Blast effects and damage characterization on reinforced masonry walls at full-scale

Abstract

It is of a great importance to find out materials that improve the response of different structural elements against a blast event. While there are many works about reinforcing structures, there are a reduce number of them that presents blast test at full-scale. The aim of this work is the comparison of different constructive solutions that are candidates to improve the integrity of brick masonry walls against moderate explosions. This kind of constructive elements produce in many cases, when structure does not collapse, more casualties due to spalling phenomena. A total number of 16 walls were performed at full-scale (measuring 2.5 m length, 2.5 m width and 240 mm of thickness) for this purpose. Charge for the tests ranged from 18 to 38 kg TNT Equivalent and was located at 5 m from the target. The scaled distance was selected so the damage on the wall was intermediate (in the halfway between collapse and little cracks) in order to detect differences among the solutions tested. Three alternatives of reinforcement have been developed: a fibered mortar, a recycled carbon fibre mesh impregnated with a semi-fluid epoxy adhesive and a polymer primed glass fibre mesh applied with a water and polyurethane-based adhesive. The blast event has been characterized using pressure gauges, accelerometers, high-speed camera and a laser-scanner. The resulting damage has been evaluated on both wall faces trough 20 defined points using a rebound hammer. Damage maps has been drawn for each wall doing an interpolation on 200 points. The damage has also been evaluated on terms of spalling, which is the mass of fragments launched during the test. According with the results, reinforcement influences the response significantly.