Dynamic Response of Reinforced Concrete T-Shaped Columns Under Blast Loading

To investigate the dynamic response and failure mechanisms of reinforced concrete (RC) T-shaped columns under blast loading, field blast tests on 1/2-scaled components were conducted in this study to systematically examine the effects of axial compression ratio and explosive charge mass on the macroscopic failure modes of the specimens. Based on the experimental results, a three-dimensional finite element model incorporating the fluid–structure interaction (FSI) algorithm was established and validated using LS-DYNA. Subsequently, a parametric analysis was conducted focusing on cross-sectional dimensions, axial compression ratio, detonation position, and explosive charge mass. The analysis indicates that the explosive charge mass directly determines the extent of structural damage. The influence of the axial compression ratio on the blast-resistant performance exhibits evident nonlinear characteristics; maintaining a moderate axial load or enlarging the cross-sectional dimensions can effectively suppress the dynamic displacement of the components and mitigate damage. Furthermore, eccentric blast loading induces severe coupled bending-shear deformation, substantially compromising the blast-resistant stability of the components. To quantify the degree of damage, this study proposes a three-level damage classification criterion (minor, moderate, and severe) for T-shaped columns, utilizing the maximum support rotation as the evaluation index. Finally, based on the equivalent single-degree-of-freedom (SDOF) theory, a theoretical three-stage resistance function model applicable to T-shaped columns was derived. The calculation results of this model are in good agreement with both experimental and simulation data, providing robust theoretical support for the blast-resistant design and post-disaster assessment of RC special-shaped columns.