Numerical Prediction of Reinforced Concrete Exterior Wall Response to Blast Loading

Abstract

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.

Fracture Failure of Reinforced Concrete Slabs Subjected to Blast Loading Using the Combined Finite-Discrete Element Method

“…As a result, the damage of concrete slab can be separated into local and overall responses which occur at different time periods (Duranovic and Watso, 1994). The transition phase of effective strain rate from high to low at 10s -1 can be used to distinguish these two forms of predominant damage (Zhou et al, 2008). It is found from Figure 7 that the concrete slab started experiences low a n l h d mapped area of blast pressure time-history from a to n effective strain rate at time 0.5msec.…”

“…where p is pressure, e is internal energy, V is the specific volume, while A, R1, B, R2 and ω are all material constants than can be referred in Dobartz (1981) and Zhou et al (2008). The JonesWilkins-Lee is generally considered as a pure empirical equation of state with a non-physical coefficient considered to be constant.…”

“…The model of reinforced concrete slab was based on an experimental study by Zhou et al (2008). The concrete slab has dimension of 1300mm length, 1000mm width and 100mm thickness.…”

“…The compressive strength, tensile strength and density of concrete and steel were followed the data that provided by Zhou et al (2008). Meanwhile, the Young's modulus of concrete was simply calculated using the following equation:…”

Critical overview of blast resistance of different concrete types

“…Each P-I curve represents different combinations of pressure and impulse (time integral of pressure) that would produce the same level of damage within a structural element (Baker et al, 1983). These curves can be obtained by simple single-degree-of-freedom analysis, complicated numerical simulations, or conducting field blast tests (Lan and Crawford, 2003;Zhou and Hao, 2008).…”