Long-Term Performance of Steel-Concrete Composite Box Girder

In this paper, an analytical example was given to show the time-varying regularity of stress and deformation of composite box girder. The distribution of deflection along the span at initial time and ultimate time was calculated. It was found that the mid-span deflection increased rapidly during the initial 50 days, and became stable after 300 days. The stress of steel increased while the stress of concrete decreased and both of the variation rates gradually slowed down with time. The regularity of stress of steel and concrete with time are similar to that of the mid-span deflection.