Design Optimization of a Continuous Railway Bridge with Prebent and Prestressed Composite Decks

Abstract

In the past, a significant effort was made to research long-term behavior analysis of a kind of prebent and prestressed composite steel-concrete beam used extensively in simply supported railway bridge decks in Belgium, which have U- shaped cross sections and are trough type. Extensive experimental research has been performed in tandem for the Belgian steel-concrete prebent beams to very high performance concrete (VHPC) technique. VHPC's main advantage over the C50 concrete currently used is prestressing system loss decrease due to a significant creep deformation decrease. Development of realistic models for continuous railway bridge construction feasibility assessment by connecting such simple decks over intermediate supports was a research motivation. A paramount condition for railway bridge decks is no cracking under load, which implies devising, between the simply supported decks, a form of in situ connection prestressing. To be able to cope with multiple construction and loading phases for such a highly heterogeneous structure, a structural analysis program was developed. Beam-type displacement-based finite element analysis is the framework within which the structural analysis is performed. The superposition algorithm forms the basis of a step-by-step time-dependent analysis. The CEB-FIP MC 90 creep and shrinkage model was found to reproduce recorded laboratory creep and shrinkage test strains for the C80/95 VHPC and the C50/60 concrete of the singly supported decks. Yue and Taerwe's proposed two-function method's step-by-step time-dependent analysis accommodates creep recovery effects occurring at unloading. This paper's purpose is to present a continuous bridge with prebent and prestressed composite decks' construction phases design optimization study. There is analysis of the continuous bridge's long-term behavior's most influential parameters.