Impact behavior of rehabilitated post-tensioned slabs previously damaged by impact loading
Accidental rockfalls are common hazards in many countries, where many structures and infrastructure are damaged by the impact of falling rocks. This research aims to study the efficiency of shear reinforcement as rehabilitation techniques for PT “post-tensioned” slabs damaged by falling rocks. Two simply supported PT slabs were considered in this study. Each has a dimension of (6.6 m×3 m×0.25 m) and was subjected to an impact from a 605 Kg reinforced concrete falling block at a height of 20 m. The first slab (PT-1) was hit at its center of gravity, while the second one (PT-2) was hit at the mid-span of its free edge. After impact, both slabs were repaired by replacing the damaged parts and adding shear ties in order to prevent any future collapse when new impact occurred. The impact test was repeated again after repairing, and both punching shear capacity and normal stresses were recorded. Results showed that the repaired slabs were able to resist the repeated impact successfully. Both punching shear and normal stress capacities were higher than the applied stresses. Moreover, using shear reinforcement helped in changing the crack pattern from shear to flexure. At the end of this study, some recommendations were suggested for further studies.