基于刚度及经济的CFRP与钢组合拉索设计理论

基于钢斜拉索、碳纤维增强塑料(CFRP)斜拉索适用跨径研究结果,针对1 400~2 800 m主跨斜拉桥整体刚度不足提出一种新型结构方案,即基于刚度及经济性能的CFRP与钢组合拉索方案.该方案将CFRP斜拉索与传统钢斜拉索同时应用于斜拉桥中,将２种材料高强轻质及弹性模量高的优点进行组合,以充分提高斜拉索的等效刚度,进而提高斜拉桥的整体刚度.详细介绍该组合方案设计思路与方法,通过比较等效刚度以及经济性能给出２种材料斜拉索推荐组合比例.最后,通过一座1 400 m主跨CFRP与钢组合拉索斜拉桥试设计说明该方案相对传统方案整体刚度上的优势,证明其工程应用的可行性,是主跨为1 400~2 800 m斜拉桥的优选方案之一.

Design of CFRP and Steel Composite Stay Cables Based on Stiffness and Economic Behavior

Based on the study of appropriate spans for using steel or carbon fiber reinforced polymer (CFRP) stay cables,this paper proposes a new design of CFRP and steel composite stay cables to deal with the drawback of low stiffness,especially for the cable stayed bridges with main spans of 1 400~2 800 m.More specifically,the CFRP stay cables with high strength to weight ratio and steel stay cables with high elastic modulus are combined together for application in cable stayed bridges,which can increase the equivalent stiffness of stay cables and then improve the entire stiffness of bridges.The design strategies for the composite cable stayed bridges are proposed in detail.Then through a parametric study concerning the equivalent stiffness and economical behavior,the proper area ratio between CFRP and steel stay cables are also proposed.Finally,the feasibility of the proposed stay cables is discussed through a case study of a cable stayed bridge with 1 400 m main span.The proposed composite stay cables demonstrate a high equivalent stiffness, which is an excellent selection for bridges with main spans of 1 400~2 800 m.