To investigate the dynamic response of reinforced concrete frame structures under indoor explosion conditions， the study explored the failure modes of reinforced concrete slabs and beam-column joints through numerical simulation methods. Based on existing experimental data of reinforced concrete frame structures under internal explosion loads， a segregated single-layer single-span reduced-scale three-dimensional finite element model was established using the finite element software ANSYS/LS-DYNA. This study considered the shock wave propagation of explosive charge in the air domain， the fluid-structure coupling effect， and the influence of strain rate parameters on the material constitutive model. The simulation modeled the explosion of a 200 g explosive charge in the central area of the frame. The simulated results were in good agreement with the experimental results， validating the correctness of the material and parameter settings in the model. Additionally， the failure processes of the slabs and beams were analyzed， and overall， failure predominantly occurred at the junctions of the slab-beam and beam-column. By applying a controlled variable method， this study investigated the influence of parameters such as concrete strength grade and slab and beam reinforcement methods on the blast resistance of reinforced concrete frame structures. The results indicated that increasing the concrete strength grade enhanced the structure's blast resistance. However， after a certain degree of increase in concrete strength grade， further increments did not yield significant improvements. Using double-layer bidirectional reinforcement slightly reduced vertical displacement and concrete cracking in the top slab. Increasing the rebar diameter significantly reduced slab displacement but might increase concrete cracking. Properly shortening the length of rebars extending from the slab into the beam enhanced the blast resistance of the slab. To improve the blast resistance of frame beams， the method of increasing the diameter of longitudinal reinforcement inside the beam should be considered first， followed by the application of enhanced hoop reinforcement in heavily damaged areas. Increasing the diameter of the internal reinforcement of the reinforced concrete frame can improve overall blast resistance.
Qi et al. (Wed,) studied this question.