Numerical investigation of the response of expansion anchors used to attach helical pile connectors to concrete foundations

This paper evaluates the performance of expansion anchors used to attach helical pile connectors to foundations. The anchors’ response to pullout loads was evaluated using nonlinear finite element analysis with the aid of the commercial software, Abaqus. The connector capacity under horizontal movement of the foundation for different anchor diameters, embedment depths, and anchors’ spacing is reported. It was found that the pre-tension load had no influence on the anchor ultimate capacity, but affected the anchor response at service load levels and the displacement at failure. Under pullout loading, increasing the anchor diameter resulted in a more brittle response, but did not affect the ultimate capacity when the concrete tensile strength dominated the response. No interaction between anchors was observed for spacing ≥ 1.67 times the anchor’s embedment depth. A modification to the helical pile connector configuration is proposed.