Effects of construction process and slab prestressing on the serviceability behaviour of composite bridges

The study presented in this paper aims to evaluate the structural response under service conditions of composite bridges when considering different construction processes. Short and long-term stresses and strains, deflections and cracking of the concrete slab are analysed. The study, made over a real structure, has been divided into two parts. First, four construction sequences are considered in order to analyse the structural response of the bridge in each case. The second part is focused to study the effectiveness of post-tensioning the concrete slab to generate long term pre-compression. A numerical model, previously developed for the nonlinear and time-dependent analysis of segmentally constructed three-dimensional concrete and composite frames, has been used as the simulation tool. As the results show, the model has been proved to be capable of capturing the structural effects of the phenomena influencing the service behaviour of composite bridges. Consequently, relevant conclusions are obtained that lead to the most suitable construction solution depending on the most restrictive design criterion of the project. (C) 2002 Elsevier Science Ltd. All rights reserved.