Research On The Behavior Of Steel-Concrete Curve Composite Beams Under Combined Bending Moment And Torque

With the advantages of light weight,large span,short construction period,good seismic performance,structural stability,the curved bridges which have a horizontal curve has gradually become the mainstream structure of bridge construction and design,but in the use of the stage it often worked in the complex state of bending and torsion coupling.At present,there are few researches on the mechanical behaviors of the composite beams under curved and torsional coupling.This paper is based on the natural science foundation of Hebei Province Research on the Mechanism of Flexural-torsional Effect of Prestressed Concrete Composite Beams with Corrugated Steel Webs(E2018210149).The bending and torsion effect and the distorsion effect of the steel-concrete curve composite beams are studied.The major jobs and conclusions are as follows:(1)Using M/R method converts curved composite beams into equivalent linear composite beams,the constrained torsion control differential equation which takes into account the difference of full cross-section materials is deduced by using the A.?.? ??????? constraint torsion theory.The analytic solution of torsion Angle and double moment under different types of loads is given by the initial parameter method;(2)Based on the distortion control differential equations and Considering the differences in the material of composite beam sections,Using the M/R method and the elastic foundation beam comparison method,a finite element model for the distortion of curved composite beams was established,Distortion angle and distortion double moments were analyzed;(3)The rigid torsion and distortion effect under different loading conditions are calculated by using the initial parameters and the comparative finite element method.The distortion Angle and the distortion double moment are distributed in parabola line along the beam axis,the torsional effect of cross section cross section is the most,the distortion effect is the least in the drive condition,the distortion effect producedby concentrated load is the largest.Under the action of dead load or lane load,the rigid torsion effect is parabolically distributed.Rigid torsion effect is distributed in a triangular pattern under vehicle loads.In the stage of constant load conditions,Rigid torsion effect is maximum.Rigid torsion effect is minimal under the action of centrifugal force on the driveway.Under the action of total load,the torsional stress ratio is triangular distribution along the section;(4)The distortion effect was analyzed by Midas /civil in four aspects: span ratio,transverse baffle number.As the radius of the curve increases,the distortion stress ratio decreases.With the increase of span,the distortion Angle,distortion double moment and distortion positive stress are increased.As the number of transverse partitions increases,the distortion stress ratio decreases.The cross section height(high span ratio)has little effect on the distortion effect of the curved composite beam;(5)The distortion stress ratio is analyzed by regression analysis and numerical fitting method,the formulas for calculating the spacing of transverse baffles are obtained for the use of arbitrary span closed section curves.Through the finite element data and the formula,the data is calculated by comparing and analyzing the formula with certain accuracy,it can be used as the auxiliary test formula for the spacing design of diaphragm.