官新高速公路马路口资水大桥主梁方案比选

Selection of Main Girder Scheme for Malukou Zishui River Bridge on Guanzhuang-Xinhua Expressway

湖南官新高速公路马路口资水大桥主桥为主跨500 m的双塔双索面半飘浮体系斜拉桥,在该桥主梁设计时,提出了钢-UHPC组合梁(方案1)和钢-混组合梁(方案2)2种方案。为选择合理的主梁方案,对2种主梁对应的大桥结构方案进行设计,采用MIDAS Civil和ANSYS软件分别建立全桥和UHPC局部受力模型,分析2种方案的结构静力、动力性能,最后对2种方案的经济性进行比较分析。结果表明:2种方案的结构受力均能满足规范要求;与方案2相比,方案1的自重较小,可以明显降低其他结构部件工程量,其桥面板的抗裂性能好,建造成本可降低约3.3%。因此,该桥主梁推荐采用钢-UHPC组合梁方案进行设计。

The Malukou Zishui River Bridge on Guanzhuang-Xinhua Expressway in Hunan Province is a two-pylon cable-stayed bridge of a half-floating system.The bridge has a main span of 500 m and the stay cables are fanned out in double cable planes.During the design of the main girder,two schemes were considered,including the steel-UHPC composite girder(scheme 1)and the steel-concrete composite scheme(scheme 2).To select the rational main girder scheme,the bridge structures with the two types of main girders were designed,and the software MIDAS Civil and ANSYS were employed to build the model of the full bridge and the model of local load bearing details of the UHPC slabs.The static and dynamic performance of the two schemes was analyzed,and the economic benefits of the two schemes were compared and analyzed.The results show that the load bearing capacities of both two schemes can meet the code requirements.Compared with scheme 2,the self-weight of the structure in scheme 1 is smaller,which can remarkably reduce the construction work of other structural components.In addition,the anti-cracking performance of the deck slabs in scheme 1 is better and the construction costs can be cut down by about 3.3%.Therefore,the scheme of steel-UHPC composite girder was finally chosen.