Headed Studs in Concrete: State of the Art: Discussion

Headed studs are smooth or deformed bars, usually short compared to the lengths of concrete members, with forged or welded heads for anchorage at one or both ends; they are used instead of conventional reinforcing bars anchored by hooks and bends. This commentary article discusses a recent study that describes several practical applications where the use of headed studs is appropriate (Ghali and Youakin, 2005). The authors noted that the main advantages of headed studs are simpler installation, less congestion of reinforcement, improved confinement, and more effective anchorage. They also contend that the use of a headed bar, as opposed to a bar with a hook, is advantageous in applications where there is demand for the yield strength at a section of the bar close to its end. In this commentary article, Thompson et al offer responses on five areas of the original study: cover dimensions, strut-and-tie modeling, the relative head area of headed bars, double-headed studs used as shear reinforcement in concrete I-beams, and the variety of heads currently available on the market. A closure by the original article's authors addresses each of these concerns.