摘要
桥梁伸缩缝受车辆荷载的长期冲击易发生疲劳破坏,且维修更换困难,目前关于模数式伸缩缝尤其是中梁钢焊接点疲劳损伤寿命的研究较少.文中以某大桥SD-160模数式伸缩缝损坏更换为例,通过车辆荷载调查分析,建立了5种简化车辆荷载频值谱;采用ANSYS有限元软件结合Miner疲劳累积损伤理论估算SD-160型模数式伸缩缝锚固区混凝土、锚固钢筋与预埋钢筋焊接点以及伸缩缝中梁钢的疲劳寿命.结果表明:锚固区混凝土使用寿命为7.7年,中梁钢在只考虑车辆载荷作用时的使用寿命为29.3年,预埋钢筋焊接点为10.7年;支撑横梁间距越大,中梁钢的使用寿命越小;锚固区混凝土强度增大,混凝土本身和预埋钢筋焊接点的使用寿命都随之增大;弹性树脂混凝土的使用寿命约为C50混凝土的2倍;按大桥SD-160伸缩缝更换方案,中梁钢焊接点估算使用寿命为6.2年,建议方案Ⅰ为7.7年,方案Ⅱ为20.8年.文中研究成果可供类似伸缩缝的设计和维修更换借鉴.
Long-term impacts due to traffic loads may result in the fatigue damage of bridge expansion joints that is difficult to repair and replace. However,there are few researches on the fatigue lifetime of modular expansion joints,especially for the middle-steel beam-welded points. In order to solve this problem,the damage and replacement process of the SD-160 modular expansion joints of a bridge is taken as an example and a survey of the bridge traffic load is performed,based on which five different types of simplified vehicle load frequency spectrum are established. Then,the ANSYS finite element software and the Miner fatigue cumulative damage theory are used to estimate the fatigue lifetime of the SD-160 modular expansion joints in the anchorage concrete,the welding points between anchored and pre-embedded bars,as well as the middle welded steel beam. The results show that( 1) the lifetimes of the anchorage concrete,the middle steel beam only considering the vehicle load and the welding points of embedded bars are respectively 7. 7,29. 3 and 10. 7 years;( 2) with the increase of the space between two supporting beams,the lifetime of the middle steel beam decreases;( 3) greater strength of the concrete in the anchorage zone helps to prolong the lifetime of the concrete itself and the welding points between anchored and pre-embedded bars;( 4) the lifetime of elastic resin concrete is about 2 times that of C50 concrete; and( 5) according to the replacement program of the SD-160 expansion joints,the simulated lifetime of the welded points in the middle steel beam is 6. 2 years,and the service lifetimes of programs Ⅰ and Ⅱ are respectively 7. 7 and 20. 8 years. This research provides a reference for the design and replacement of the expansion joints similar to the investigated one.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2016年第4期91-100,共10页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金青年科学基金资助项目(51508204)
广东省公路管理局科技项目(粤公研2009-14)~~
关键词
桥梁
伸缩缝
疲劳损伤
疲劳寿命
bridge
expansion joint
fatigue damage
fatigue lifetime
