Experimental Study On Shear Lag Effect Of Curved Box Girder Under Vehicle Loads

At present, curved box girder bridges already have been widely applied in project practice. In the box girder, the research on shear lag effect is an important part in this field. It is well known, due to the negligence of shear lag effect in the box girder, it has brought the great catastrophe and property damage to the human society. At the same time, the crankle coupling effect of curved box causes its shear lag effect distribution rule to be more complex, the problem more deeply. In the existing literature, the static load on shear lag effect of curved box girder have been widely studied, but the dynamic load research have been rarely reported. Therefore, this article devotes to the research that under dynamic the load function shear lag effect of curved box girder. It selected the vehicle load as the object of study, using the large general-purpose finite element software ANSYS to modeling for the numerical analysis and then built plexiglass model to carry on the experimental analysis. The above findings have the important significance of theor-etical study and reference value for the engineering applications.The main content of this article are concluded as follows:(1) Introduced the study significance and the main study method of shear lag effect on the curved box girder under dynamic load, mainly introducing the research about shear lag under the dynamic loads in recent years.It expounds the theory of dynamics,such as transient dynamics, simplying vehicle load and selecting unit in the finite element method.(2) Large general-purpose finite element software ANSYS is adopted to study the influence of parameter to shear lag effect of curved box girder under the vehicle load, including vehicle load size, speed and function position. It also has discussed the comparison of vehicle load constant concentrated force and harmonics force, the comparison of simple support restraint and clamped restraint. Then established and studied a curved box girder model with the cantilever restraint, concluding dynamic shear lag effect distribution in the curved box girder under the condition.The results show that the changes of vehicle load speed,function position and support restraint affect the shear lag effect of structure obviously.(3) Vehicle load model test and numerical analysis are used to study the cantilever plexiglass curved box girder, concluding the distribution of shear lag effect of cantilever plexiglass curved box girder under the vehicle load. The result show that there are more positive shear lag effect at the junction of roof and web of the structure, and there are different distribution of shear lag effect on the cross-sections obviously.Finite element analysis values match with experimental results approximately, verifying the finite element reliability.