Tensile capacity of screw anchors due to the pull-out failure mode

Document Type

Conference Proceeding

Publication Title

FIB 2018 - Proceedings for the 2018 fib Congress: Better, Smarter, Stronger


Federation Internationale du Beton (fib)


School of Engineering




Mohyeddin, A., Gad, E., & Lee, J. (2018). Tensile Capacity of Screw Anchors Due to the Pull-out Failure Mode. In The International Federation for Structural Concrete, 5th International fib Congress, Melbourne.


The Concrete Capacity Design (CCD) method is the only existing method available in the literature to predict the strength of screw anchors under the tensile loading. In CCD method, the assumption is that the anchor fails due to the concrete cone failure mode. However, previous studies have demonstrated that screw anchors usually fail as the result of a combined pull-out and cone failure, or pull-out failure mode rather than a pure cone failure mode. This means that in many cases the experimental results do not support the main assumption behind the CCD method. In an experimental program, whereby a total of 180 tests were conducted on a particular type of screw anchor, 72 anchors failed due to pull-out failure mode. The results related to this specific failure mode are used to propose an equation to predict the tensile capacity of screw anchors failing under the pull-out failure mode. The experimental results are further compared with the predicted values by the CCD method and specifications provided by the anchor manufacturer. © 2019 by the fib. All rights reserved.

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