Nearshore Pile Construction Experience in Burnie, Tasmania-Paper

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The paper describes foundation design and construction for the 2018–2019 upgrade of Toll Shipping’s Berth 4 in Burnie, Tasmania. The project added onshore structures and four marine dolphins to accommodate larger vessels, under a strict six-month delivery schedule.<br /><br />Onshore structures were designed with bored piles, while marine dolphins used driven tubular piles embedded in phyllite rock. During early contractor involvement, available 762 mm steel tubes replaced the larger specified piles, reducing procurement time and crane requirements. Because the smaller piles required impractically long embedment, the design was revised: piles were driven to refusal and rock sockets drilled beneath them. A pullout test on a trial socket supported increasing the assumed design skin friction, reducing required socket lengths.<br /><br />Construction encountered substantial unforeseen difficulties. Loose boulders and fill obstructed bored piling, forcing six ramp-abutment piles to be abandoned and the foundation redesigned as a non-piled beam. Unstable reclaimed fill caused ground collapse at the onshore mooring dolphin, prompting pile relocation. In marine works, down-hole hammer drilling made rock conditions difficult to verify and limited socket lengths on raked piles. The team developed safer sample collection and video-recording procedures and verified socket cleanliness before relying on end-bearing resistance. A ship also struck incomplete piles; after inspection, the design was revised to disregard their driven-section skin friction and rely on longer sockets.<br /><br />The project’s key lessons are to arrange targeted geotechnical investigations early, particularly in operational ports; involve the piling contractor in assessing construction methods and verification needs; plan for vessel impacts and operational constraints; and maintain flexibility to adapt designs quickly. Collaboration, extended work hours and timely design changes enabled completion on schedule.

Keywords

Berth 4 upgrade

Burnie Tasmania

foundation design

bored piles

driven tubular piles

marine dolphins

phyllite rock

rock sockets

geotechnical investigation

piling contractor collaboration