空间倾斜塔柱曲线人行斜拉桥设计关键技术

Key design technology of curved cable-stayed pedestrian bridge with spatial inclined pylon

无锡市映月湖人行桥造型新颖独特,结构形式为三跨独塔双索面异形斜拉-刚构桥,两根圆形细长塔柱各自独立空间倾斜设置,双塔呈V字形,斜拉索为空间布置.主梁横向及纵向均呈波浪形,全桥呈现为S型反对称的空间形态,倾斜塔柱长径比达到35.6.本桥主塔及梁体皆为空间结构且尺寸较小,受力复杂,稳定与平衡问题突出,建筑形态与结构的矛盾较为尖锐.结构设计时针对梁体反扭形态所带来扭转作用力,通过调整索力控制梁体平衡,并在桥塔位置采用圆形承台形式抵消扭矩.通过合理布置跨径增大桥梁刚度,减少中支点负弯矩值.钢-砼组合梁桥面板采用预应力群钉锚固技术,并针对人行桥的舒适度问题进行了专题研究,预留阻尼器连接构造措施.文中介绍了该斜拉桥结构设计中的关键技术问题及措施.

The pedestrian bridge across Yingyue Lake in Wuxi City has a novel and unique shape.The structural form features a three-span single tower double cable plane and a special-shaped as well as cable-stayed rigid frame.Two circular slender towers are set independently and inclined in space.The double towers are V-shaped,and the stayed cables are arranged in space.The transverse and longitudinal of the main beam are wavy.The whole bridge presents an S-shaped antisymmetric spatial shape,and the length-diameter-ratio of the inclined tower column reaches 35.6.The main tower and beam of the bridge are spatial structures with small size and complex stress,which creates prominent problems regarding stability and balance,and sharp contradictions between architectural form and structure.In the structural design,the torsional force brought by the anti-torsional shape of the beam body is controlled by adjusting the cable force,and the circular bearing platform is used at the bridge tower to offset the torque.By reasonable arrangement of the span,the bridge stiffness is increased and the negative bending moment of the middle support is reduced.The pre-stressed group nail anchorage technology is adopted for the deck of steel-concrete composite beam,and special research is carried out for the comfort level of pedestrian bridge.Meanwhile,the structural measures of damper connection are reserved.The key technical problems and measures in the structural design of the cable-stayed bridge are introduced in this paper.