Effect of Elevated Temperature on Punching Shear of Regular and Irregular Shaped Self-Compacted Concrete Slabs


The exposure of reinforced concrete slabs to high temperature causes changesin their structural behavior.This work aims to study the post-heating behavior of self compacted concrete(SCC) regular (square) and irregular (trapezoidal) shaped flat plates and assessingthe residual punching shear strength of these slabs.Twenty four reduced scale reinforced concrete slab specimens divided intotwo main groups (square and trapezoidal slabs), each of which consists of twelveslab identical in size and shape but different in concrete compressive strength(30,50,70) MPa. These specimens are subjected to different temperature levels(100, 300, 500) 0C and still heated in that temperature level for one hour using anelectric furnace and the results are compared with specimens tested at roomtemperature 25 0C.The effect of specimen shape, heating level, concrete compressive strength onthe punching shear resistance of slabs are discussed in details.Results indicate that the reduction in punching shear strength is ranged between(0 and 16) %, for square slab, at maximum temperature exposure (500) 0C, whilethis rate is ranged between (6.3 and 40.4) % for trapezoidal slabs. This indicatesthat the punching shear resistance of regular shaped slabs is higher than that ofirregular shaped slabs.