Evaluation of deflection prediction models for reinforced concrete structures

Five groups of simple span reinforced concrete beams with various parameters of loading, materials strength and reinforcement steel ratios were tested in order to obtain their service load-deflection relationships. The experimental results are compared with the analytically predicted deflections using the three models of ACI, Branson and Ning et al., which are used for estimating the effective moment of inertia of reinforced concrete sections. From the comparison, it is concluded that the three models would provide an overestimate for the analytically predicted deflection at the service-load limit. This paper compares the results provided by the three models, identifies the parameters which influence the accuracy of the analytical predicted deflection, and discusses the possibility of modifying some parameters in order to predict more accurately the deflection of the reinforced concrete structures.