Damage Evaluation of Concrete Bridge with Steel Piers Subjected to Explosive Loads

The transportation system infrastructure in any country encompasses roads, highways, and crucially, bridges. Among these components, bridges hold significant importance. Throughout their operational lifespan, structures endure various loadings that impact their design and necessitate strengthening measures. Evaluating and assessing the behavior of bridges designed and implemented decades ago, adhering to outdated regulations but still serving as access routes today, is vital. Notably, certain older bridges, particularly those with steel piers, require special attention due to the effects of aging on their behavior and susceptibility to various loads, including explosive ones. Finding solutions for ensuring their safety and implementing rehabilitation measures becomes imperative. This paper delves into a case study on a communication bridge in Kazerun city, focusing on bridges with steel piers. The investigation explores the bridge's behavior under the influence of different explosive loads through finite element analysis. The LS-DYNA finite element software was employed for the necessary analysis, evaluating both the local failure of the bridge piers and the overall failure of the entire bridge using the support rotation criterion. The study reveals that, as the explosive charge weight increases, the permanent displacement in the concrete slab of the bridge rises, leading to a shift in damage levels from low to medium. Furthermore, incorporating steel beams in the longitudinal direction of the concrete slab proves effective in reducing deformation caused by explosive loads, subsequently minimizing damage. The proximity of a specific bridge member to the explosion center correlates with a higher local failure rate. Ultimately, the areas experiencing greater local failure witness a subsequent general failure of the steel piers, bringing the bridge closer to collapse.