襄阳市东西轴线二跨汉江大桥钢-混组合桥面铺装受力分析

Mechanical Performance of Steel-Concrete Composite Deck Pavement in Second Hanjiang River Bridge on East-West Axis of Xiangyang City

襄阳市东西轴线二跨汉江大桥主桥为(3×60+320) m的独塔混合梁斜拉桥,边跨主梁采用混凝土梁,主跨主梁采用钢箱梁,桥面采用14 mm厚正交异性钢桥面板+80 mm厚C40聚丙烯纤维混凝土+70 mm厚SMA改性沥青混凝土的铺装方案。为分析该钢-混组合桥面铺装方案的结构受力是否合理,采用MIDAS Civil 2010软件建立全桥整体模型及横隔梁、U肋局部分析模型,对钢梁、混凝土桥面板的应力及混凝土桥面板的裂缝宽度进行计算分析。结果表明:钢梁及混凝土桥面板的各项应力均在规范容许的范围内;钢梁的Von Mises等效应力小于钢材的屈服强度;混凝土桥面板的表面最大裂缝宽度为0.097 mm,小于规范控制的目标值0.15 mm。

The main bridge of the Second Hanjiang River Bridge on the east-west axis of Xiangyang City is a single-span hybrid girder cable-stayed bridge with spans of 3×60 m and 320 m. The main girders in the side spans are the concrete girders, while the main girders in the main span are the steel box girders. The deck system consists of 14 mm-thick orthotropic steel deck plates, 80 mm-thick C40 polypropylene fiber concrete and 70 mm-thick SMA modified asphalt concrete. To examine the rationality of the mechanical performance of the steel-concrete deck pavement, the MIDAS Civil 2010 software was used to establish the integral model of the overall bridge and the models for local analysis of the diaphragms and U-ribs. The stresses in the steel girders and concrete deck slabs as well as the width of cracks in the concrete deck slabs were calculated and analyzed. The results show that the stresses in the steel girders and the concrete deck slabs are all within the range of allowable values prescribed in the specifications. The Von Misses stresses of the steel girders are smaller than the limit values of the yielding strength of the steel. And the maximum width of cracks on the surface of concrete deck slabs is 0.097 mm, which is far less than the target value of 0.15 mm suggested in the specifications.