A new damage assessment model considering quasi-static pressure for building components under internal explosion

Damage assessment of structural components under internal explosion is a key technology for quantifying weapon damage effects. However, the existing assessment models do not account for the damage enhancement of quasi-static pressure. Therefore, this study integrated theoretical modeling with test verification, established an equivalent calculation method for internal blast loadings, and proposed a damage assessment model considering quasi-static pressure for reinforced concrete (RC) components. The specific procedure is as follows: the overpressure time history at shock wave pressure stage is calculated based on the method of images and the nonlinear superposition principle; the overpressure time history at quasi-static pressure stage is calculated based on thermodynamics and energy theory; the equivalent overpressure and duration during the shock wave pressure stage is derived based on the virtual work principle and the impulse equivalence principle; the maximum deflections of components are calculated through the single degree of freedom (SDOF) method; and the damage levels are determined according to the damage assessment criteria. The results show that the proposed calculation method enables high precision equivalence of the internal blast loadings. The damage assessment model enables accurate prediction of the dynamic responses and damage levels of components, and the predicted results show good agreement with test data. Quasi-static pressure is a critical factor contributing to the aggravation of structural damage, accounting for up to 70% of the maximum displacement. The damage enhancement effect of quasi-static pressure on components should not be neglected in the blast-resistant design of building structures and damage assessment of weapons.