November 25 - SAL Heavy Lift has been chosen by Bilfinger to transport and install test piles and equipment for the Wikinger offshore wind farm's pile testing campaign.
The objectives of the test are to confirm the design of the wind farm foundation by testing the performance of the piles against static, dynamic and cyclic loads specific for offshore structures.
Immediately after returning from a project in Angola, SAL's main offshore installation vessel Lone was set up for the first phase of the pile testing campaign. Initial vessel mobilisation activities took place in Rotterdam in early September.
After further mobilisation and loading of project equipment in Rostock and Sassnitz, the vessel was ready to sail for the field. Lone was also fitted out with additional living quarters to accommodate the 75 persons necessary for the project.
The full test campaign comprises two phases with tests being performed at three locations. During the first phase, three sets of piles were driven at designated locations to required depths.
In the second phase, pile pull-out tests will be performed with the expectation of minimal movement of the piles. SAL explained that the purpose behind driving piles in sets of three is so that two outer piles can be used as reaction piles, while the pull force is imparted to the central pile.
In order to accurately install the three piles in one line, Bilfinger designed and constructed a purpose-built piling template as the spacing between each pile is critical to the successful outcome of the test programme, said SAL. The template weighs just under 175 tonnes, while the piles average 50 tonnes in weight and 35 m in length.
The installation phase has essentially concluded with all works at sea having been finalised. SAL Offshore will return to the project site with the vessel Lone in December for the second phase of the test programme.
Located 30 km off the island of Rügen in the Baltic Sea and covering an area of 34 sq km, the Wikinger offshore wind farm project will consist of 70 wind turbines, with a total capacity of up to 350 MW. Spanish company Iberdrola is developing the project, which is scheduled to being operations in 2017.