Shear and bending behaviour of fin plate connection to concrete filled rectangular steel tubular column — Development of a simplified calculation method

This paper presents the results of numerical and theoretical studies into the behaviour of simple welded fin plate to concrete filled tubular (CFT) columns loaded by bending and shear force. Such connections represent a simple single-sided joint solution to steel CFTs and are commonly used in practice. The current design guidance encapsulated in CIDECT Guide 9 does not cover the ultimate strength of such connections. Hence numerical models have been developed and used to perform extensive parametric studies from which a simple manual calculation method has been developed for evaluating the strength of the column component of rectangular CFTs under shear and bending load imparted through a fin plate connection. The ranges of parameters encompassed by the model include column cross-section size, column thickness and fin plate length. The simple manual calculation procedure is based on defining a rigid plate deformation pattern for the column face and then applying the virtual work principle. The column face deformation corresponding to the maximum load has been found to be strongly related to the column width to thickness ratio and a method for evaluating this relationship has been proposed based on extensive numerical results. The load–deflection curve consists of two segments: the first representing the elastic behaviour from classic plate theory, the second obtained by plotting the deflection at the maximum load against the maximum load, both of which are obtained through the simple manual calculation procedure. The simple manual calculation method is compared favorably with a large range of finite element simulations. The proposed method may be used in the component based method for joints involving a fin plate component in shear and bending.

Research highlights
► Studying load–deflection behaviour of fin plate connection to rectangular concrete filled tubular columns.
► Including effects of yield line mechanism and membrane action in steel tubular face.
► Derivation and validation of simple manual calculation method suitable for design implementation.