The Beam-Arch Synchronous Construction Method For 220m Handle-basket Arch Bridge

In recent years, with the rapid advance of urbanization, not only urban traffic congestion has increasingly been put into the spotlight, but urban rail transit ushered in the era of rapid development. Currently, urban rail transit construction in first and second tier cities is in full swing, while that in third and fourth tier cities is in plan or under construction. Due to its rapid construction speed and relatively low cost, light rail is the prior choice of suburban rail transit.The thesis focuses on the 220m steel box handle-basket arch bridge in the first-stage project of Ningbo Rail Transit Linel. The bridge is located on two curves, with a span of 220 meters and vector height of 44 meters. Its girder in plane is broadening special-shaped beam: midspan has lineal layout with girder of same width, while sidespan shows curve layout with broadening girder. The width of beam top for the midspan is 19.4m; the width of main girder at arch foot is 21.83m; that of main girder top of beam end for left sidespan is 18.352 m;and that of main girder top of beam end for right sidespan is 18.846m. The cross dip of two pieces of arch ribs is 6°; the arch rib spacing is 8.486m; and the arch foot spacing is 17.685 in. The inside width of arch rib is 2.4m, with height changing gradually along the direction of arch rib.The inside height of vault is 2.5, and that of arch foot is 6.5m. There is a small bevel angle between the beam and Ningbo expressway. Moreover, the construction was far behind schedule due to the influence of the requisition and demolishing. To ensure duly open to traffic, the beam-arch synchronous construction method was carried out, which yielded good results and provided favorable technical support and references for similar bridge construction in the future.1. Having analyzed construction environment and stress, the paper researches the optimization of arch rib sections on the basis of guaranteeing stress and reducing construction difficulties.2. The paper studies the beam-arch synchronous construction method, where the reinforced concrete tie beam construction and arch rib assembling are conducted simultaneously. It greatly shortens the construction period by six months (The original duration was estimated as 18 months by building beam and arch in sequence).3. By detailed calculation, the interaction among support foundations during beam-arch synchronous construction is overcome, which ensures that beam body, arch rib support force and settlement meet the design requirements.