Column-supported two-way slabs constitute a basic structural system in concrete buildings. With the increasing use of Glass Fibre Reinforced Polymers (GFRP) in concrete construction, questions arise as to how to use GFRP effectively as two-way slab reinforcement. The design of two-way slabs is usually governed by serviceability concerns and by the punching shear capacity of the slab-column connections. Available design rules are based on tests of steel-reinforced concrete slabs. These require modification to account for the lower stiffness and non-yielding nature of GFRP. This paper reports test results of four full-scale isolated interior slab-column connections. Two of the slabs were reinforced with GFRP deformed bars, one with a GFRP NEFMAC 2-D grid, and one with ordinary steel. The main variables were the reinforcement type (steel or GFRP), the reinforcement content (0.87 to 1.73%), and the reinforcement's cross-sectional shape (rounded or rectangular). Specimens were loaded to cause a punching shear failure. Slabs were heavily instrumented to identify their predominant load transfer mechanism. Tension stiffening is found to play a larger role in the behaviour of GFRP reinforced slabs than it does in steel reinforced slabs. Results suggest that bond between GFRP and concrete influences the shear behaviour of GFRP-reinforced concrete two-way slabs.
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