Punching Strength of Reactive Powder Reinforced Concrete Flat Slabs

Abstract

This research is devoted to investigating experimentally the punchingshear strength of reactive powder concrete slabs under monotonicloading. All slabs have the same flexural reinforcement and samedimensions (1000mm length,600mm width,50mm thickness). Theexperimental program includes casting and testing of sixteen slabs testedunder monotonic loading. The major parameters adopted in the currentresearch include the shape of column (circle, square), column size (twocolumn sizes), number of columns (one, two), and the distance betweentwo columns (3d,5d,7d). Results showed that, the slabs with circularcolumn sections have slightly higher ultimate load than those with squarecolumn sections. An increasing column area increases the load ofpunching shear failure. It was found that the ultimate failure load forslabs with two columns is greater than the slabs with one column. Relatedto the effect of distance between the two columns for monotonic, it wasfound that the slabs maximum load reaches the maximum value atdistance between the two columns equal to(7d) for a circular section witha diameter of 85mm and 113mm and square section with dimensions of(100*100)mm. While the maximum failure load reaches the maximumvalue when the distance between two columns (d) for a square sectionwith the dimension of (75*75)mm. Related to the crack patterns, it wasnoticed that for slabs with larger columns sections with the distancebetween columns equal to 7d, the failure zone extended (in a largedirection) to the slab sides.