UHPC加固在役大跨径悬索桥钢桥面:实桥试验与理论分析  

In-site Test and Theoretical Analysis of Innovative UHPC Strengthening Structure on Steel Deck of an In-service Long-span Suspension Bridge

作　　者：曹君辉[1,2] 杨碧川 邵旭东[1,2] 王洋[1,2] 李知强 CAO Junhui;YANG Bichuan;SHAO Xudong;WANG Yang;LI Zhiqiang(College of Civil Engineering,Hunan University,Changsha 410082,China;Hunan Provincial Key Laboratory for Wind and Bridge Engineering(Hunan University),Changsha 410082,China;Yichang Changjiang Highway Bridge Construction Development Company,Yichang 443004,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]风工程与桥梁工程湖南省重点实验室(湖南大学),湖南长沙410082 [3]宜昌长江大桥建设营运集团有限公司,湖北宜昌443004

出　　处：《湖南大学学报（自然科学版）》2023年第9期32-45,共14页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51978259);国家自然科学基金重点项目(52038003);湖南省科技创新计划资助项目(2021RC3068)。

摘　　要：为解决大跨径钢桥正交异性钢桥面板普遍存在的疲劳开裂且维修困难等问题,提出了一种疲劳裂缝可免修复的UHPC加固新结构.以一座在役大跨径悬索桥为研究对象,介绍了新结构的应用背景,并对大桥原沥青铺装、裸钢桥面、钢-UHPC轻型组合结构三种桥面状态分别开展了现场试验.基于试验结果,系统揭示了钢桥面4类典型疲劳细节的受力特性,包括应力分布规律和加固后的应力降幅,同时,对实桥建立了局部梁段有限元模型,模拟试验中的所有加载工况并进行了对比分析,发现计算得到的应力响应面与试验结果基本一致,最大误差约为10%.研究结果表明:对于每类疲劳细节,其在纯钢桥面和原沥青铺装两种状态下的应力基本无差异,表明原沥青铺装劣化严重,无法改善钢桥面的疲劳受力状态;而对比铺设UHPC前、后,钢面板上的疲劳细节应力降幅达41%~85%,其中,钢面板-U肋焊缝细节应力降幅为85%,顶部过焊孔处细节应力降幅为44%,而横隔板与U肋交叉部位细节应力降幅为41%,表明UHPC加固薄层有效提高了钢桥面的局部抗弯刚度,从而降低了车辆荷载作用下钢桥面的应力水平.此外,得到了钢桥面上不同疲劳细节的应力响应线,结果表明,各疲劳细节的应力响应因测点位置不同而存在一定差异.顶部过焊孔处细节横桥向压应力响应范围较小,而拉应力响应范围较大;面板及顶部过焊孔处细节的纵向应力响应线较短,而U肋-横隔板连接处细节的应力在3道横隔板或横肋范围内仍保持较高水平.To address the fatigue cracking issue and the resultant maintaining difficulties of orthotropic steel bridge decks(OSDs),which are common in long-span steel bridges,the research group at Hunan University proposed a new UHPC-based strengthening structure and with this strengthening technique,the fatigue cracks in OSDs can be exempt from repairing.Based on a long-span in-service suspension bridge as the research subject,this paper introduces the application background of the new strengthening technique,and presents a series of in-site experimental tests that were performed to reveal the response of the OSD under three states,i.e.,with original the asphalt overlay,with no overlay,and with a UHPC strengthening layer.The fatigue performance of four typical fatigue-prone details in the OSD was systematically revealed based on the test results,including the stress distribution as well as the stress reduction after strengthening.At the same time,a local finite-element(FE)model was established for the bridge and the load cases considered in the experimental tests were simulated in the FE model.It was found that the stress response surfaces of the fatigue-prone details are basically consistent with the corresponding test results,and the maximum difference is about 10%.The research results show that for each fatigue-prone detail,the stresses exhibit no significant differences under two states,i.e.,with the original asphalt overlay and without overlay,indicating that the original asphalt overlay deteriorated seriously and could not effectively improve the mechanical state of the OSD.The stresses of the fatigue-prone detail were reduced by 41%~85% when the OSD was strengthened by a thin UHPC layer.For the fatigue-prone detail of the U rib-to-deck plate welded connection,the stresses were reduced by 85%,while for the fatigue-prone details at the upper cutouts and at the intersections between the U rib and diaphragm,the stresses reductions were revealed as 44% and 41%,respectively.This confirms that the thin UHPC layer could si

关 键 词：大跨径钢桥 疲劳应力 实桥试验 正交异性钢桥面板 轻型组合桥面 有限元分析 应力响应面 

分 类 号：U443.33[建筑科学—桥梁与隧道工程]