Torsional Behavior Of Orthotropic Steel-Concrete Composite Bridge Deck With U-Rib

By adding thick concrete layer,the steel-concrete composite deck is formed,which has better fatigue resistance and greater longitudinal stiffness than the traditional orthotropic deck,and solves the problem of pavement vulnerability and fatigue crack in detail.Most of the previous studies focused on its fatigue performance,but little was known about its torsion behavior,and torsion behavior under eccentric load is a problem that can not be ignored.it’s necessary to consider the torsional effect caused by partial load to ensure that it is more safe and reliable in the construction process.The main work of this article is as follows:1.Based on assumptions of the derived Euler Bernoulli beam、rigidity at circumference、plane cross-section and deformation compatibility of surrounding the bolts,take composite beams’ rigid twist Angle θ and deflection y as basic parameters,a composite structure bending torsional linear differential equations of mutual coupling was established,based on the finite difference method,the bending differential equation was solved,using operator solution to solve differential equation of torsion and obtain analytic expression.Spatial finite element method and classical beam theory are used to check the deflection and internal force of cantilever beam structure system,the results show that the proposed theory is accurate and the analytical formula of torsion Angle needs further verification.2.The full-scale torsion test was carried out on the basis of Ruyi island cross-sea bridge approach project.In view of the influence of key parameters on the stress and displacement of the u-rib of the orthotropic steel-concrete composite bridge deck structure,the finite element parameter analysis shows that the thickness of concrete layer and the thickness of U rib are the key parameters affecting the main tensile stress and vertical displacement of U rib.The experimental results are compared and analyzed with the theoretical calculation program and the analytical formula of torsion angle.3.In view of the sliding effect of the torsional action of the orthotropic steel-concrete composite bridge deck,the sensitivity analysis of the key parameters was carried out by using the finite element model considering slip,and the key parameters affecting the maximum slip and maximum deflection were obtained respectively.The increase coefficient of deflection considering slip was further explored,and the value of the increase coefficient of deflection corresponding to each key parameter was obtained within the range of 1.10~1.21.The results obtained in this paper can provide a basis for the design and calculation of orthotropic steel-concrete composite bridge deck...