Exploration Of The Enhancement Method Of Shear Connection Section In Steel-concrete Composite Beams

This paper relies on the application of basic research projects of the Ministry of Communications "Basic theory study on the construction of super large span steel truss-concrete composite continuous rigid frame bridge"(No.2013319814040),Shear connectors of mechanism of force transfer and calculation method in assembled prestressed steel truss-concrete composite beam carried out in-depth system of experimental study and theoretical analysis.The method of enhancement of the shear connectors in steel-concrete composite beams is explored.The main research work as follows:(1)Describe assembled prestressed and cast-in-place steel-concrete composite beams of shear connection construction.S-PC and PCSS of shear connectors in assembled steel-concrete composite beam were proposed.Explored between different shear connectors in assembled prestressed steel-concrete composite beams can be used together with the reason.Summarised the diseases of steel-concrete composite beams caused by a lack of shear connection.(2)Under the static load,research ultimate flexural bearing capacity,stiffness and working mechanism of the experimental beam in the negative bending moment section and analyzed different types of shear connection section of the loading behavior.Under the static load,found that the rigidity of shear connection section of the deformation were greater than the flexible shear connection section.The first reason,PCSS shear connectors are arranged uniform and pass the performance of longitudinal shear than S-PC shear connectors which are arranged concentrated.The second reason,after pouring hole of concrete of S-PC shear connectors is difficult to ensure the compactness and stiffness.The last reason,PCSS is bigger than the vertical stiffness of S-PC.(3)The method that embedded welding enhanced composite beam shear connection were proposed.After reinforcement,research ultimate flexural bearing capacity,stiffness and working mechanism of the experimental beam in the negative bending moment section under the static load.After the first local reinforcement,Test beam midspan deflection value reduced and test beam linear remains unbalanced linear before reinforcement.After the second local reinforcement,Test beam deflection value has no obvious ascension in total and test beam deflection linear symmetrical balance.Instructions of composite beam reinforcement method is proposed to achieve the effect of the shear connection.(4)Explored the calculation method of shear connection enhancement.Consider the interface slip effect of the steel-concrete composite beams and the balance equation was built with the elasticity theory.The total potential energy functional is established and using the variational method to solve the total potential energy functional.Slip and the deflection differential equation is obtained.Joint deflection boundary conditions to solve the deflection equation.The experimental values and calculated values coincide well.