Behaviour of semi-rigid composite connections subject to wind loads

This thesis describes a numerical study and an experimental investigation of the behaviour of semi-rigid beam-to-column composite connections subject to wind loads. Connections in composite frames are normally designed as pin-jointed connections. Diagonal wind bracing is included in such buildings to resist wind loads. The use of semi-rigid connections in the design of such frames can provide substantial savings in material and erection costs. It also avoids the intrusion of bracing into the useful space within the building.The connection was studied numerically using a finite element package (ANSYS). The parameters affecting the behaviour of the connection have been used to develop two-dimensional finite element models for the different configurations. A three-dimensional model was also developed to check the accuracy of the two-dimensional analysis. Material properties, geometrical dimensions, boundary conditions and loading were carefully given as input data to represent, as realistically as possible, those of the actual joint. Material non-linearly was considered for concrete, steel, reinforcing bars and shear connectors. The bolt slip and the construction tolerance were also accounted for. The developed model was then used to determine not only the overall stiffness of the frame but also the stress and deformation distributions within the joint components. Different options for stiffening up the joint laterally were also studied. The models predicted with a very good accuracy the joint lateral stiffness under horizontal loading. Also they provided useful information which could not be obtained experimentally e.g., concrete stresses, tensile stresses in the reinforcing bars.An experimental investigation was carried out to verify the safe behavioural prediction of this type of connection. Because of the high cost and time consumption required to make the sample, a single and representative connection was selected on which the experimental work was carried out.