Behavior of RC Slabs subjected to Eccentric Punching Shear

Abstract

Eccentric punching shear loads most likely take place on flat plate floors. This type of structure has been investigated experimentally and analytically by many researchers. Most of those experimental studies have dealt with slab specimens as a free – edge supported. This testing technique audits, in turn, slab specimen edges to leave the free support when exposed to an eccentric shearing load. So, slab deformed shape, in this case, does not represent that of the real floor slab when subjected to eccentric shear loading. This work investigates the behavior of the slabs under eccentric punching shear loads with the most realistic different techniques of the true slab condition and certainly gives more accurate results. Flat plates with concrete dimensions (600 x 600 x 60) mm were tested under variable eccentricities (50 – 70 – 100 )mm. Also, the effect of the flexure reinforcement ratio was studied. The ultimate load capacity, central deflection, cracking progress and pattern of cracks are recorded and discussed. The failure loads were compared to those calculated from different design codes. It was concluded that increasing eccentricity leads to a reduction of failure loads. Also increasing flexure reinforcement increases the failure loads. Moreover, it was observed that the expected failure loads from different design codes were lesser than the experimental results.

Keywords

• punching shear loads
• column slab connection
• and edges conditions