Non-linear analysis of polymer-strengthened concrete beams

Abstract

Commercial finite-element software was used to model the non-linear behaviour of reinforced concrete beams tested under four-point bending. Smeared crack analogy was employed in order to account for the changes in the local stresses and the concrete stiffness in the cracked region. Two models were analysed and compared to experimental data. The first was for a control beam and the second was for a carbon-fibre-reinforced polymer-strengthened reinforced concrete beam, which takes into account the adhesive layer characteristics which bonds the polymer strip to the concrete, using the cohesive tool in the software. Results showed that the models were able to predict the flexural behaviour of both beams with adequate accuracy. For the control beam, the first crack load, maximum load and the yield point were within 0, 15 and 7%, respectively, of the experimental results. For the mid-span deflection the model result was 59% away from the experimental value due to that fact that the finite-element solution did not converge beyond the 11 mm mid-span deflection. On the other hand, the maximum load first crack load and mid-span deflection for the strengthened beam model were within −4, 6 and 15%, respectively, of the experimental results.