Joint slip in steel electric transmission towers

Joint slip is the relative displacement of a bolted joint under shear. It is greater in transmission towers as bolt diameters are small, members joined are thin, bearing type joints with a lower clamping force are used, and coefficient of friction of galvanized faying surfaces is low. This study on behaviour of such joints, incorporated 36 joint tests, generated joint slip data and developed mathematical expressions to describe slip and load-deformation behaviour. As currently used construction clearance was found satisfactory, joint slip cannot be eliminated. Hence, incorporation of the reported joint slip data or mathematical expressions in tower analysis software will refine their results.