Field Tests on Spalling Damage of Reinforced Concrete Slabs under Close-In Explosions

Accidental explosions usually occur near the building structures. In order to protect the building structures against the near explosions, there is an urgent need for the study on the local damage of structural members under close-in explosions. However, the damage mechanism of the structural components under close-in explosions might be quite different from the case of distance explosions. In the case of the close-in explosions, the blast loads acting on the structural components are usually of high reflected peak pressure and concentrate on a local area, causing severe local damage to the structural member. For reinforced concrete (RC) structural members, it is much more complicated that the spalling damage might occur when they are subjected to blast load from close-in explosions. In order to investigate the damage mechanism of typical RC structural members under close-in explosions, field tests are carried out to study the spalling damage of RC slabs under different close-in explosions. The characteristics of the spalling damage of the test specimens are observed and presented. Comparisons are also made and the results show that the spalling damage of RC members under close-in explosions has a basic characteristic of uncertainty. And the increase of the height/diameter ratio of the cylindrical TNT charge will significantly increase the spalling damage degree of the RC slab, although the mass of the TNT charge is unchanged.