Surveying of Caisson’s for Gorgon Loading Jetty at Henderson
RM Surveys has been contracted by Leightons to survey the fitting of the topsides structures and the construction of the caissons being fabricated at Henderson for the Gorgon loading jetty at Barrow Island in the northwest of Western Australia.
The Saipem-Leighton Consortium has been selected to develop the $900 million Chevron Gorgon LNG Jetty and Marine Structures project. Construction commenced in 2011 on Barrow Island, 70 kilometres off the Pilbara coast of Western Australia. The loading jetty project is expected to be completed in 2013.
The jetty design utilises 56 concrete caissons that are being manufactured at the Australian Marine Complex in Henderson, south of Fremantle. These will then be transported to Barrow Island and lowered onto gravel beds placed at intervals on the sea floor to provide a support structure for the jetty.
The locally-manufactured caissons will avoid the traditional piled construction method, which would have required hundreds of steel piles to be driven into the sea bed. This will both reduce the construction time and eliminate the noise and vibration associated with driving piles into the sea bed. The jetty itself will be 2.1 kilometres long and consist of steel trusses 70 metres long supported by the 56 caissons leading to the loading platform approximately four kilometres from the shore.
The work being carried out by RM Surveys involves surveying during construction of the caissons. Each of the 56 reinforced concrete caissons weighs approx 3,000 tonnes and is 26m in diameter and 8m in height.