Reevaluation of Deflection Prediction for Concrete Beams Reinforced with Steel and Fiber Reinforced Polymer Bars

Abstract

This paper provides a critical evaluation of equations commonly used to compute short-term deflection for steel and fiber reinforced polymer (FRP) reinforced concrete beams. Numerous proposals have been made for FRP in particular, and the different approaches are linked together by comparing the tension-stiffening component of each method. Tension stiffening reflects the participation of concrete between cracks in stiffening the member response. The Branson equation used in North America and other parts of the world is based on an empirically derived effective moment of inertia to calculate deflection. The tension-stiffening component with this method is highly dependent on the applied level of loading relative to the cracking load as well as the ratio of uncracked-to-cracked transformed moment of inertia