Structural Assessment of Concrete Cable-Stayed Bridge after Replacement of Closure Segment: The Service Stage

To deal with failure in the closure segment in an existing concrete cable-stayed bridge, a new strengthening method, called the replacement of closure segment (RCS), has emerged in recent years in China. Basically, the construction process of RCS includes removing the failed closure segment, then constructing a new one, and finally improving the connection between the new closure segment and the original and residual part of the main girder by some strengthening measures. To assess the concrete cable-stayed bridge strengthened by RCS, a field loading test was implemented, and several structural indexes were investigated, including deflection of the bridge deck, horizontal displacement of pylons, concrete stress of critical sections in the main girder, and natural vibration characteristics. The results show that the concrete cable-stayed bridge after RCS behaves very well. The measured values of these structural indexes are very consistent with the analytical ones and tend to be safer. Thus, the strength and stiffness of the bridge structure after RCS can satisfy the load-carrying capacity and serviceability requirements specified in its original design. RCS opens up a new way and provides a beneficial exploration for strengthening existing concrete cable-stayed bridges during their use lifetime.