Experimental Study On Bending Performance Of The Pattern Steel-encased Concrete Composite Beam

Research and engineering practice show that the work performance of common steel-encased composite beam mainly depends on the degree of connection between steel and concrete. But the natural bond between steel and concrete is often small, which cannot provide sufficient combination effect, then a large number of shear connectors are setted up in the component, which leads to big welding workload,and inconvenience construction.Pattern steel encased concrete composite beams with profiled steel sheet are putted forward. The steel of C-beam is used by pattern steel sheet,then the press steel sheet is fixed on the C-steel beam flange by the bolt, finally the concrete is poured into the C-steel beam rib and the steel plate surface.The convex lentils type pattern in the plate surface can largely enhance the bond between the steel and concrete, wich can reduce the number of shear connectors. The composite beam structure is simple, of strong combination, and of convenient construction,which lead to industrialization production and obvious economic benefit,which can be widely used in civil building floor structure.Considering the strength of concrete, the size of the composite beams section, bolt diameter, spacing, longitudinal reinforcement, shear span ratio and other factors,7simply-supported beams are designed and tested by static load.Then the experiment phenomena, failure pattern, ductility performance, characteristics of the load, load-deflection curve, the load-strain curve,slip-strain along the height distribution curve and load-curve are analysed and researched deeply.The following are obtained by the theoretical analysis:the slip resistance formula of the beam, judgment of composite beam failure pattern, the slip effect of the elastic capacity formula,the ultimate bending bearing capacity formula of the full slip resistance and partial resistance of the beams.The model of pattern steel encased concrete composite beam is established on the basis of the good choice of the materials,constitutive relation and failure criteria, then the flexural strength is simulated.Finally test values, the theoretical calculation value, and the simulation value are compared with each other, which are in good agreement.