Behaviour of sleeved bolt connections in precast concrete building frames

This thesis describes an experimental investigation and an associated finite element study of the behaviour of sleeved bolt beam-to-column connections. Despite the popularity of such connections in precast concrete building frames, little experimental data has been available regarding their behaviour under static vertical loading. For this reason, two series of tests were performed on full scale joints. The main focus of the first series was to examine the effect of bolts density per joint on its strength, stiffness and failure mode. In the second series, the influence of concrete confinement upon the joint ultimate strength was studied. Failure of joints was mostly governed by shear yielding of the bolts. However, concrete failure was reported when much weaker concrete with minimum confinement was employed. Deformation data obtained from all tests was used to interpret the joint behaviour. Test results have also shown that increasing the number of bolts per joint not only increases its ultimate strength but improves its load-deflection and moment-rotation characteristics as well. The parameters affecting the behaviour of such connections have been used to develop three-dimensional finite element models of both the single and double-bolted joints. This was achieved by using the software package (ANSYS). Material properties, geometrical dimensions, boundary conditions and loading were carefully given as input data to represent, as realistically as possible, those of the tested joints. Material nonlinearity was considered for both steel and concrete. The opening and closing of initial geometric gap at the interface between the bolt and the sleeve were also accounted for. The developed models were then used to determine the stress and deformation distributions within the joint components. The models reached their ultimate loads successfully. They predicted, with a very good accuracy, the joints response under loading.