Concrete Slab Damage and Hazard from Close-In Detonation of Weaponized Commercial Unmanned Aerial Vehicles

Explosives installed on a commercial unmanned aerial vehicle (UAV) may be carried and detonated close to a structural element. Although the explosive mass may not be large, the standoff distance is expected to be very small, and therefore, a potentially high-level of damage can be developed. A popular method to improve the performance of RC elements is by adding fibers to the concrete mix. In the current research, an experimental study is conducted to investigate the performance of RC slabs with and without steel fibers to close-in detonations, which aim to simulate an explosive installed on a UAV. The local damage is recorded and measured in terms of the crater diameters and depths. The structural damage is compared with available numerical tools. In addition, concrete debris from the rear face of the slab was collected and weighed, and their velocities were captured by a high-speed camera. The mass distribution of the debris, together with their velocities, led to a study on the damage hazards to potential occupants in the building.