大跨度空腹式箱形拱桥施工技术研究

Study on Construction Technology of Long-span Hollow Box Arch Bridge

海东大道三号桥位于青海省海东市乐都区,桥梁全长117m,结构形式为上承空腹式箱形拱桥,跨径为单跨80m,拱轴线采用悬链线。本文介绍了上承空腹式箱形拱桥的施工工艺流程,对支架基础处理、支架搭设、支架受力检算、支架预压及支架的卸落进行了系统地分析与研究,对主拱模板制作及安装工艺、混凝土的浇筑方案进行了充分地论证分析。通过后浇带的设置,减小了混凝土收缩和支架变形对主拱结构受力的影响,而支架分次卸落防止了落架时拱圈的拉应力偏大和支架的失稳破坏。

The No. 3 Bridge of Haidong Avenue is located in Ledu District, Haidong City, Qinghai Province, with a total length of 117 meters. The structure of the bridge is a top-supported hollow box arch bridge with a span of 80 meters. The arch axis adopts catenary line. This paper introduces the construction process of upper-supported hollow box arch bridge, systematically analyzes and studies the bracket foundation treatment, bracket erection, bracket stress checking, bracket preloading and bracket unloading, and fully demonstrates the fabrication and installation technology of main arch formwork and concrete pouring scheme. The influence of concrete shrinkage and bracket deformation on the stress of main arch structure is reduced by setting the post-pouring band. Meanwhile, the multi-stage unloading of the bracket prevents the arch ring from large tension stress and the instability of the support.