Dynamic performance of prestressed ECC-concrete composite T-beam bridge subjected to close-in blast loading

To enhance bridge resilience against extreme loads, the Engineered Cementitious Composites (ECC) was employed to improve the blast resistance of T-beam bridges in this study due to its high ductility and energy dissipation. A novel ECC-concrete composite T-section was designed and validated through blast tests. To further investigate the dynamic performance of prestressed ECC-concrete composite T-beam (PECT) bridge subjected to close-in blast loading, explosion test was conducted on three scaled-down T-beam bridge specimens. And a high-precision numerical analysis model was established using LS-DYNA and validated by the test data. The dynamic behavior of ECC was also accurately simulated using the K&C concrete model. Experimental and numerical results highlighting that the PECT bridge processed excellent deflection and local damage control capabilities, with a reduced mid-span flange damage compared to ordinary concrete T-beam specimen (PCT). Moreover, increasing the thickness of web ECC layer can significantly reduce peak deformation of the structure. And the application of ECC in flange helped control damage and maintain lateral integrity, but also increased the total energy input into the structure and reduced stiffness. Thus, rational matching of the ECC layers thickness in the composite section is crucial for enhancing blast resistance. This study provides valuable references for the assessment and design of ECC-concrete composite structures under explosive loads.