A形斜塔不等跨斜拉桥施工关键技术研究

RESEARCH ON KEY CONSTRUCTION TECHNOLOGIES FOR A-TYPE UNEQUAL SPAN CABLED BRIDGES WITH DIAGONAL TOWERS

毕节市倒天河某新建桥设计为半漂浮体系的A形斜塔不等跨斜拉桥,该桥为典型的市政景观桥梁。该类型桥塔在施工阶段均处于大偏心、长悬臂状态,塔底应力与塔端位移极其敏感,施工过程如何确保塔身应力不超限、线形不超标等问题为主塔施工的重难点。施工借助midas Civil有限元软件模拟计算,阐明了一次张拉成桥方案的可行性,并根据计算结果预判主梁现浇支架受力增大的情况,对施工具有指导意义。除此,仿真计算结果可获取各施工阶段的变形与应力参数,结合实时监控数据对各施工阶段进行了指导与纠偏,确保各构件的结构安全和线形要求,成桥索力与设计高度吻合,效果较好。

A newly built bridge in Daotian River,Bijie City is designed as a semi floating A-shaped inclined tower cable-stayed bridge with unequal spans.The bridge is a typical municipal landscape bridge.This type of bridge tower is in a large eccentricity and long cantilever state during the construction stage,and the stress at the bottom of the tower is extremely sensitive to the displacement at the end of the tower.How to ensure that the stress on the tower body does not exceed the limit and the linearity does not exceed the limit during the construction process has become a key and difficult problem in the main tower construction.The construction was simulated using midas Civil finite element software,and the feasibility of a one-time tensioning bridge scheme was elucidated.Based on the calculation results,it was predicted that the stress on the cast-in-place support of the main beam would increase,which has guiding significance for construction.In addition,the simulation calculation results can obtain the deformation and stress parameters of each construction stage.Combined with real-time monitoring data,guidance and correction are provided for each construction stage to ensure the structural safety and linear requirements of each component.The bridge cable force matches the design height,and the effect is good.