大角度倾斜桥塔爬模施工分析

Construction Analysis of Climbing Formwork for Large Angle Inclined Bridge Pylon

无背索斜拉桥多采用大倾角斜桥塔,使用爬模施工时存在仰面受力过大,成品直塔爬模施工系统存在无法直接使用的问题,以某无背索斜拉桥桥塔施工为例,提出将传统液压爬模模板横背楞处与劲性骨架增设拉杆拉结,并利用混凝土凝结过程侧压力减小特性,以小时距分次间断浇筑混凝土的施工方法,即“1次立模,2层浇筑”工艺,对此施工工艺以及将液压爬模模板横背楞处与劲性骨架拉结的构造方式进行计算分析。结果表明,劲性骨架能有效分担爬架仰面压力,爬架及模板背楞的受力与变形均满足规范要求。施工过程中实现了较大的塔柱分段浇筑高度,解决了斜塔爬模施工时存在的受力安全问题,且能缩短工期,降低工费。

Cable-stayed bridge without back cable mostly adopts the inclined bridge tower with large inclination angle.When the climbing formwork is used for construction,there is a problem that the upward force is too large,and the finished straight tower climbing formwork construction system cannot be used directly.Taking the construction of a cable-stayed bridge tower without back cable as an example,it is put forward to add tie rods at the transverse back edge of the traditional hydraulic climbing formwork and the rigid skeleton,and use the characteristics of reduction of the lateral pressure in the process of concrete setting,the construction method of pouring concrete intermittently at hourly intervals is the process of"one-time formwork erection and two-layer pouring".The construction technology and the structure mode of connecting the horizontal back edge of the hydraulic climbing formwork with the rigid skeleton are calculated and analyzed.The results show that the rigid skeleton can effectively share the vertical pressure of the climbing frame,and the stress and deformation of the climbing frame and the formwork back edge meet the specification requirements.In the construction process,the large segmental pouring height of tower column is realized,the stress safety problem existing in the climbing formwork construction of inclined tower is solved,and the construction period can be shortened and the labor cost can be decreased.