关键词: 桥梁工程；钢管混凝土拱桥；拱铰；斜腹杆；合理夹角；理想桁架；三角刚架

Abstract: The steel tubular arch segments of concrete filled steel tubular (CFST) arch bridge were usually constructed by cantilevering assembly method with cable hoisting. In order to adjust the installation alignments of arch rib, temporary arch hinge was often set at the springing. The arch hinge structures were simplified as the ideal truss and the rigid frame structure respectively. Firstly, according to the balance principle of force system, the consistent expression of the axial force of the diagonal web member of the ideal truss was derived. The ratio of the Euler critical load to the axial force was defined as the stability coefficient of the web member, the relationship between the stability coefficient and the angle between the web member was established, and the angle value corresponding to the maximum stability coefficient of the web member was obtained. Secondly, based on the principle of force method, the calculation expressions of moment and axial force at the end of triangular rigid frame were derived. The correctness of the calculation formula was verified by a calculation example. On this basis, the change law of the angle between the internal force of arch hinged rigid frame and diagonal web member was further studied. According to the structural requirements of the code for design of highway concrete filled steel tubular arch bridge that the angle between the main and branch pipes should not be less than 30°, it is concluded that the angle between the diagonal web members of arch hinge is more reasonable between 60° and 100°, which verifies the rationality of the arch hinge structural design of some built CFST arch bridges in China.

Key words: bridge engineering; concrete filled steel tubular arch bridge; arch hinge; diagonal web member; reasonable angle; ideal truss; triangular rigid frame