既有多跨桥梁整体顶升安全技术研究与实施——以前锋涌大桥为例

Research on safety technique for existing multi-span bridges integrally jacking and its application-- take Qianfengyong bridge as an example

为解决既有桥梁净空不足的问题,避免桥梁拆除重建,开发整体顶升安全技术。以珠海市前锋涌大桥为例,确定顶升托换体系,将千斤顶沿桥轴线布置,先整体同步顶升,后逐墩台顶升,且梁体顶升高差控制在10 cm安全范围内;然后采用后锚固植筋加固、静力切割、微膨胀混凝土立柱连接加固和墩柱微错位处理等技术,解决多跨桥梁顶升安全施工中的原结构柱、梁加固和支柱打断、接高等难题。对顶升后桥梁承载力进行静载试验检测。结果表明,桥梁顶升完毕后,在设计荷载检测下梁体总挠度均在3.4 mm以内,其校验系数范围为0.7～0.8;各梁总应变在84με以内,其校验系数范围为0.8～0.9,承载能力满足安全运营要求。

To solve the problem of insufficien： clearance of some existing bridges, avoid their demolition and reconstruction, a safety technique for existing multi-span bridges integrally jacking was developed. Qianfengyong bridge was taken as an example. An underpining system was established. After jacking, a static loading test was made. The results show that total deflection of beam body is within 3.4 mm, with verification coefficient between 0.7 - 0.8, each beam total strain within 84 δε, and verification coefficient between 0. 8 - 0. 9, and that bearing capacity raeets the requirements of safety operation.