Long-term deformation analysis of prestressed concrete bridges under ambient thermal and vehicle loads

Few studies have focused on the combined effects of ambient thermal and vehicle loads on the long-term deformation of prestressed concrete bridges. Based on preliminary work, a method for establishing the equivalence of random ambient temperature loads is proposed here. With this method, the temperature distributions of bridges under random weather conditions can be obtained. Subsequently, a concrete creep model considering cyclic thermal and vehicle loads is established. Finally, an analysis method for establishing the long-term deformation of prestressed concrete bridges under ambient thermal and vehicle loads is proposed. This was applied to the example of a prestressed concrete bridge; the meteorological parameters around the bridge were collected, and the equivalent environmental thermal loads were obtained. It was found that higher temperatures made the coupled effect of thermal and vehicle loads more obvious, leading to faster deformation. The long-term deformation of a continuous beam was found to be related to the residual stress after sunshine. The long-term deformation can be affected by the temperature-distribution mode, but the random properties of weather have almost no notable effect. The temperature difference between the inner and outer surfaces of the web and the prestress loss are the main reasons for the cracking of the inner surface of the web.