Experimental response and numerical modelling of a full-scale two-span concrete slab frame subjected to blast load

•Full-scale blast testing of RC structure with successive explosive charges.•Maximum slab deflection of 42 mm after 3 blast test up to 20 kg TNT.•Crater generated in the RC slab about 66 cm diameter with 20 kg TNT at 0.5 m.•RC structures following EC2 can withstand explosive charges up to 20 kg TNT at 0.5 m. Three full scale tests have been carried out on the same structure to determine the effect produced by several blast loadings detonated at different times. The structure is a two-span 7.00 × 14.00 m2 RC frame subjected to explosives load from 10 to 20 kg TNT equivalent at distances varying from 0.5 m to 1.5 m. The tests were monitored using pressures gauges, accelerometers, high-speed camera and a 3D topography scanner for measurement of permanent deflections. The test results show the robustness of the slab, with only minor cracking damage in the first two loading scenarios and only local damage in the third scenario, where the equivalent load of 20 kg TNT is placed only 50 cm from the slab surface. The third test produced maximum deflections of about 4 cm and a local punching failure measuring 66 cm in diameter on the upper face and 82 cm in diameter on the lower face. The simulation of the building was carried out with the LS-DYNA software with a Lagrangian formulation for the walls, using the Load Blast Enhanced (based on CONWEP) module. Permanent defections and damage has been evaluated and has been compared with numerical modelling.