Key Technologies of Whole Incremental Launching Construction Control for Inclined Continuous Box Girder with Steep Longitudinal Gradient

Abstract

Under the background of Liuyang River Bridge, systematical studies of the key technologies of incremental launching control for inclined continuous box-beam bridge are of important theoretical significance and practical engineering value, with the features of incremental launching construction control difficulties caused by vertical curve, skew, steep longitudinal gradient, and with cantilever flange and heavy box girder. The results show that the limitation of dead weight of box girder can be overcome by precast supporting system composed of box-girder precast bearing system and box-girder incremental launching bearing system. The factors of stiffness and weight of main girder should be considered for guiding beam configuration in incremental launching construction, which should choose reasonable stiffness, length and weight, to assure that the negative moment peak of largest cantilever status and a status when guiding beam is on the pier is consistent with the largest fulcrum negative moment during the use state. The predictive value and measured value of stress and deformation of whole process of steep longitudinal gradient incremental launching about inclined continuous box beam are in good agreement. Horizontal traction force of jack, transverse offset of box beam and stress of temporary pier are all be well controlled, satisfying all design requirements, which means that simulation analysis and control of whole process of incremental launching is effective and feasible. The study results offer reference for similar bridges about the whole process of incremental launching construction.