Distortion Behavior And Experimental Study Of Composite Curved Box Girder With Corrugated Steel Webs

The torsional stiffness of corrugated steel webs box girders is reduced by replacing the traditional concrete webs with corrugated steel plates.Especially for curved box girders,under load,due to the relationship between curvature radius,the section will generate additional torsion,which has the coupling effect of bending and torsion,and its distortion effect is more significant.In the current distortion theory of corrugated steel webs box girders,most of them analyze the distorted normal stress,but little research has been done on the distorted shear stress.In view of this,the distortion properties of corrugated steel webs are studied by theory,experiment and finite element method.The main research contents and results are as follows:(1)This paper clarifies the corresponding relationship between distortion theory and constrained torsion theory.According to the characteristic that corrugated steel webs do not produce longitudinal stress,the distortion differential equation of curved beams with corrugated steel webs is established based on box girder theory,and the calculation formula of distortion shear stress is deduced under the condition of element stress balance and distortion shear stress not forming torque along the section.The distortion differential equation is solved by Fourier series solution method.In addition,according to the similarity between the generalized bending theory and the distortion theory of box girder,the distortion differential equation considering shear deformation is established.By comparing the normal stress and shear stress of the section with the finite element method,the results are basically consistent.The calculation of the normal stress and shear stress of the curved box girder with corrugated steel webs is reasonable and can basically reflect the variation law of the section stress.(2)In order to study the distortion performance of curved box girder with corrugated steel webs,the torsion test of curved box girder with corrugated steel webs was designed.Vertical displacement,radial displacement and web strain are measured.The experimental results are compared with the finite element and theoretical results.The results show that the web shear stress distributes uniformly along the height,and the measured values agree well with the finite element values and theoretical values.The measured results of Web shear strain of test beams are consistent with the results of finite element and theoretical values along the longitudinal distribution law,which shows that the theoretical calculation accuracy of this paper is high.(3)The effect of shear deformation on distortion stress is studied.The results show that the distortion effect decreases when shear deformation is considered(the distortion stress considering shear deformation is about 10% smaller than that without shear deformation);the larger the radius of curvature,the smaller the effect of shear deformation on distortion stress;the larger the web thickness,the stronger the distortion resistance of the web thickness.The effect of shear deformation on distortion effect decreases with the degree of Web shear deformation.The distortion effect of curved beams with corrugated steel webs is calculated and analyzed by using the theory and finite element method in this paper.The results show that the ratio of Web distorted shear stress to bending shear stress is up to 50% in this example,and the distorted shear stress can not be neglected.Under load,the shear stress of inside and outside web of curved beam is generally unequal,and the shear stress of inside and outside web is less uneven when load acts on outside of curved beam.The smaller the radius of curvature is,the greater the non-uniformity of shear stress in the inner and outer web.When the curvature radius of curved girder bridge with corrugated steel webs is large,that is,the center angle is small enough,in order to calculate conveniently,the web shear stress can be analyzed according to the straight bridge.