Analytical models to predict structural behaviour of reinforced concrete beams bonded with prestressed fibre-reinforced polymer laminates

Abstract

The strengthening of reinforced concrete members with prestressed fibre-reinforced polymer laminates has been investigated by researchers due to major improvements in member serviceability characteristics. Currently, analytical models generally employ mostly empirical procedures in predicting member behaviour, and as a result, the analytical results exhibit poor correlation to experimental investigations. In this article, an analytical model is developed using new and existing theoretical techniques to critically analyse strengthened reinforced concrete beams for a range of loading scenarios to generate moment-rotation and load-deflection relationships. The prestress level and the intermediate crack debonding strain of the prestressed fibre-reinforced polymer laminate with the inclusion of mechanical end anchorage were highlighted as key parameters within the model. The proposed model adopts closed-form solutions to allow for a wide range of beams with varying steel and fibre-reinforced polymer reinforcement ratios and dimensions. The model incorporates calibrated crack spacing theory to predict the crack width and spacing as well as the length of the cracked region in the beam. The models have good correlation with collected experimental data and thus can be used for the analysis of reinforced concrete beams strengthened with prestressed fibre-reinforced polymer, throughout all stages of loading from serviceability to failure.