正交异性钢桥面板足尺模型疲劳试验

Fatigue experimental study of a full-scale steel orthotropic deck model

20世纪90年代后,正交异性钢桥面板在我国斜拉桥、悬索桥等大跨公路桥梁建设中得到广泛的应用。然而,由于受设计、制造水平所限以及越来越大的交通荷载影响,多座钢桥在运营10年左右即出现了较严重的正交异性钢桥面板疲劳病害,大大影响了钢桥的安全性及耐久性。为此开展正交异性钢桥面板足尺模型疲劳试验研究,模型纵向为1.0m+3.5m+1.0m的三跨结构,横向宽度3.0m,包括5个U型纵肋。模型所采用的结构形式、制造工艺、边界条件反映了我国大跨钢桥常用的扁平钢箱梁使用现状,另外在U肋-横梁交叉处采用几种新型构造。试验总计完成600万次常幅疲劳加载,试验结束时在U肋嵌补段对接接头处发现肉眼可见的疲劳裂纹。以测点应力突变作为疲劳敏感部位疲劳失效的准则,采用距离焊趾10mm处的测点应力作为参考应力,U肋嵌补段对接接头、与U肋焊接处的顶板疲劳强度等级均相当于欧洲规范Eurocode中的71类细节。

Since the 1990s, steel orthotropic decks have been widely utilized for long-span bridges such as cable-stayed bridges and suspension bridges in China. However, due to the early design and manufacture level and increasing traffic loads, serious orthotropic decks fatigue cracks that will low the safety and durability emerge in several bridges after about ten years of service time a. Fatigue tests were conducted a steel 1. 0m ＋ 3. 5m ＋ 1. 0m span 3. 0m-wide full-scale orthotropic deck with five U -shaped ribs The model are constructed according to the same structure styles, manufacturing processes and boundary conditions used in the common flat steel box girders in China. Additionally, several novel rib-tocrossbeam joints are incorporated into the panel. After six million fatigue cycles, fatigue cracks were found at the rib butt-welded splice joints. Based on the failure criteria of the sudden change measured stresses with a, it is confirmed that the fatigue strengths of rib butt-welded splice joints and rib-to-deck plate welded joints with deckplate failure are similar to design category 71 in the Eurocode when the the measured stresses at a distance of ten millimeters from the weld toe are used.