Theoretical analysis of channel type anchors subjected to pure tensile or pure shear loads

The use of channel anchors in concrete building construction is relatively new. Although the pullout or shear capacity of single short anchor bolts or welded studs can be reasonably predicted using the concrete failure cone method, a similar pullout or shear capacity prediction relationship has not been developed for channel anchors with more them one relatively closely spaced embedded anchor. A tensile pullout capacity prediction method was developed and a relationship is proposed based on a modified concrete failure cone concept. This modified cone method recognizes the intersection of failure cones when anchors are closely spaced as is typically the case in channel anchors. Predicted pullout capacities of several channel anchors obtained from the proposed relationship were compared to test results from three independent testing agencies. The prediction percentage errors ranged from 17.4 under-prediction to 8.8 over-prediction for cases where the pullout load was centered on the channel. Over 92 percent of the predicted loads for channel anchors with centered loads have less than 10 percent prediction errors. The total average error for this group of channels is 6.6 percent. This paper contains tables of results and figures supporting the proposed method of evaluating the pullout capacity of channel anchors. A Shear capacity prediction method was also developed and a relationship proposed based on the modified concrete failure cone concept. This modified cone method recognizes the intersection of the failure cone with free edge(s). Predicted shear capacities of channel anchors obtained from the proposed relationship were compared to test results. The prediction percentage errors ranged from 18.8 under-prediction to 21.6 over-prediction, with a total average error of 8.96 percent. This paper contains tables of results and figures supporting the proposed method of evaluating the shear capacity of channel anchors.