Modeling,vulnerability assessment and retrofitting of a generic seismically designed concrete bridge subjected to blast loading

In this article,general procedures for vulnerability assessment and retrofitting of a generic seismically designed bridge are outlined and the bridge’s damage criteria for blast resistance are explained. the generic concrete bridge is modeled and analyzed with the finite element technique implemented in ansys ls-dyna environment and explosion threats are categorized into three main levels. uncoupled dynamic technique is adopted to apply the blast loads on the bridge structure; damage and performance levels are resulted based on quantitatively verified damage mechanisms for the bridge members. the results show that,among different loading scenarios,the explosions that happen under deck are more critical compared to blasts initiating from over deck sources. furthermore,two retrofitting methods: (1) concrete filled steel tube (cfst) and (2) concrete jacket are applied on the bridge columns. the program autodyn is used with coupled dynamic analysis of a column to compare the effectiveness of each method. afterward,more efficient method for a column is applied to the whole bridge and its efficiency is revaluated. it is shown that cfst can decrease concrete spall,scabbing,rotation,displacements and shear forces more than the concrete jacket. considering the proposed damage and performance levels,the bridge retrofitted with cfst reacts with lower damage level and higher performance level to blast loads. © iran university of science and technology 2016.