridge models were analyzed in 5 different radii subjected to 80 near-fault earthquake records and taking into account all demand uncertainties (14 uncertainties inherent of bridge, along with the earthquake uncertainty) as well as capacity uncertainties. Of all the bridges of this class, a total of 10 completely random geometries, representing geometric status of entire statistical population of curved box-girder bridges in California, were selected for each of the six bridge radii using the Latin-Hypercube Sampling technique. Having performed nonlinear dynamic analyses, the fragility curve of each bridge component was plotted, and the curvature effect on the vulnerability of various bridge components was investigated . Thereby, comparing seismic demand with the capacity of components through Monte Carlo simulation strategy, damage probability of the bridge system was estimated.