卸载程度对钢桁梁桥主桁构件加固效果的影响  

INFLUENCE OF UNLOADING DEGREES ON THE STRENGTHENING EFFECT OF THE MAIN TRUSS MEMBERS OF STEEL TRUSS GIRDER BRIDGES

作　　者：苏庆田[1] 王思哲 薛智波 张春雷 王倩 陈亮 SU Qing-tian;WANG Si-zhe;XUE Zhi-bo;ZHANG Chun-lei;WANG Qian;CHEN Liang(Department of Bridge Engineering, Tongji University, Shanghai 200092, China;Shanghai Municipal Engineering Design Research Institute (Group) Co., Ltd, Shanghai 200092, China)

机构地区：[1]同济大学桥梁工程系,上海200092 [2]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《工程力学》2019年第B06期92-97,105,共7页Engineering Mechanics

基　　金：国家“973”重点基础研究发展计划项目(2013CB036303)

摘　　要：早期修建的部分钢桁梁桥已无法满足当前通行能力的要求,需要对原桥主桁进行加固。桥梁加固通常是在负载情况下进行,需要考虑加固构件的分阶段受力,不同的加固施工方案所对应的卸载程度会产生不同的加固效果。该文结合松浦大桥扩宽加固工程,利用ANSYS单元生死技术模拟加固施工过程,提出了能够考虑加固板件应变滞后的有限元模拟方法。分别计算新旧构件在三种不同卸载程度的加固方案下的应力分布,从构件安全度及材料利用率两方面分析卸载程度对加固效果的影响。最后综合考虑社会影响比选施工方案。结果表明:所提出的构件加固模拟方法能有效考虑应变滞后效应并实现杆件的加固模拟;加固构件安全度和加固材料利用率随着卸载程度的增加而提高;综合社会经济性影响,推荐采用先更换下层桥面,再拆除上层桥面,然后加固主桁结构,最后安装新的上层桥面的施工方案。Some early-built steel truss bridges can no longer meet the requirements of current traffic capacity, so it is necessary to reinforce the main trusses of the original bridges. Bridge reinforcement is usually carried out under load. It is necessary to consider the phased forces of the reinforcement members. The different degrees of unloading corresponding to different reinforcement construction schemes will produce different reinforcement effects. In this paper, based on the reinforcement and reconstruction project of the Songpu Bridge, the element birth and death technology of ANSYS is used to simulate the strengthening construction process. A finite element simulation method considering the strain lag of the reinforced plates is proposed. The stress distributions of the old and new members under three different reinforcement schemes corresponding to different degrees of unloading are calculated. The influence of unloading degrees on the reinforcement effect is analyzed in terms of component safety and material utilization efficiency. The comparison and selection of construction schemes are carried out considering the social impact. The results demonstrate that the proposed component reinforcement simulation method can effectively consider the strain lag effect and is convenient to simulate the reinforcement of truss members. Safety degrees of reinforced members and utilization ratios of reinforced materials increase with the increase of the unloading degree. Considering the social impact, it is recommended to adopt the construction scheme which replaces the lower deck first, removes the upper deck, then reinforces the main truss structure and finally installs a new upper deck.

关 键 词：钢桁梁桥 钢桥加固 卸载程度 应变滞后 增大截面法 加固模拟方法 

分 类 号：U445.7[建筑科学—桥梁与隧道工程]