Behaviour of shear connectors in cold-formed steel sheeting at ambient and elevated temperatures

Cold-formed profiled steel roof sheeting can be directly connected to the top chord of a steel truss through powder-actuated shot nails or self-tapping screws. The lap shear behaviours of both shot nailed and screwed connections are studied in this paper using both testing and FE analysis at ambient and elevated temperatures. The studies for screwed connections show that four components of loading capacity, including bearing force between thin sheet and screw shank, frictional force between washer and thin sheet, frictional force between thin sheet and thick plate, and the bearing force by the tilting of thin sheet are identified and quantified. The studies for shot nailed connections show strong interactions among washer, shot nail, thin sheet and supporting plate. The protuberance feature developed during the nail driving process, which causes material in thick plate flowing upward, has a significant positive contribution to the loading capacity of the connection.

► FE modelling for screwed and shot-nailed connection at ambient and elevated temperatures.
► Models studied behaviours of connections in installation process and under shear loads, respectively.
► Four load components are classified for transferring shear loads through connections.
► Effects of plate curling and contributions of frictional forces among the parts are analysed.
► Protuberance in shot-nailed connection made a significant contribution for transferring shear load through connections.