Numerical Simulation Technology Research On Steel-box Girder Incremental Launching Construction Of Liangji Canal Bridge

Using the incremental launching method, due to the forces of the construction phase and the operation phase are very different, and with the influence of construction machinery, we need to determine construction parameters such as the launching force and the length of the launching nose in the construction process, master the changes of the internal force, the deflection and the stress of every segment, control the impact on flexible pier in a allowable range. So far, there are already some researches on bridges constructed by incremental launching method, but there are few researches on the process of incremental launching construction of large steel-box girder.The thesis is under the background of Jining Taibai Building West Road Liangji canal bridge, which applied the the incremental launching method in the steel-box girder construction of main span and its longest span is 60 meters. Based on the finite element theory, the thesis uses MIDAS calculation software, firstly analyses the structural stress, deformation of the steel-box girder and the launching nose in the incremental launching construction process, finds out adverse conditions that may occur in the facets of structural stress, deformation and stability. Then according to those adverse conditions, builds up three-dimensional plate element model, do the finite element analysis of structural force and deformation. The aim is to botain the weak link of the key structures on strength, stiffness and stability, provide basis for the formulation of incremental launching force, launching nose length and the construction technology, meanwhile provide numerical backup of construction control. The distinguishing features of the thesis are as below:(1)Introduces the general development achievements of incremental launching menthod and the current research situation of construction emulation, discusses the construction emulation method and theory, analyses some important factors of construction emulation, provides theory basis for construction emulation.(2)Combines the project of Liangji canal bridge, brings in the technology of actavition/passivation, builds up two dimensional beam element model, imatates the construction process of steel-box girder incremental launching, analyses the stress of the main girder and the launching nose and the deformation of the launching nose front end, find out the most adverse conditions that may occur in the facets of structural stress, deformation and stability.(3) For the typical state of the construction phases, builds up three-dimensional plate element model using finite element software MIDAS, analyses the stress of the main girder, the deformation of the launching nose front end, partial stress concentration condition at the supporting place of the steel-box girder and the launching nose.(4)Analyses the stress and deformation of the lower structure such as the truss and the temporary pier.The results of simulation analysis show that the stress and deflection of the key structures such as the steel-box girder, the launching nose, the temporary pier and the incremental launching platform truss are within the allowable ranges, thus meet the construction requirements.The simulation analysis method, theory and technology adopted by the thesis can provide reference to the similar research hereafte. The outcome of the research enriches the current simulation content of steel-box girder incremental launching construction whole process.