Pullout capacity development of cast in place anchors with embedded studs

In this study, an experimental investigation was conducted on normal strength concrete to examine the pullout capacity variation of cast in place anchors with the embedded circular surrounding studs around the anchored rebar under monotonic loading. Keeping constant the compressive strength of concrete, diameter and embedment length of anchored rebar, influence of number of embedded studs and distance between the circular surrounding studs and anchored rebar were chosen as the experimental parameters. Studs were embedded circularly around the anchored rebar with 10 and 20 cm diameter and number of studs was 4, 6 and 8 in each layer. For control purpose, anchored rebar without embedded studs were also tested. Unconfined tension test was performed according to the guideline of European technical approval of metal anchors for use in plain concrete. Test results revealed that embedded studs increased the pullout capacity of cast in place anchored rebar, increasing the number of studs increased the pullout capacity gradually; however, there was no meaningful difference in the pullout capacity of anchored rebar with the increase of stud layer.