Discussion on the Design of Cable Tower Grouping-Anchorage System of Cable-Stayed Bridge

Abstract

Cable tower grouping-anchorage system of cable-stayed bridges is a new type of anchorage system, which is only used in Chi-Zhou bridge in An Hui province domestically. In order to understand the behavior characteristics and the design methods, this study took Chi-Zhou Bridge as an example. Firstly, the propaedeutics were introduced, and then the finite-element models of the whole bridge were built in six different cases and parameters’ sensitivity were analyzed which included cables layouts, agglomeration forms, and steel beams design. This study then introduced the beam-column stiffness ratio, studied the stiffness matching between concrete tower and steel beam, and clarified the influence of grouping, agglomeration, and stiffness ratio on the whole bridge. Some design suggestions were stated. The results showed that the grouping-anchorage system is more advantageous on the lateral stability and torsion resistance of the whole bridge; the steel beams are the key point of design because of the stress complexity. Changing the length of the steel beam will bring about changes in the local stress and changing the space between steel beams will bring about changes in the whole bridge. Considering the layout spaces and detailing requirements, the length of steel beams should be reduced as much as possible, so as to improve the efficiency of stay cables, which is beneficial to the whole bridge stress and economy.