There are several different types of weld stud concrete anchors, but the most commonly used for bridges, buildings and other types of construction to attach steel and concrete are headed concrete weld studs.
The basic design of all these types of concrete anchors, which may also be called shear connectors, is an upset head with an unthreaded shank. There is no need for threads on this type of anchor as the bottom is welded to the steel girder and the head will form the anchor in the concrete.
Using the Headed Concrete Weld Stud
For building construction using steel beams and concrete slabs, the weld stud concrete anchors are positioned in a very specific pattern and distance apart on the beam. The pattern and spacing are based on several factors including building requirements and regulations as well as the specifics of the project.
In most applications, the weld stud concrete anchors will also use a ferrule. This is a ceramic ring applied before the welding process. It is designed to sit on the surface of the metal at the base of the headed concrete weld stud. This ceramic ring serves several purposes. It will concentrate the heat in the area where melting of the surface and the stud is required, it will create a neater final weld by holding the molten metal, and it will also reduce oxidation at the site. Additionally, it provides additional protection for the operator.
After the weld is completed, the ferrule is broken off of the anchor, leaving a compact, solid weld in place. In most cases, this welding is completed using the drawn arc stud welding process which is fast, effective and leaves no visible sign of the weld on the underside of the steel plate.