Full-scale reinforced concrete slabs: blast effects, damage characterization and numerical modelling

Abstract

This work investigates the response of a blast loaded reinforced slab with different constructive characteristics. This topic has been well covered during the last years, but there are a reduce number of them that presents blast test at realistic scale. Seven different slabs were tested: three at a scaled distance of 0.79 m/kg1/3, one at 0.41 m/kg1/3 and four with 0.20 m/kg1/3. The three tests with high-scaled distance, used as calibration tests, have been characterized with pressure gauges and accelerometers. These reinforced slabs are the same as the one of low-scaled distance and one of high-scaled distance. Finally, the two tests of low-scaled distance have different reinforcement: steel or polypropylene fibres. The blast effects over the slabs has been characterized with a non-destructive methodology based on the Schmidt hammer. The methodology consists on the evaluation of a statistically significant difference of six rebound values before and six after a blast event for each evaluation point, having 19 evaluation point for each slab face. based on each individual damage value, damage maps have been created using an interpolation tool. This methodology is very useful to quantify the non-visual damage of a structural element and to validate numerical modelling results. In this case, a 3D lagrangian simulation using the lS-DYNA code with the blast load routine called cONWEP was done. The results in the developed model are affected by the scaled distance and by the construction patterns. The blast resistance of the slabs were better when using steel or polypropylene fibres, especially under tensile stresses (bottom part of the slabs).