郑杰

摘要：针对某桥梁病害失效问题，对桥梁的外观和材质情况进行检测，对拟更换T梁处的盖梁结构进行安全评估。根据理论分析结果确定盖梁测点布置和加载工况，通过载荷试验分析偏载工况和正载工况下盖梁结构的挠度和应变结果。理论分析和试验结果均表明，该桥跨实际承载能力仍满足正常承载要求，可继续使用。

关键词：桥梁; 盖梁; 载荷试验; 承载能力; 挠度; 应变

中图分类号：U448.213; TP202.1

文献标志码：B

Bearing capacity evaluation on bridge capping beam

based on load test

ZHENG Jie

（Zhengzhou Highway Administration Bureau Zhengzhou 450015 China）

Abstract：

As toa bridge failure problem the appearance and material condition of the bridge is checked and the safety assessment of cover beam structure at the location of T beam which is planned to be replaced is carried out. Based on the theoretical analysis results the layout of measuring points and loading conditions of capping beam are determined. The deflection and strain results of the capping beam structure under unbalanced load and normal load conditions are analyzed by load test. Both theoretical analysis and experimental results show that the actual bearing capacity of the bridge span still meets the normal bearing requirements and the capping beam can go on active service.

Key words：

bridge; capping beam; load test; bearing capacity; deflection; strain

0 引 言

某公路桥梁位于G207国道上，设计载荷等级为I级，由于T梁病害较严重，拟对上部梁板结构进行更换。为确定更换方法，对盖梁性能进行分析，验证盖梁在当前状态下的承载能力和使用性能。

该桥梁左右幅设置，全长为84.50 m，单幅宽为8.00 m，右幅上部结构为4×20.00 m T梁，先简支后连续结构，单跨为7片。桥梁下部为桩柱式墩台，桥墩均采用普通板式橡胶支座，桥台采用四氟滑板式橡胶支座，采用D80伸缩缝，桥梁结构示意见图1。

20.00 m小箱梁梁高1.20 m，原T梁的梁高为1.30 m，高度较为接近，故初步设计将原T梁更换为小箱梁，同时根据最新规范要求，两侧加装防撞护栏。因为小箱梁结构质量比原T梁结构质量大，所以对桥墩和盖梁的承载要求更高。桥墩结构在服役过程中未发现明显沉降和偏移，可考虑1.25倍的承载能力提高量，满足承载要求，因此本文仅对盖梁性能进行分析。[13]

1 外观检测和标度评定

为在模拟过程中充分体现结构的服役状态和材质变化对结构参数的影响，对桥梁外观质量和材质状况进行分析。……