Research On Shear Lag Effect Of Through Spine Girder For Urban Rail Transit

The main suitable beam type of urban rail transit viaduct is T beam,Box beam,Groove beam and Through spine girder. Currently, T beam and Box girder have been used mostly in urban rail transit viaduct at home and abroad. But the application of Groove beam and Through spine girder is less, especially there is no application example in domestic about through spine girder, which was internationally used in Calculi light rail in Canada. Through spine girder bridge is a new type of urban rail transit viaduct, which has unique advantages of low bridge building height and unaffected by span change.At present, the research on through spine girder is few at home and abroad, only mentioned in overview and outlook of references. For through spine girder is the structure of small box adding big cantilever, cantilever flange plate is long, as a part of beam, participating in the main beam buckling, the transverse shear lag effect is very significant; Meanwhile, when the load transversally passed to the spine girder through cantilever plate produces transverse bending, there exists the problem of longitudinal shear lag effect.In reference to the research methods of shear lag effect of the box design theory, the shear lag effect of through spine girder was studied in this dissertation. The three dimensional space model of through spine girder was established and analyzed by the universal finite element software-ANSYS. The main contents are presented as follows: (1) Compared with the analysis results of SOLID 185 solid element model and SHELL93 shell element model, the reasonable finite element was determined to choose for building model. (2) Transversal shear lag effect of through spine girder under the case of longitudinal bending was studied, and the influence of transversal shear lag effect under this circumstance of different kinds of load and different load-bearing position was analyzed. Based on shear lag coefficient obtained, transversal effective distribution width of through spine girder was further analyzed, and initial fitting formula of transversal effective distribution width was given. (3) Longitudinal shear lag effect of through spine girder under the case of transversal bending was studied, and the influence of longitudinal shear lag effect under this circumstance of different kinds of load and different load-bearing position was analyzed. Based on shear lag coefficient obtained, longitudinal effective distribution width of cantilever flange plate of through spine girder was further analyzed, and fitting formula of longitudinal effective distribution width was given. Via the analysis of transversal and longitudinal shear lag effect, suggesting formula of effective distribution width was put forward, which presents a reference for the design of through spine girder for urban rail transit viaduct.