Assessment of a concrete cable-stayed bridge after replacement of the closure segment

摘要

The concept of replacement of the closure segment (RCS) emerged originally in a strengthening project for a concrete cable-stayed bridge and was intended to deal with a failure in the closure segment of the main girder. The construction procedure of RCS includes removing the failed closure segment, reconstructing the closure segment and finally improving the connection between the new closure segment and the original residual part of the main girder. Thus, a relatively complex conversion in structural state is involved. To assess the completed bridge after RCS, a finite-element model of a typical bridge is developed by using the software Dr. Bridge, and then a construction stage analysis is performed in the present study. Numerical results show that RCS eradicated the hidden structural safety danger while the structural integrity was improved to a certain extent. However, RCS had no significant influence on the geometric profile of the bridge deck, on the horizontal displacement at the top of each pylon and on tensions in the cable stays. As the stress condition in the new closure segment and associated joints between segments could not be improved by mere RCS, other strengthening measures should be taken to achieve a further structural state adjustment for the completed bridge. As a novel strengthening idea, RCS has a comparable advantage and remarkable economic benefit in dealing with local failure in the structure. Inevitably, it has some limitations in practical use.