Research On Key Technology In The Kunming Crossing Railway Bridge About Walking Incremental Launching Construction

The method of walking incremental launching construction is a new technology inrecent years, adopting walking incremental launching device, its functions include jack-up,translation, lateral deviation, its functions include jack-up, translation, lateral deviation.Incremental launching devices are placed on temporary pier and mutually independentsupporting girder, no longer as traditional drag pusher in the process of incrementallaunching construction. In addition, the sliding surface in the inside of device and nolonger at the bottom of main girder and it can effectively ensuring the contact of thedevice and the main structure, improving the stress of the main structure and do notharm the main structure. This method can easily ensure the pre-cambering curve throughthe temporary block which on the device. At present, the research used on the newtechnology is insufficiency in the domestic and overseas, it is necessary to research somekey technologies of steel girder bridge in the process of incremental launching.This paper taking construction of steel groove girders of Nankun crossing railwaybridge as a research background, some key technologies about walking incrementallaunching construction under study. The main research contents as follows:（1）Detailed study the construction principle, walking incremental launching deviceand the process of construction technology and worked out the detailed and feasibleconstruction scheme.（2）Applying major finite element software ANSYS, establishing the FEM elementmodel, in order to analyze the structural behavior of the steel groove girder during theincremental launching construction stage, studying a relatively reasonable structure.（3）In order to get the local stress behavior of the steel groove girder on theincremental launching pier, establishing local entity finite element model of the steelgroove girder, the calculated results showed the rubber width and elasticity modulus ofrubber and corner stiffer can ameliorate the stress state of steel groove girder. The FEMmodel based on contact element was created to simulate the friction force between thegirder and the incremental launching device by using the results of the overall analysis andstudying a reasonable local stress structure.（4）In order to establish a solid foundation for the construction, we do someexperimental studies about walking incremental launching device which including themaximum top lift,synchronization performance of horizontal pushing and vertical pusher.（5）Studying the main content of construction control and sensitivity calculating theadjustment of the elevation in the process of incremental launching construction. Finally,proving the validity of the adjustment method of the elevation.