瓯江北口大桥缆索系统设计与施工

Design and Construction of Cable System of Oujiang River North Estuary Bridge

摘要:

温州瓯江北口大桥为世界首座三塔四跨连续钢桁梁悬索桥,采用双层桥面设计,其缆跨布置为230+800+800+348=2178m。首先为提高主缆抗滑移安全系数和主梁刚度,主缆失跨比采用1/10,吊索布置于钢桁梁下层；其次为解决刚性中塔处主缆与索鞍之间的抗滑移难题,大桥创新性的设计了高摩擦性能索鞍；再次为防止火灾对主缆造成不可挽回的损伤,在中跨220m缆梁相交区域专门进行了主缆防火设计；最后为解决窄间隙深鞍槽索股入鞍难题,研发了索股入鞍专用装备；另外为方便与主梁牛腿的连接并提高耐久性,采用销接式平行钢丝吊索。

Abstract:

Oujiang River North Estuary Bridge is the world"s first three tower four span continuous steel truss girder suspension bridge with the span of 230+800+800+348 m. Firstly, in order to improve the anti-slip safety factor of the main cable and the stiffness of the main beam, the loss span ratio of the main cable is 1/10, and the sling is arranged at the lower layer of the steel truss beam; Secondly, in order to solve the anti-slip problem between the main cable and the cable saddle at the rigid middle tower, the cable saddle with high friction performance is innovatively designed; Thirdly, in order to prevent irreparable damage to the main cable caused by fire, the fire protection design of the main cable is specially carried out in the intersection area of cable beam with a mid span of 220m; Finally, in order to solve the problem of cable strand entering the saddle with narrow gap and deep saddle groove, the special equipment for cable strand entering the saddle is developed; In addition, in order to facilitate the connection with the main beam bracket and improve the durability, a pin connected parallel steel wire sling is adopted.