Study On Load Distribution Characteristics And Transverse Stability Of I-shaped Composite Beams

The I-shaped steel-concrete composite beam bridge uses two materials,concrete and steel,to give full play to the compressive properties of concrete and the tensile strength of steel.However,the flexural moment of inertia of the composite beam with simplified beam structure is smaller than that of the traditional composite bridge,and the load distribution effect needs to be further clarified.Further research is needed;in order to simplify the structure,the longitudinal coupling system is eliminated,and the force changes under the wind load need to be further clarified.Based on the above problems,this article mainly conducted the following aspects of research:(1)The research status of the composite beams with simplified beam structure in recent years at home and abroad has been collected.It is found that only a partial theoretical analysis is involved,and the load distribution characteristics of the composite beams have hardly been studied.Aiming at the above problems,based on the finite element theory and the converted lattice stiffness guide formula,the load distribution characteristics of the composite beam with simplified beam structure are given.(2)In order to verify the accuracy of the research on the load distribution characteristics of composite beams,this paper first proposed an evaluation method combining deflection and converted lattice stiffness.The four-span continuous composite beams with spans of 20 meters,30 meters and 40 meters,the bridge width of 9 meters and 12.75 meters were taken as the research object.The comparative analysis of the results confirmed the evaluation method of load distribution characteristics of composite beams proposed in this paper.accuracy.(3)Through the updated Lagrangian method,Von Mises yield criterion and load increment method and other finite element theoretical methods,and with the aid of finite element software,the transverse beams of the combined beams of the simplified beam structure in the non-combination phase and the bridge completion phase are subjected to lateral forces The performance was studied,and the transverse buckling mode and failure form of the composite beam with simplified beam structure were studied.(4)In the study of the transverse stability of the composite bridge at the noncombination stage,the application method of concrete load was proposed.The finite element analysis of the four-span composite beam with a span of 20 meters,a span of30 meters and a span of 40 meters confirmed the results The correctness of the method.(5)The proposed evaluation method of load distribution characteristics of composite beams and the new method simulation theory of transverse bridge stability analysis model are applied to composite beam bridges in Qinghai Province.The integrity and feasibility of this research method are analyzed and verified from practical engineering.After researching in this paper,it is recommended that in the design of multipiece I-section composite beams,it is not necessary to consider changing the detailed size structure of the beam to reduce the deflection of the bridge span.Regardless of whether the composite beam is in the non-combination stage or after the completion of the bridge,the fulcrum and the side span are easily damaged.To avoid local instability affecting the overall stable bearing capacity,during the design process,measures should be taken to ensure that the composite beam loses the overall stable bearing capacity.No local instability occurs before force.