Numerical Study of Deconstructable Flush End Plate Composite Joints to Concrete-filled Steel Tubular Columns

This paper describes a three-dimensional finite element modelling of an innovative flush end plate semi-rigid composite joint, to a concrete-filled steel tubular column, using high strength blind bolts. This innovative composite joint is formed by connecting a precast concrete slab to the top flange of a steel beam using post-installed friction-grip bolted shear connectors to facilitate the deconstructability of the entire system. A finite element model is developed using ABAQUS software to study the structural behaviour and failure modes of these prototype joints. Both geometrical and material non-linearities, as well as the non-linearity of the contacts and interfaces, are incorporated in the model. Four full-scale laboratory test specimens having deconstructable flush end plate composite semi-rigid joint to CFST columns using bind bolts are tested, with the results then used for validation of the finite element model. The proposed numerical models developed are used for conducting an extensive parametric study, in which the effects of the reinforcement ratio, thickness of the precast concrete slab, degree of shear connection, number of bolted shear connectors, size of the blind bolts in the connection zone and thickness of the flush end plate on the structural behaviour of the composite joint to concrete-filled columns are investigated. A design recommendation in the form of an empirical equation is then formulated. (C) 2016 Institution of Structural Engineers. Published by Elsevier Ltd. All rights reserved.