Shear Lag Effect And Ultimate Bearing Capacity Of The Double-Girder Steel-Concrete Composite Beam Considering Slip Effect

Shear lag effect of the double-girder steel-concrete composite beam bridges is obvious due to the large distance between the main girders.This thesis takes a doublegirder steel-concrete composite beam as the research object to explore the influence of the interface slip on the shear lag effect and the ultimate bearing capacity of the composite beam.The main research contents and achievements are as follows:1.Based on the energy variation principle,the analytical stress solution of the double-girder steel-concrete composite beam under various load conditions without considering the interface slip is derived.The finite element model of the double-girder steel-concrete composite beam without the effect of interfacial slip is also established,and the derived formulas are verified by the finite element numerical simulations.2.Based on the energy variation principle,the analytical stress solution of the double-girder steel-concrete composite beam subjected to various load cases considering the interface slip is further derived.The finite element model of the double-girder steelconcrete composite beam considering the interface slip effect is also established,and the derived formulas are verified by the finite element numerical simulation results.3.The finite element model of a double-girder steel-concrete composite beam considering the material nonlinearity is established.The ultimate bearing capacity of the beam is investigated by using the finite element method,and the influence of the interface slip effect on the ultimate bearing capacity of the double-girder steel-concrete composite beam is further studied.4.Shear lag effect and ultimate bearing capacity of the double-girder steel-concrete composite beam are studied through the experimental test of a composite beam.The experimental results are compared with the results of the finite element method and analytical solution.The results demonstrate that the shear lag effect of the concrete deck by the stress formula derived in this thesis is accurate.The results based on the derived analytical solution considering the slip effects are well matched with the experimental results.The ultimate bearing capacity of the beam calculated from the finite element model considering the material nonlinearity and the interface slip effect is also consistence with the experimental test results.