Steel-concrete-steel sandwich composite pylons for cable-stayed bridges: structural behaviour of cable anchorage

Abstract

The cable-stayed bridge pylon is an important load-bearing component in bridges, especially the anchorage zone, which requires both high stiffness and load-bearing capacity. The steel-concrete-steel (SCS) sandwich composite structures provide a new alternative structural form for bridge pylons with excellent strength, stiffness, and cost-effectiveness. Besides, the modular construction of SCS sandwich composite bridge pylons achieve higher construction efficiency than traditional concrete bridge pylons. A 1:2 scaled model test was designed according to the actual project to investigate the structural behaviour of SCS sandwich composite cable anchorage under cable loading. Firstly, the stress distributions and load-displacement curves of inner and outer steel plates, and concrete cracks in the pylon anchorage zone were analyzed. Further, a simplified frame model was adopted to analyze the stresses in the cable pylon anchorage, which demonstrated that the SCS sandwich composite structures can improve the structural performance of cable anchorage. In addition, based on the finite element model verified by experimental results, the effects of section steel ratio, load-bearing plate area, section reinforcement ratio, and concrete strength on the load-bearing capacity and stress distribution in the anchorage zone were investigated. The results show that within a certain range, increasing the reinforcement ratio and load-bearing plate area can significantly increase the load carrying capacity of the cable anchorage, while the effects of increasing the cross-section reinforcement ratio and concrete strength are insignificant. The results of this paper can provide guidance to engineers in the practical application of SCS sandwich composite pylons.