| The U-shaped steel-concrete composite beam has the advantages of high bearing capacity and good ductility,and its assembling construction technology also conforms to the current trend of building structure to the assembly-type development.In this paper,ten Web-embedded inverted T-shaped Steel-concrete Composite Beams(WTSCB)and nine Web-embedded U-shaped Steel-concrete Composite Beams(WUSCB)were designed with embedded connectors.The experiments and theoretical analysis of these two composite beams were carried out to study their shear capacity.The main research work and results are as follows:(1)The shear experiment of WTSCB was carried out,and five different patterns of connectors were designed,including swallow tail,gear,modified gear,circular hole and steel bar.The influence of connector patterns and the concrete slab width were considered.The failure modes of each specimen were analyzed and summarized.The mechanical properties such as stiffness and shear capacity were analyzed based on the sheardeflection curves.The shear transfer mechanism of inverted t-shaped steel webs was studied based on the equivalent stress distribution in shear span.Compare and evaluate the effect of different shear connector and find the reasonable form of shear connector.The effective patterns of shear connector were found by comparing the effect of different shear connectors.(2)Based on the test results of WTSCB,the shear experiment of WUSCB with swallow tail embedded connector was carried out.The influence of parameters such as connector spacing and inclination angle,longitudinal bottom rebar diameter,bottom studs and stirrups,steel web thickness,concrete slab width,and shear span ratio were considered.The failure modes of each specimen were analyzed and summarized.The mechanical properties such as ductility and shear capacity were analyzed based on the shear-deflection curves.The shear transfer mechanism of inverted t-shaped steel webs was studied based on the equivalent stress distribution in shear span.(3)By using ABAQUS finite element analysis software,the finite element models of WUSCB specimens were established and verified.The stress distributions of concrete flange,concrete web,U-shaped steel and reinforcing bar were analyzed by finite element models,and the mechanical mechanism was studied.Based on the finite element models,the four parameters including concrete slab width,shear span ratio,web height-thickness ratio and bottom rebar ratio were analyzed,which provided numerical basis for the design method of shear capacity of WUSCB.(4)Based on the test results and finite element parameter analysis,the concept of effective shear width of the concrete overhanging flange was proposed,and the formula of effective shear width coefficient of the overhanging flange was obtained by fitting the calculation results of the finite element models.The shear capacity design method of WUSCB was proposed.This design method considered the contribution of concrete,Ushaped steel webs and dowel action from bottom longitudinal bars,which could accurately predict the shear capacity of composite beams. |
