Numerical and experimental analysis of composite beams for bridges under repeated loading

Abstract

A theoretical and computational model is developed to analyse the evolution of crack width and deflection in composite beams. The time dependent behaviour of concrete and the bond degradation between concrete and steel under repeated loading are considered. In the experimental part of this work, a 1:1 scale composite beam similar to those often used in small spans bridges was tested. The model consisted of a precast-prestressed I-section beam and a cast-in-place concrete slab. The tests were carry out when the beam was three years old and therefore most of the stress losses had already been developed. The model was tested under bending until 5,000,000 cycles of load. The comparison between the predicted results of the model and the experimental data show a good agreement. Also, the numerical model was compared with experimental results reported by other researchers with good agreement too. Some modifications in the model are suggested in order to estimate the behaviour of this beams in service more accurately.