A Finite Element approach for determining the full load-displacement rela onship of axially-loaded shallow screw anchors, incorpora ng installa on effects Author list

Screw anchors have been recognised as an innova ve solu on to support offshore jacket structures and floa ng systems, due to their low noise installa on and poten al enhanced upli capacity. Results published in the literature have shown that for both fixed and floa ng applica ons, the tension capacity is cri cal for design but may be poorly predicted by current empirical design approaches. These methods also do not capture the load-displacement behaviour, which is cri cal for quan fying performance under working loads. In this paper, a Finite Element methodology has been developed to predict the full tensile load-displacement response of shallow screw anchors installed in sand for prac cal use, incorpora ng the effects of a pitch-matched installa on. The methodology is based on a two-step process. An ini al simula on, based on wished-in-place conditions, enables the iden fica on of the failure mechanism as well as the shear strain distribu on at failure. A second simula on refines the anchor capacity using soil-soil interface finite elements along the failure surface previously iden fied and also models installa on through successive loading/unloading of the screw anchor at different embedment depths. The methodology is validated against previously published centrifuge test results. A simplified numerical approach has been derived to approximate the results in a single step.