变截面劲性骨架钢筋混凝土拱桥外包混凝土过程中的线形控制方法

An Alignment Control Method for CFST Framed Arch Bridge with Variable Cross-section during Pouring Externally Wrapped Concrete

为研究变截面劲性骨架混凝土拱桥外包混凝土过程中的线形控制方法,以在建广安官盛渠江大桥为例,采用Midas/Civil建立影响线加载模型,利用软件的移动荷载功能,得到拱顶挠度影响线。然后运用MATLAB中的函数拟合功能,利用4阶傅里叶级数对得到的挠度影响线进行拟合,从而建立数学模型。对比分析了有未计入混凝土重量变化的拱顶挠度影响线,结果表明变截面拱较等截面拱在浇注外包混凝土过程中拱顶更易出现向上变形。基于影响线理论及叠加原理,推导了变截面劲性骨架拱桥在浇注外包混凝土过程中拱顶挠度的表达式,并提出若ω=∫L/20f(x)dx>0,则不能通过传统平衡浇注法来控制拱顶不出现向上变形的判断准则。最后推导了拱顶压重法和斜拉扣索法的计算公式,并利用Midas/Civil建模分析验证了计算公式的准确性。

To study the alignment control method for concrete-filled steel tube （CFST） framed arch bridge with variable cross-section during pouring externally wrapped concrete, taking Guang＇an Guansheng Qujiang Bridge under construction for example, the influence line loading model is built by Midas/Civil, and the influence line of deflection at vault is obtained by the software＇s function of moving load. Then, the influence line is fitted by using the function fitting function in MATLAB and the fourth order Fourier series, thus the mathematical model is built. Then, the influence lines of deflection at vault with and without considering the variation of concrete weigh is compared. The result shows that the upward deformation at vault of variable cross-sectioned arch is easier happened than that of constant sectioned arch. The expression of deflection at vault of SFST framed arch bridge with variable cross-section during pouring externally wrapped concrete is derived based on the theory of influence line and superposition principle. The judgment criterion that it cannot keep the vault deflection lying below the initial value through the traditional balanced pouring method if ω=∫0^L/2f（x）dx〉0. The formula of ＂the method of loading on vault＂ and ＂the method of cable-stayed buckling＂ is derived and is verified by Midas/Civil modeling and analyzing.