姚响宇 李真兴

摘要：荷载试验是评定桥梁承载能力及安全性最直接和最有效的办法。通过建立钢桁架人行天桥的有限元模型，分析了桥梁在设计人群荷载下的静力特性，同时进行了模态分析。通过荷载试验，实际测量了桥梁控制截面的应变和挠度。试验研究表明，桥梁实测应变和挠度都低于理论值，试验荷载效率、校验系数和残值比等指标均满足城市桥梁检测技术标准的要求，试验桥跨在力学性能上满足设计和使用的要求。

关键词：荷载试验；有限元；校验系数；

中图分类号：U441.6文献标识码：A

Load testing research of cities steel truss footbridge

Yao XiangyuLi Zhenxing

(1.Guangzhou Construction Quality and Safety Testing Center, Guangzhou 510699, China; 1.Guangzhou Cheng An Bridge Testing Ltd, Guangzhou 510420, China)

Abstract: Load testing is a bridge carrying capacity and safety of the most direct and effective way to assess. The finite element model of steel truss footbridge was established, static characteristics of the bridge was analyzed under the load of the crowd, simultaneously the modal analysis was conducted. By loading test, the strain and deflection of bridge control section was measured. The research had shown that bridges measured strain and deflection were lower than the theoretical value, test load efficiency, calibration factor and residual value ratio meet the city's bridge inspection technology standards, the bridge meet the requirements of designing and using on the mechanical properties.

Keywords: load testing; finite element; calibration coefficient

E-mail：1515252297@qq.com

引言[作者简介：姚响宇，男，硕士。

收稿日期：2014-03]

钢桁架桥在铁路中应用较多，而在公路及城市桥梁领域很少见到。但是在公路和城市桥梁领域选用钢桁架桥有其独特的优越性，施工速度快，对交通影响较小，桥型美观。由于钢桁架桥有以上优点，又伴随着我国城镇化发展的契机，有越来越多的钢桁架桥被应用于城市建设中。

本文主要介绍位于广州市罗冲围公交总站钢桁架人行天桥的力学特性，并通过荷载试验和有限元计算对该桥承载力和动力特性进行评定。

连续钢桁架人行天桥概述

该天桥上部结构为三跨连续钢桁架，下部结构边墩、中墩采用钢筋砼双柱式墩。该桥计算跨径为18.6+29.92+22.361米，主桥净宽为3.5m，总宽为5m。钢桁架主要采用Q345C钢材，主墩、楼梯、楼梯墩采用C30混凝土。该桥荷载标准：主桥人群荷载按4.0kPa计。钢桁架人行天桥成桥模型如图1所示。

图1钢桁架人行天桥