Study On The Reason And Rectification Strategy Of Transverse Deflection Of Walking-Type Incremental Launching For Steel-Concrete Composite Beam

Incremental launching construction has advantages of concentrating precast structure site,optimal organisation of production operations and construction shortcut,which is widely used in bridges crossing railway line. With its superiority,walking-type incremental launching has higher suitability and safety coMPared with traditional dragging-type incremental launching. Walking-type incremental launching was first applied to Jiubao bridge in Hangzhou of China in 2010.There is less research on its key technology,which is far from practical engineering’s need.Relying on incremental launching project,this dissertation developed special research on the transverse deflection of walking-type incremental launching for steel-concrete composite beam,which was based on theoretical analysis binding data statistic analysis. The major contents of this thesis are listed as following:First of all, on the basis of a large number of domestic and foreign literatures, the overviews of walking-type incremental launching were undertaken, and the research shortcomings in this field were found. Then, a project to study the reason, the rule and rectification strategy of transverse deflection of walking-type incremental launching for steel-concrete composite beam was put forward.Secondly, a model was built by software ANSYS,which analyzed the effects of girder body’s transverse deflection on pier’s transverse deformation,pier’s local pressure and steel box girder’s local stability.Meanwhile,the lift-up jack’s walking distance difference of each pier was counted every stroke to analyze the reason of box girder’s transverse deflection in the process of incremental launching.Then, after completion of each incremental launching recycle, the left and right box girder’s deflections after girder falling were counted.According to the deflection monitoring result, the mathematical statistics of deflection increment could be analyzed. Statistical results show that the monocyclic transverse deflection increment basically meets normal distribution.Finally, a more efficient rectification strategy was put forward to decrease rectification time, which used linear optimum theory combined with measured statistics of girder deflection.Above-mentioned research results can provide references for engineering application and further study of transverse deflection of walking-type incremental launching.