Abstract:Caihong Bridge in North Third Ring Expressway of Zhengzhou spans the largest railway marshalling yard in Asia and is composed of four-spans independent simple-supported concrete-filled steel tube curved chord truss beam bridge. Its span arrangement is 122 m + 62 m + 62 m + 122 m. The bridge is evaluated as a Class IV dangerous bridge. Due to the bridge spanning the upper departure throat area (7 tracks) and the locomotive return section (6 tracks) of Zhengzhou North Marshalling Yard at the west side, and at the east side spanning the lower arrival throat area (4 tracks), and no railway access under the two spans in the middle, a scheme for the removal of the bridge from its original location through longitudinal incremental launching + transverse sliding is proposed. After the reinforcement of the original structures, a composite joint continuous incremental launching method of “walking incremental launching device + slider with pushing force” is proposed. The results show that during the girder movement, the stress state of the bridge is adjusted in real time by using the multiple sets of “walking incremental launching device + slider with pushing force”. After the reinforcement by adding new members and increasing the cross-section of existing members, the steel truss beams of the old bridge have always been in a safe and reliable state during the longitudinal displacement and incremental launching construction process, which provides practical reference for the bridge demolishing projects under the complex construction conditions.
