Numerical prediction of reinforced concrete exterior wall response to blast loading

It is of interest to know the response of the unretrofitted reinforced concrete exterior walls under blast loading because some infrastructures might be targets of terrorist attack. Detailed numerical simulation and analysis of a typical concrete wall under different blast loads is presented in this study. The concrete material model used in the study includes a dynamic plastic damage model, a modified damage dependent piece-wise Drucker-Prager strength envelope, and a nonlinear equation of state considering the heterogeneity and porosity of concrete materials. The strain rate effect on tensile and compressive strength is considered separately. The concrete damage is based on Mazars' damage model, which combines tensile and compressive damage. The present numerical model was calibrated first by comparing the numerical results with laboratory blast test results of reinforced concrete slabs. The calibrated model is then employed to simulate the response of a typical reinforced concrete exterior wall under blast loads. TNT charge weights corresponding to some typical terrorist bombs, that is, from 10kg to 5000kg, are considered. In terms of different TNT charge weights, the responses of the reinforced concrete wall at different stand-off distances are simulated. Based on the numerical results, critical curves that relate damage levels with the explosion conditions are derived. The safe stand-off distances to resist different terrorist bombing scenarios are suggested.