Punching shear analysis of post-tensioned slabs

Abstract

Experimental results and conclusions about punching shear slab failures are presented. The main analysed aspects are the strength influence of the shear reinforcement (studs) and the post-tensioning with unbonded tendons for an intemal slab-column connection. All the models have the same dimensions (square of 2500mm, depth of l 60mm) and are centrally loaded through a square metallic plate with side equal to 180mm. The mean value of the compressive strength of concrete is 50MPa, measured by standard cylinders. A comparison between the experimental results and those given by standards is presented. The following ones are considered: fib (1999), FIP (1999), ACI318 (1999), and the Brazilian Code NBR6118 (2003). This comparison intends to verify if the codes accurately predict the connection punching shear strength.