Blast Resistance of Retrofitted Unreinforced Masonry Arch Bridge with Reinforced Concrete Pavement and Infill Replacement

This study investigated the impact of blast loads on the structural integrity of masonry arch bridges and proposed two reinforcement methods to enhance the resilience of the bridge under consideration. A detailed micro-model was developed utilizing finite element software based on data obtained from FARO laser scanning. Various material models including Johnson-Holmquist II (JH-II), Mohr–Coulomb, Johnson–Cook, and Concrete Damage Plasticity were utilized to characterize the properties of masonry units, backfill, steel rebars, and concrete. The Jones-Wilkins-Lee equation of state was employed to simulate the characteristics of trinitrotoluene. Following the JH-II model theory, the authors developed a VUMAT code. Explosive charges ranging from 100 to 500 kg were located above and below the bridge deck. The findings indicated that TNT charges below 100 kg placed above the deck caused minor damage to the bridge without compromising its stability. Conversely, charges exceeding 500 kg had a notable effect on the structural integrity of the bridge. Moreover, explosions occurring beneath the deck had a more severe effect on the bridge compared to those above the deck. Furthermore, the implementation of reinforcement techniques mitigates component damage and prevents the potential structural failure of the span and/or bridge.