Abstract: Variable section arch ribs are often used in long-span concrete filled steel tubular (CFST) arch bridge to meet the mechanics demands.Focusing on the variable section height design of steel tube arch rib, the generalized Ritter formula was derived based on the Ritter formula, which was applied to the trial design of a 700m span concrete filled steel tube arch bridge.The internal forces, elastic stability, dynamic characteristics and main arch stiffness of steel tube arch under different parabola times were calculated.The analysis results show that all the main parameters can meet the specification requirements.Compared with the Ritter formula, the variable section steel tube arch designed by the generalized Ritter formula makes the axial force distribution of the upper and lower chords more uniform, because the negative bending moment of the arch foot section is reduced.

Key words: bridge engineering; concrete filled steel tubular arch bridge; Ritter formula; generalized Ritter formula; variable section height; trial design

摘要： 大跨度钢管混凝土拱桥常采用变截面拱肋，以满足受力需要。围绕钢管拱肋变截面高度设计，在李特公式基础上推导了广义李特公式，将其应用于一座700 m跨钢管混凝土拱桥试设计中，开展了不同抛物线次数下钢管拱内力、弹性稳定、动力特性及主拱刚度的计算。分析结果表明：主要参数均能满足规范要求；相比于李特公式，采用广义李特公式设计的变截面钢管拱，由于减小了拱脚截面负弯矩，使截面上、下弦管的轴向力分布更趋均匀。

关键词: 桥梁工程；钢管混凝土拱桥；李特公式；广义李特公式；变截面高度；试设计