Perspex Models Test And Analysis On Anti-overturning Performance Of Curved Girder Bridges

With the continuous development of the transportation industry in our country and the accelerating process of urbanization,more and more curved beam bridges have been built to accommodate the changes in road alignment.In recent years,there have been many cases of overturning accidents of single-pier curved beam bridges across the country,causing major economic losses and extremely bad social repercussions.In this paper,the bridge of Guangdong-Chongqing expressway with overturning accidents in 2015 was taken as the reference bridges.The orthogonal scaled plexiglass model test and ANSYS numerical simulation were employed to investigated the overturning resistance performance of curved beam bridges.The main research contents and achievements are as follows:(1)Orthogonal test through three plexiglass models,the change law of the vertical displacement,strain and branch reaction force of the curved beam bridge as the vehicle load increases step by step until overturning is obtained.When the curved beam bridge is overturned,the strain at each measuring point is much smaller than the ultimate strain,that is,the overturning state of the curved beam bridge can be approximated as the rigid body rotation of the upper structure.(2)By establishing the finite element model of the test sample and comparing the numerical analysis with the experimental results,the rationality of the numerical simulation method of the curved beam bridge solid model is discussed to provide reference for the accuracy of simulation in the finite element software.(3)Based on the test results and finite element calculation results,through the analysis of range and variance,it was found that among the main influencing factors of the overturning of curved beam bridges,the impact of pre-eccentricity of middle pier on the anti-overturning performance of curved beam is the most significant,followed by the vehicle spacing,again.It is the spacing of the beam end bearings and finally the radius of curvature.(4)Based on the further study of the above results,the anti-overturn axis of curved beam bridge is developed,that is,the circular arc passing through the outer bearings.Based on the postulate an effective anti-overturning stability coefficient formula is deduced.In order to facilitate the application,a simplified anti-overturn stability coefficient formula is deduced,as well as its corresponding critical stability factor.(5)Based on the previous results,the effect of mass eccentrity of the superstructure,preeccentricity of mid-pier bearings and the spacing of end bearings on the anti-overturn stability of curved bridges are discussed,the results indicate that,thicken the inner web size,asymmetric railing configuration and preeccentrity of mid-pier bearings can significantly enhance the anti-overturn stability coefficient of curved bridges,while the way of lengthen the spacing of end bearings has less effect compared to the other three ways.