Study and Design of Continuous Groove Beam Arch Bridge of Jinan-Qingdao Passenger Dedicated Line

Research purposes: When the high-speed railway crosses over the urban overpass road and expressway, in order not to affect the normal passage of the lower road, reduce the construction height of the railway embankment, reduce the engineering cost, and meet the design requirements, it can adopt the continuous trough beam-arch structure with lower building height. On the (66.5+142+66.5) m continuous groove beam-arch bridge across Qingdao-Lanzhou Expressway in the newly built Jinan-Qingdao passenger dedicated line project, the main technical characteristics of this kind of structure are mastered by studying the design of main parameters such as structural size, stiffness of beam-arch, longitudinal and transverse force behavior and shear lag. Research conclusions:(1) The bridge deck layout is quite flexible, and the bridge deck width can be minimized by optimizing the layout of pavements and cable grooves. Appropriately increasing the width of side girders, setting up horseshoe structure and partial perforation of arch rib embedded section can effectively solve the problem of insufficient space for steel bundle layout caused by arch foot structure. (2) The arch axis, arch rib section form and suspender arrangement are similar to those of the conventional box-section prestressed concrete continuous beam arch, which can be taken as reference in design. The stiffness ratio of beam to arch mainly affects the internal force, residual creep and suspender force. The stiffness ratio is determined to be 36.0, and the internal force index of beam and arch rib is maintained at a reasonable level. (3) The analysis of shear lag shows that the shear lag coefficients of typical sections in side fulcrum, side span, middle fulcrum and mid-span are 1.29, 1.19, 1.30 and 1.14, respectively, which are larger than the standard calculation values of conventional box section. In order to ensure structural safety, the shear lag coefficients calculated based on solid model should be adopted in the design of trough beam arch. (4) At present, the continuous trough beam-arch bridge is seldom used in high-speed railway project and lacks certain design theory and experience. The research results can provide important reference for the design of similar bridges. © 2019, Editorial Department of Journal of Railway Engineering Society. All right reserved.