Numerical modelling of CFST column to I beam end plate joints

Abstract

AbstractThe use of concrete‐filled tubular structural elements around the world has been boosted in recent years. The most common geometries for these sections are circular (CHS), Square (SHS) and rectangular (RHS). They have been extensively used in multi‐story buildings due to their aesthetical features and structural advantages, due to their favorable resistance to weight ratio. One of the limitations for using these geometries is the inaccessibility to the interior of the section, thus arising difficulties and added costs in materializing the connections. This paper presents a numerical study dealing with tubular columns to I beam end plate joints using welded studs as the connecting elements and aiming to evaluate their structural performance. Following a series of full‐scale monotonic tests performed at the Civil Engineering Department of the University of Coimbra, Portugal, with the abovementioned geometry, several numerical models using 3D nonlinear elements have been developed to investigate the mechanical response of these joints.The main variables were the column and beam geometries, the thickness of the hollow sections, and the presence or absence of infilling concrete. The numerical results have been compared to the tests performed under positive and negative bending moments, to validate the finite element model. The numerical model was proven to lead to accurate predictions of the initial stiffness and joint resistance. The model validation was followed by a parametric study with the abovementioned variables to investigate the influence of the governing components and behavioral features. The column face loaded out of its plane proved to be the governing component, with its width‐to‐thickness ratio having a significant role in determining both elastic stiffness and resistance, together with the endplate dimensions and the number of bolt rows in tension.