TESTS ON REINFORCED CONCRETE SLABS WITH PRE-STRESSING AND WITH TRANSVERSE REINFORCEMENT UNDER IMPACT LOADING

Current empirical formulae for design of concrete elements under impact loading are based on tests carried out on reinforced concrete elements with longitudinal reinforcement and they are applicable only to such elements. The influence of pre-stressing or transverse reinforcement is not taken into account. The aim of this test campaign carried out at VTT testing facility in Espoo, Finland, was to assess the influence of longitudinal pre-stressing and transverse reinforcement, separately and combined, on punching resistance of concrete elements under impact loading. Six tests presented in this paper were carried out on low aspect ratio concrete slabs under medium velocity hard missile impact. The variables were: the level of pre-stressing and the transverse reinforcement in form of T-headed bars. The results are presented in terms of scabbed concrete area and permanent deflection for each tested slab. It was observed that the level of damage of pre-stressed concrete elements without transverse reinforcement, in terms of scabbed area, was higher than reinforced concrete elements although the permanent deflections are lower. On the other hand, the transverse reinforcement reduces scabbed area as well as the level of permanent defections.