Crack Width Control in Reinforced Concrete Two-Way Slabs

This investigation covers the effect of two-way action on crack width development in both centrally loaded and uniformly loaded slab systems of varied boundary conditions. As a result, criterion is developed whereby more but narrower flexural cracks of orthogonal pattern can be precipitated, thereby control of crack width development in two-way concrete floor slabs. A cracking hypothesis is presented and verified by tests on 22 centrally loaded slabs 5 ft 8 in. x 5 ft 8 in., and 32 uniformly loaded slabs 5 ft 0 in. x 5 ft 0 in. The size and spacing of the wire reinforcement are varied to extremes. A grid index is proposed as a measure of crack control in two-way slabs under different boundary as well as loading conditions.