Student Paper Competition Winner: Investigation of Vibratory Hammer Installation for Deeply Embedded Ring Anchor System in Sand-Video

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Video Summary

Sung Chin presents a study of vibratory installation for deep-embedded ring anchors (DERAs), compact anchors designed to provide high capacity for floating offshore structures while reducing material, transport, and fabrication costs. The proposed system uses a reusable follower to drive the anchor deep into sand. Vibration generates cyclic shear strain and excess pore pressure, weakening the surrounding soil and enabling penetration.<br /><br />A finite-element-based model estimates pile stiffness, vibration response, and the eccentric moment and operating frequency needed to reach the strain threshold for penetration. Comparisons with two field cases showed that its predicted operating frequencies were close to those used in practice. Applied to a 15-MW turbine anchor, the model found that denser sand and lower frequencies require greater eccentric moments; commercial vibratory hammers can meet the estimated requirements. The same hammer could also extract the follower. Future work will examine clay and layered soils. During discussion, Chin noted that adapting the model to assess vibration effects on nearby urban structures would require modifications.

Keywords

deep-embedded ring anchors

vibratory installation

floating offshore structures

finite element model

vibratory hammer