超大跨径部分地锚交叉索斜拉桥的概念设计

Conceptual Design of Super-span Cable-stayed Bridge with Partial Ground-anchorage and Cross Stays

提出了一种适用于跨径1 500 m左右斜拉桥的原创设计方案,即"部分地锚交叉索斜拉桥",其主要特点是将长索交叉并锚固于地锚,使长索不对主梁产生水平压力。研究表明该方案具有以下显著优势:大幅度降低了斜拉索引起的主梁水平压力;交叉索有效提高了跨中区域的刚度;由于交叉索提供了双重竖向支撑,水平力又相抵,因此长索倾角可以适当减小,塔高可以降至L/5.5左右;长拉索在跨中区域形成索网结构,有效改善了长索的气动性能。

This paper presents an original design scheme of super-span cable-stayed bridge,namely,a cable-stayed bridge with partial ground-anchorage and cross stays,which is appropriate for cable-stayed bridges with main span length around 1500 m.Its main characteristic is that the long stays cross with each other and are anchored in the ground-anchorage,and thus the long stays result in little horizontal pressure force in the main girder.Studies show that the proposed novel cable-stayed bridge system has the following significant advantages over conventional ones：① Horizontal pressure forces in the main girder caused by cables are greatly reduced;② The cross stays effectively increase the stiffness of the girder in the span-center region of the main span;③ As the cross stays can provide dual vertical supports and balance horizontal forces with each other perfectly,the horizontal angle of long stays can be reduced and the height of tower be decreased to only about 1/5.5 of main span length as a result;and ④The long stays form a network in the span-center region of the main span,which effectively improve the aerodynamic performance of the long stays.