Analysis Of Shear Lag In Curved Box Girder Under Seismic Loads

Curved box girder bridges are widely used in engineering because of itscharacteristic. But the shear lag effect of the box section caused some damage to thesafety of the bridge. Meanwhile, the bending-torsion coupling effect caused by thecurvature will exacerbate the effects of shear lag effect in certain. Scholars have done alot of research on the shear lag effect of curved box girder and achieved some results.However, most of the research was based on the static loads; the shear lag effect underdynamic loads was rarely involved. But the actual structures are working in dynamicloads; the results based on static loads can not fully meet the requirments. In this paper,the finite element analysis program ANSYS was used to create the finite element modelof curved box girdes and the shear lag effect in seismic loads was analyzed. The mainresearch contents and results are:1. Finite element models were created based on beam elements, shell elements andthree-dimensional soild elements. Compared the dynamic analysis results of each model,the results show that the shell elements ensured the accuracy of the calculation and wasefficient at the same time.2. The time history analysis was used in the stress response of curved box girderunder seismic loads. And the shear lag coefficients were calculated by a simplifiedcalculation method, which was taking the average of the stress values, instead of usingthe elementary beam theory. Results show that the values of the shear lag coefficientsfluctuatearoud the reference value in seismic loads. The impact of loads values’ changeson the shear lag effect is secondary.3. The impact of curvature, web spacing, height and web thickness on the shear lageffect under seismic loads was studied, and achieved the regular pattern of impacts onshear lag effect. The impacts of curvature and web spacing on shear lag effect areobvious.The above findings provide important reference value for engineering applications.