Study on the Damage Characteristics of RC Beams under Explosion Impact Load

In order to obtain the damage pattern, damage criteria, damage effects and other damage characteristics of the reinforced concrete beams under the action of explosive impact load, this paper studies them by combining experiments and numerical simulation. A fast method was proposed to obtain the P–I curve of beam members with arbitrary structural parameters. First, five model tests were conducted to study the dynamic response and damage parameters of two types of the RC beams with cross-section widths of 0.04 and 0.047 m, when 200 g TNT exploded at two different action distances (0.2 and 0.5 m) and explosion locations (above 1/2 and 1/4 of span). The test results indicated that the damage to the RC beam was smaller when the cross-section width of 0.04 m was selected or the explosion position was above 1/2 of the span in the experimental research range. The experimental results verified the effectiveness of the numerical simulation method. Then, based on a large number of numerical simulation calculations, the fitting equation of the P–I curve of the RC beams was simplified, and the influence of structural parameters on the P–I curve was investigated, including the stirrup reinforcement ratio ρs, the longitudinal reinforcement ratio ρ, the concrete axial compressive strength $$f_{{\text{c}}}^{'}$$ , the beam span L, the beam section height b, and the beam section width a. Finally, the method for quickly determining the P–I curve of the RC beam members was provided, which can be applied in the field of target anti-blast protection design and rapid damage assessment.