Experimental Study On Shear Lag Of Curved Box Girder Under Earthquake

Curved box girder bridge is an important bridge type in bridge engineering. But shear lag effect cannot be ignored in curved girder bridge. In recent years, specialists get a good result in-depth research of curved box girder bridges, yet those researches are mainly performed shear lag effect of curved girder bridge under static load and dynamic load is absent. But the study of shear lag effect under dynamic load, especially earthquake action is less. So the intense research for shear lag effect of curved box girder under earthquake action is necessary. For this reason, cantilever curved box girder is chosen as the research object in this paper. Establish the shear lag effect of curved box girder analysis model based on ANSYS finite element software and analyze the shear lag effect of the model under earthquake action. Meanwhile shaking table test was carried out, analyzing the shear lag effect of the test model under earthquake action and comparing the consequence of numerical analysis with shaking table experiment. The mainly studies are as follows:(1)This paper has illustrated the concept and calculation method of the shear lag coefficient, and discussed the applicability and limitations of method in structure seismic test in laboratory condition.(2)This paper has conduct the finite element method analysis the dynamic response of curved box girder under earthquake action of different earthquake acceleration time history and adopt simplified shear lag coefficient calculation method to acquire the data of every node. The analysis results demonstrate that the shear lag coefficient of each node is close to every moment and change in the vicinity of the reference value. At the same time, it is concluded that the shear lag effect of cantilever curved box girder at fixed end section is more distinct than at L/2 section under earthquake action.(3)Conduct the analytical calculation of shear lag effect on cantilever curved box girder of material nonlinearity by ANSYS to study the influence of shear lag effect by changing geometrical parameters: radius of curvature, space of weds, flange width and so on under earthquake action. Summarizing the influence law of geometric parameters on the shear lag effect, it can be found that radius of curvature and space of weds influence the shear lag effect remarkable. Choosing these geometrical parameters reasonable can decrease the shear lag effect in the design of curved box girder bridges.(4)By Shaking table test studying and numerical analysis on cantilever organic glass curved box girder model indicate under earthquake action shear lag effect on the junction of web and flange of organic glass curved box girder model is obvious and shear lag coefficient of the same organic glass curved box girder under the condition of different earthquake action changes little. The result of experiment is close to ANSYS analysis, which proved the correctness and applicability of ANSYS numerical analysis.