In many types of composite construction, typically with concrete slabs or decks and steel beams or structural components, headed anchor studs are used to fasten these two very different materials together.
The use of these weld studs, which are also sometimes called shear connector studs, allows for the steel and concrete to be tied together, allowing for a complete connection between the two materials. This is important as both, if not connected, would move and respond to force differently, resulting in a floor or a bridge deck that sagged towards the middle from all sides.
With headed anchor studs that are welded to the steel structure and then the addition of the concrete, the two are held solidly as one piece of composite construction. This not only prevents the separate movement and eventual twisting and sagging but also creates a stronger composite section than either material would be independently.
The Design
The shape of the shear connector is somewhat similar to a traditional bolt. The head, however, is rounded and completely flat. The base of the headed concrete stud has a small protrusion or ignition tip and a slightly chamfered edge. This does impact the overall length after welding by reducing the unwelded length by approximately 1/8th of an inch for those that are ½ inch in diameter or less and by about 3/16th for diameters of 5/8th of an inch and greater.
Unlike bolts, the headed anchor studs are not threaded. They are not used to fasten the two materials in the traditional sense; rather they are positioned in patterns determined by the design requirements and size of the anchors.
Each of the shear connectors will be sold with a ferrule. This is essential to hold the molten material in place to secure a complete weld as well as to prevent the need for any other materials, such as additional flux, to complete the drawn arc welding process.