The influence of time-dependent phenomena in segmental construction of concrete cable-stayed bridges

Construction stages of a cable-stayed bridge are characterized by a sequence in which geometric configuration, restraints and consequently stress and strain patterns vary many times till the final arrangement is achieved. When construction of concrete bridges is made by cantilever method the influence of time-dependent phenomena becomes significant. In this study an evaluation of stay stressing procedures is given by taking into account creep and shrinkage in cantilever construction of concrete cable stayed bridges. A methodology of stay stressing is proposed with the final target of reaching the desired geometric configuration. Comparison with classical analyses performed by backward methodology is reported. A case-study is presented and discussed by performing analyses with different international creep models. Practical suggestions are given to designers, in order to minimize time-dependent effects on deck and stay internal forces and to reach an optimal final configuration.