Multi-span Moveable Formework Cast-in-place Box Girder Study Technology

In order to solve construction for Cast-in-place concrete box girder at complex geographical position, such as mountain area and deep cliff area in Chongqing or the West of China, in order to use the new technology and the new equipment properly, the article introduces the continuous box beam of Shi jia liang interchange in Chongqing Ring Expressway, it’s building technologies uses multi-span and folded-type structure moveable formwork, compares strengths and weaknesses of cast-in-place box girder at home and abroad in detail, takes the trestle platform constituted by standardized beret pieces to support Cast-in-place concrete box girder, sets up bearing trussing system under the horizontal beret beam to supply stiffness and bending resistance for the trestle platform, installs the locomotive wheel at vertical and horizontal transverse direction under the beret beam to move easily, it improves efficiency of construction vastly and settles the great difficulty of construction for Cast-in-place continuous box Girder at complex geographical position, it is worth using widely due to advanced technology、low cost and easy work..Multi-span moveable formwork is studied based on single-span folded-type structure moveable formwork and multi-span high piers bridge of Shi jia liang interchange in Chongqing Ring Expressway, success in changing strengthen inverted triangle to strengthen inverted trapezoidal for long-span box girder, also success in accommodating various-span platform、various-supporting point position、various distance of pier column with platform supporting system、various width of platform、pre-camber of curved bridge, at the same time, studies the technology of setting up cross-slope and grade, makes a low cost、advanced technology、guaranteed quality、security、ahead of schedule construction program, gathers the construction experience for the same kinds of bridge.The work method is better than traditional full support method and temporary pier method in economy and technology, it is used in Shi jia liang Interchange successfully, shorten the time limit for the project greatly, it is well received by all sectors of the community at quality、security、time、environmental protection etc, it also gets good economic effectiveness and social benefits.