Rapid assessment of local damage in reinforced concrete T-beam bridge decks under blast loading

Prestressed reinforced concrete (RC) T-beam bridges are commonly employed in highway bridges construction. After explosive attacks, the deck damage mostly exists in the form of breaches and affects its traffic capacity. While significant attention has been devoted to evaluating post-blast residual capacity of RC beam bridge piers and girders in existing blast damage assessment studies, there remains a critical gap in methodologies enabling intuitive and rapid damage assessment method for bridge serviceability. Therefore, the rapid assessment of bridge deck damage is investigated in this study by combining numerical simulation with multivariate nonlinear regression analysis, in which the breach size of the prestressed RC T-beam bridge deck subjected to explosive loading is taken as the damage index. Through comparative analysis of the transverse size of the deck breach under blast loading, it was revealed that concrete strength exhibits relatively minor influence, whereas parameters including explosion location, deck thickness, diaphragm spacing, TNT equivalent, and scaled distance demonstrate more pronounced effects. Owing to the pronounced reinforcing and constraining effects of webs and diaphragms on the bridge deck, comparative analyses under identical conditions demonstrate that transverse size of the breach caused by explosion above deck areas between webs and diaphragms is significantly smaller than that by explosion directly above the web, while on-bridge explosion exhibit lower damage compared to under-bridge explosion. Based upon the aforementioned parameters with significant influence, utilizing transverse size of the breach as the damage index, a rapid blast damage assessment formula is proposed for predicting the post-blast traffic capacity of bridges.