ABSTRACT
Many offshore facilities are founded on, or are anchored with, piles to which the structure transfers large horizontal loads relative to the imposed vertical load when compared to onshore installations. Examples include offshore wind farms or floating offshore facilities (such as FPSOs). Due to the often low soil strength near the mudline large pile dimensions are required in order to mobilise the required lateral resistance. The recently developed concept of expanded cross-sections or ‘wings’ near the pile head (Deutsches Gebrauchsmuster 2005) has been shown to increase the lateral capacity and the lateral stiffness of the pile response. Evidence includes results from 1 g laboratory tests (Dührkop & Grabe 2008) and small-scale onshore field trials (Dührkop 2009; Dührkop & Grabe 2009). The improved lateral capacity results in significant cost savings through quicker installation and material savings as the required pile length (and/or diameter) is reduced. The shorter pile length implies the added benefit of rendering refusal during pile driving less likely.
