Experimental and numerical investigations on the dynamic response and damage modes of H-section steel columns subjected to near-field explosions

This study investigates the dynamic response and damage modes of H-section steel columns under close-in explosions (scaled distance Z = 0.33–0.47 m/kg^1/3) through combined experiments and numerical simulations. Four scenarios were tested with varying charge masses (2.4, 1.8, and 1.2 kg) and axial compressive loads (0 and 500 kN). Results show that a 500 kN preload increases maximum displacements by 32.5%–61.3%, leading to pronounced flange buckling. With increasing charge mass, failure modes shift from overall bending to localized deformation and eventual web penetration. The validated S-ALE numerical model accurately reproduced experimental observations, capturing the progression of damage from plastic strain concentration at flange–web connections to through-thickness web failure. Parametric studies further revealed the influences of charge shapes, detonation points, and axial preloads on column deformation. Overall, the experimental and numerical results provide insights for the blast-resistant design of steel structures.