Effect Of Interfacial Interaction On Shear Properties Of Bolted Steel-UHPC Composite Structures

In recent years,ultra-high performance concrete(UHPC)has been developed rapidly,especially steel-UHPC composite structure,which has excellent performance and has important advantages in improving structural stress and crossing capacity,so it has been widely used in bridge engineering.At present,the domestic and foreign scholars on the stud connection steel structure interface shear bearing capacity and UHPC conducted some research and found that the stud connection steel structure and UHPC interface shear bearing capacity is significantly higher than the stud connection of ordinary steel and composite structure,pin connected steel structure and UHPC interface shear bearing capacity is not only simple controlled by carrying the weaker the stud,It is also affected by the interaction between the interface of steel-UHPC composite structure,but there are few relevant studies,and the shear mechanism of the bolted steel-UHPC composite structure under the influence of interface is not clear yet.This paper carries out research on the above problems,and the main work is as follows:(1)The effect of interfacial interaction on shear performance of steel-UHPC composite structure with stud connection was studied experimentally.The push-out test of steel-UHPC composite push-out specimen was designed.The influence of interface action on the shear performance of steel-UHPC composite push-out specimen was studied by comparing and analyzing the failure mode,shear capacity and load-slip characteristics of the specimen,and the influence range of interface action effect of steel-UHPC composite was explored.The effect of interfacial interaction on shear properties of ordinary steel-composite extruded specimens was analyzed.(2)The shear failure mechanism of bolted steel-UHPC composite structure under the influence of interface was revealed.Aiming at the problem that the shear failure process of conventional push-out specimens was difficult to be observed directly,a bolted steel-UHPC visualized push-out specimen was designed and made for testing,and the equivalence of visualized specimens was verified.The deformation response and failure characteristics of the interface between steel plate,bolt and concrete during loading process were obtained,and the shear failure mechanism of the steel-UHPC composite structure with bolt connection under the influence of interface action was revealed.(3)Numerical simulation of shear behavior of steel-UHPC composite structure with stud connection under interface effect.Constructed on the basis of experimental study,the shear performance of steel-UHPC combination structure finite element model for numerical study reveals the interaction of pin connected steel structure and UHPC is influenced by shear performance,explores the concrete strength,interface distance and diameter of stud,interface friction coefficient of steel structure and UHPC interface effects.