Behavior of Anchors in Cracked Concrete under Tension Cycling at Near-Ultimate Loads

This study investigates anchor failure mechanisms associated with tension cycling at near-ultimate load levels. Experimental tests with post-installed anchors in cracked concrete were performed. Three types of commercially-available post-installed anchors and one modified anchor were selected to produce distinctly different failure modes. The cracks in the concrete had widths representative of earthquake conditions. The anchors were subjected to monotonic and cyclic tension loads. The results demonstrate that anchors exhibiting failure modes other than anchor steel failure can perform reliably during tension load cycling at near-ultimate levels. The results also indicate that the current definition of ductility in anchor design guidelines must be improved since the current ACI code requirements do not achieve the intended goal of large anchor deformations. These requirements should be coupled with a specified strain length in tension for the anchor in its installed condition.