Effects of Binding Bars on the Integrity of End Plate Connections to Concrete-Filled Steel Tubular Columns

Abstract

Abstract Concrete filled steel tubular (CFST) columns have been used widely because of the confinement provided by the steel tube to the concrete core and the concrete restraint against local buckling of the steel tube. In engineering practice, end plate connections are often used to connect steel beams and CFST columns, and conventional connection design methods for steel structures are often used. This paper deals with the effects of binding bars in potentially enhancing the integrity of end plate connections to CFST columns. Binding bars and blind bolts are considered to connect the steel beam to the CFST column in composite beam-column connections; with the aim to avoid the separation of the steel tube from the concrete core under tensile loading. A finite element (FE) model has been developed to simulate the end plate connections using binding bars and blind bolts. The various effects of the tube thickness, endplate thickness and binding bars on the connection behaviour have been investigated using the developed FE model. The results show that the binding bars are a promising approach into the development of end plate connections which enhance the initial stiffness and their ultimate load capacity. The tensile load from the steel beam can be transferred into the steel tube and concrete core of the CFST column through the combined action of the blind bolts and binding bars. Thus, the integrity of the steel beam to CFST column connections can be enhanced by applying the binding bars in bolted end plate connections.