Reinforced Concrete Walls

AIR BLAST LOADING OF REINFORCED CONCRETE WALLS

Aseries of tests of 1/8-scale reinforced concrete walls of various designs were performed at Area 3 of the remote test site using detonation of a methane/oxygen gas mixture inside a rectangular shock tube to apply a uniform pressure pulse. The 25-mm-thick test walls formed the sides of a 0.5-m-tall by 1.6-m-long section of the shock tube and were built-in along all four edges to thick reinforced concrete roof, floor, and ends. The shock tube was filled with gas, which was initiated with a small explosive charge at one end. Thus, the walls were loaded with a rapidly sweeping pressure pulse rather than a reflected pressure pulse. This testing technique applies an essentially uniform flood pressure load with a simple exponential decay over the entire wall (the shock sweep time is very short) with independent control of peak pressure and impulse. High-speed movies were taken to illustrate the sequence of wall response: two-way bending/membrane, rupture at the roof and floor, formation of a vertical hinge in the middle, and breaking loose at the ends.