Uncoupled analysis of Rc-slabs under near-field air explosions: Examination of various empirical equations for simulating blast loads

In an uncoupled analysis, blast loads can be evaluated by empirical models and, then, applied to the structure in a separate response analysis. The literature includes a variety of empirical models. However, the potentials of these models may not be fully realized due to high variations that may exist in their outcomes, particularly at detonations with a relatively close standoff distance from the target. As such, the selection of an appropriate model should be made with special considerations. This paper investigates the effciency of various empirical models in blast analysis of the RC-slabs that are subjected to near-field air-detonations. The blast loads resulting from the empirical models are employed in a set of nonlinear FEA runs. Due to the proximity of detonations, the distribution of blast-overpressure across the concrete slab at any instant of time is nonuniform. A simplified approach that accounts for this nonuniform distribution has been developed and verified in this study. To examine the effectiveness of the empirical models, the FEA-results are compared with the observations made in a set of previous experimental studies. Based on this comparative study, the most effective empirical model is identified, and remarks are made on the performance of the other models.