The Greater Changhua 1 and 2a offshore wind farms in Taiwan were provided a range of high-level engineering and design services by Mammoet-Giant who also assisted with the transport and integration of the jackets, ready for load-out.
Jacket foundations for the Greater Changhua 1 and 2a offshore wind farms are comprised of upper and lower jackets, where Mammoet-Giant designed temporary lifting lugs fitted to both the upper and lower jacket sections as they rolled off the production line.
These upper and lower jackets were sat on top of the custom support saddles – also designed by Mammoet-Giant engineers – which were used on the self-propelled modular transporters (SPMTs) to transport both upper and lower pieces between assembly stations. This method ensured a more efficient transportation process compared with other methods by reducing the time needed.
PTC ring crane
As part of this project, Mammoet’s PTC210-DS ring crane was deployed for the first time to Taiwan. The upper jackets, weighing 270t, were transported in turn around 100m from the storage area to the PTC crane, where they were erected so that the transition pieces could be fitted. A 750t crawler crane was used for the upending operation.
The lower jackets, weighing between 600t and 700t , were then also transported to the ring crane’s location and erected in a similar fashion. Then the upper jackets, now fitted with transition pieces, were lifted by the PTC and mounted on the lower jackets.
The lifting capacity of the PTC210-DS ring crane allowed up to four jackets to be assembled at once at the same location, fast tracking the assembly work. Finally, the completed jacket structures were lowered onto the SPMT/saddle combinations for transport to a storage area at the facility.
Transport of the jackets was conducted using the 96 axle-lines of SPMT in two 4-file 24 configuration, with two transport beams. The beams, measuring up to 24m in length, were designed to bear the pile stoppers, allowing the transporters to lift the full jackets using the SPMTs’ integral hydraulic suspension.
During the fabrication peak time, Mammoet tapped into its global network to make sure lifting equipment was available to meet short-term demands. “Mammoet-Giant has provided strong support during the fabrication of the first Taiwan-made jacket foundations for the Greater Changhua 1 and 2a offshore wind farms. The PTC 210-DS ring crane’s high lifting capacity, together with the engineering expertise and solutions shown by the Mammoet-Giant team have provided both time and cost efficiency for the operations,” comments Sing Da Marine Structure Corporation.