| The traditional steel-concrete composite beam was improved,so concrete-partial-filled narrow-width steel box composite-continuous beams was created.On the one hand,concrete-partial-filled narrow-width steel box composite-continuous beams inherits a lot of advantages from The traditional steel-concrete composite structure beam such as high tensile strength,benefit overall performance,light structure weight and better seismic performance.On the other hand,concrete-partial-filled narrow-width steel box composite-continuous beams improves shortcomings of traditional beam,for example stability and crack.The steel-concrete composite beam is a composite structure in which a reinforced concrete wing plate and a steel beam member are combined through a shear connection to bear loads.The combination of the two materials enables the strength of both to be fully utilized,exerting the compressive strength of the concrete material and the tensile strength of the steel.Compared with ordinary concrete beams,it has smaller cross-sectional size,higher cross-sectional strength and greater span applicability.However,in the negative bending moment region at the middle bearing of the combined continuous beam,the concrete wing is easily cracked and the steel beam is easily buckling under pressure.There for the material properties of them can not be fully utilized.Concrete-partial-filled steel box composite beam is a new type of composite structure beam,which is filled with concrete in the negative bending moment region of the steel box to avoid the inward buckling,which effectively improves the strength and stiffness of the composite beam and the stability of the beam.For study the shear failure mode and vertical shear mechanism of concrete-partial-filled steel box composite beams and the influence of different parameters on vertical shear performance,some reasonable suggestions for shearing design of concrete-partial-filled narrow steel box composite continuous beams are proposed.To provide designers with a simplified calculation formula for the shear resistance design of a concrete-partial-filled narrow steel box composite continuous beam.In this study,six test beams with different reinforcement ratios,steel web thicknesses,and different amounts of filled concrete were used to complete The symmetrical static loading test.The study includes:1.In static force loading test,it analyzed the crack law of composite beam sufferingnegative moment,buckling process and form changes of partial steel box and stress and strain of slip deformation.Find out how the reinforcement ratio,the thickness of the steel box,the filling area of the concrete composite beam influence the crack development,ultimate bearing capacity and deformation.2.The deflection,stiffness and shear strain of the composite continuous beam specimen were calculated by the stiffness reduction method.The shear capacity of the concrete wing,steel box girder and the concrete in the filling area were calculated based on elastoplasticity theory.Finally,it obtained the shear capacity of the whole composite beam.A comparison of calculation results and test data indicated that the test results were in a good agreement with theoretical calculation.3.It modeled concrete-partial-filled steel box composite beam and analyzed the deflection and strain of composite beams under negative moment in ANSYS software.,Comparing numerical Simulation results from ANSYS and test results,it indicated that test model was relatively accurate and reliable.Through the test we can know about : under the impact of hogging moment,concrete in the filling area of the concrete-partial-filled steel box composite continuous beams carries part of the shear of the section,longitudinal reinforcement in the flange restrains the crack developing of concrete flange,and transverse reinforcement plays a role in restricting shear connectors;the above factors jointly improve the local stability and shear strength of the composite beam. |
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