A New Punching Shear Equation for Two-Way Concrete Slabs Reinforced with FRP Bars

Synopsis: Recently, there has been a rapid increase in using the non-corrodible fiberreinforced polymers (FRP) reinforcing bars as alternative reinforcements for concrete structures especially those in harsh environments. The elastic stiffness, ultimate strength, and bond characteristics of FRP reinforcing bars are quite different from those of steel, which affect the shear capacity. The recently published FRP design codes and guidelines include equations for shear design of one-way flexural members. However, very little work was done to investigate the punching shear behavior of two-way slabs reinforced with FRP bars. The current design provisions for shear in two-way slabs are based on testing carried out on steel reinforced slabs. This study presents a new model to predict shear capacity of two-way concrete slabs that were developed based on extensive experimental work. The accuracy of this prediction model was evaluated against the existing test data. Compared to the available design models, the proposed shear model seems to have very good agreement with test results with better predictions for both FRP and steel-reinforced concrete two-way slabs.