Repair of R/C flat plates failing in punching by vertical studs

In this paper, a system for repairing damaged flat plates as a result of punching shear is presented. The system depends mainly on repairing the damaged concrete and the addition of vertical studs with different arrangements through holes drilled in the plates. The experimental program consists of eight specimens with the same dimensions and flexural reinforcements, but with different concrete strength and shear reinforcement ratios. The main aim of the tests is to assess the efficiency of the suggested repairing system and to investigate the slabs load carrying capacity, deformation characteristics and cracking behavior. Test results showed that using the proposed system on repairing damaged flat plates due to punching shear is very efficient. Theoretical results obtained based on the formulas adopted by different codes and from the critical shear crack theory (CSCT), showed a satisfactory agreement with test results.