Experimental Research And Finite Element Analysis On The Bending Performance Of Steel Box-concrete Composite Slabs

The assembling unit of assembled steel box concrete composite caisson is steel box concrete composite slab.This kind of component has the characteristics of small height width ratio and thin steel box wall.At present,there is a lack of research on bending performance of this component,and blind design will produce a huge potential safety hazard.Therefore,this paper carries out the experimental research and finite element analysis of the bending performance of the steel box concrete composite slab,which provides the basis for the engineering application and theoretical research.The following is the main work of this paper:(1)Seven bending members of composite plates are tested.The main parameters of the specimens are the wall thickness of steel box and the arrangement of shear connectors.The ultimate bending moment of the specimens is compared with the calculated value according to the specifications.The results show that the failure characteristics of the specimens are the tensile yield of the bottom plate,the local buckling of the top plate and the compression concrete collapse.Most of the specimens yield The ratio of load to ultimate bearing capacity is less than 0.7,and it can bear the load even when the deformation is large,so it has good ductility;the longitudinal strain of steel is linearly distributed along the height direction,and the section strain conforms to the assumption of plane section;the stud will cause the splitting of concrete in the tension area and reduce the bearing capacity of composite plate;the stiffener will effectively delay the local buckling of roof and improve the bearing capacity of composite plate;The ultimate bending moment of each specimen is in good agreement with the calculated value according to the simplified algorithm of Han Linhai,and the design based on the simplified algorithm of Han Linhai is safe.(2)The finite element software ABAQUS is used to analyze the composite plate,and the results of the finite element analysis are compared with the test results.The results of the two are in good agreement with the test results in the aspects of failure characteristics,bending moment deflection curve and bearing capacity.Based on the verified non-linear finite element model,43 finite element analysis specimens were designed,and the parametric analysis of bending capacity was carried out to study the influence of steel strength,concrete strength,steel plate thickness and section height width ratio on bending performance of composite plates.The results show that: the steel strength has little effect on the rigidity of the test piece,and has a significant effect on the bearing capacity;the concrete strength has no significant effect on the bearing capacity of the composite plate;the bearing capacity and rigidity of the test piece increase with the increase of the steel plate thickness,among which the influence of the bottom plate is the most obvious,followed by the web plate,and the influence of the top plate is the least,and when the thickness of the top plate exceeds 8mm,the increase of the thickness of the top plate has a significant effect on the test piece The influence of bending performance is very small;the increase of the ratio of section height to width significantly improves the bearing capacity of the composite plate;the stud will aggravate the cracking of concrete in the tension area and produce stress concentration,which is the adverse factor affecting the bending performance of the composite plate.