Research on Cable Anchorage Systems for Self-Anchored Suspension Bridges with Steel Box Girders

Abstract

A new type of steel-concrete composite cable anchorage system is conceived and investigated preliminarily for self-anchored suspension bridges with steel box girders to optimize the mechanical behavior of the conventional cable anchorage systems. Model tests and 3D elaborate finite-element analysis (FEA) of the pure steel and steel-concrete composite cable anchorage systems are carried out for the Qingdao Bay Bridge Project, which is under construction in China. For the pure steel anchorage system, a complex stress distribution with obvious stress concentration is observed in the test. The FEA results of the stress distribution correlate well with the experimental measurements. The pure steel anchorage system adopted in the final design of the Qingdao Bay Bridge Project is reliable with a sufficient safety margin. In the contrast test of the composite anchorage system, owing to the composite effect between the steel and concrete, the stress level is reduced significantly and the stress distribution becomes more uniform in comparison with the pure steel anchorage system. The measured stress reduction rate of the composite anchorage averages approximately 40%, which is slightly smaller than the FEA results, and indicates the partial composite effect between the steel and concrete. The proposed composite anchorage system can effectively reduce the thickness and consumption of the steel plates, improve the mechanical behavior of the anchorage system, and simplify the fabrication and construction procedures.