Towards efficient structural and serviceability design of high-strength concrete T-beams

Ten high-strength concrete (HSC) T-beams of total length 1700 mm, web breadth 100 mm, height 250 mm and different flange dimensions were experimentally tested until failure. The beam parameters studied were the flange dimensions and transverse and longitudinal reinforcement ratios. A numerical model was developed to predict the flexural behaviour of the tested beams. The results indicated that increasing breadth, depth and flange reinforcement ratio led to a reduction in the overall deflection and an enhancement of the ultimate load capacity. An empirical equation developed earlier by the authors for predicting the effective moment of inertia of HSC T-beams was successfully used to predict the load–deflection relationships of the studied beams. The load–deflection curves predicted by the numerical model, those predicted by this equation and those predicted by the Branson equation, which is currently used in design codes, were compared. Close agreement was found between the experimental results, numerical results and those obtained by the authors’ equation. This research thus highlights the need for updating the Branson equation used in design codes for deflection design of HSC T-beams by adopting the equation proposed by the authors.