Tensile load capacity of screw anchors in early age concrete

Screw anchors are gaining popularity in construction due to simplicity of their installation, ability to load them straight after the installation and ease of their removal. Existing models to predict the strength of screw anchors under tensile loading are based on the assumption that anchors are installed in mature concrete. This assumption is normally violated to escalate construction time. There is limited knowledge available in literature on behaviour of screw anchors in early age concrete. This research focuses on evaluating the behaviour of screw anchors installed and loaded in early age concrete. The relationship between the tensile and compressive strength of concrete as well as the ultimate strength of anchors and observed modes of failure are presented for a particular screw anchor based on 70 tensile tests. The experimental results have also been compared with the predicted values from the literature and specifications provided by the anchor manufacturer.