PUNCHING SHEAR STRENGTH AND DEFORMATION CAPACITY OF R.C. SLABS WITH DIFFERENT PATCH LOAD AREAS

Abstract

ABSTRACTThe main objective of this paper was to evaluate the effect of using different supporting areas or patch loads on a reinforced concrete slab within the slab-column connections. The increasing of the punching shear strength and deformation capacity when subjected to patch load was studied here. An experimental study was carried out on reinforced concrete slabs under a central patch load with circular, square and rectangular shapes of patch areas. A single concrete mix design was used throughout the test program. All of slab specimens were reinforced with distributed mesh reinforcement with equal steel ratios in both directions. The validation of the experimental work was made by analyzing the tested slabs by finite element method under cracking load. The results obtained by the finite element method were found to compare well with those obtained experimentally. In order to calculate the ductility for the tested slabs, the punching load has been determined by applying the published failure criterion and a load-rotation relationship obtained from semi-empirical relationship for the tested slabs. Conclusions on the influence of patch area on the punching shear capacity of reinforced concrete slabs were drawn. The experimental results confirm that the strength and deformation capacity are slightly influenced by the shape of the patch area. Among all specimens, the slabs with circular shape of patch area exhibited the best performance in terms of ductility and splitting failure.