CIVIL & STRUCTURAL ENGINEERING
• Removing marine growth is easier with limited numbers of submerged tubulars. • The main steel weight is between 10,000 tons to 20,000 tons per structure. Deck plating must be avoided to cut down the weight. The total steel tonnage for the example is about 100,000 tons to 200,000 tons. CONCLUSION Without question, an IFSF is a much cheaper option than an OFSF, but going offshore may be an unavoidable option in the future, if we wish to meet the 2050 net-zero target. This article does not compare the cost-effectiveness of our structure with that of an offshore wind farm. It should be evaluated by energy developers. The proposed structure is a simple, light-weight, less risky, certifiable offshore jacket structure. REFERENCES [1] Cheung Bob L Y (2021): ‘Design Economics of Multi-Purpose Offshore Wind Farms’, The Singapore Engineer, March 2021, 22-28, IES.
Figure 4: Details 1 and 2.
[2] Cheung Bob L Y (2021): ‘Design Economics of Trimaran Wind Turbine Installation cum Decommissioning Vessels’, The Singapore Engineer, September 2021, 28-33, IES. [3] Cheung Bob L Y (2022): ‘Design Economics of Infield Bridges for Offshore Wind Farms’, The Singapore Engineer, May 2022, 16-22, IES. [4] American Petroleum Institute: ‘Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms’, API RECOMMENDED PRACTICE 2A (RP2A) NINETEENTH EDITION, AUGUST 1, 1991.
Figure 5: Details 3 and 4.
with bigger housing facilities. We can provide a helideck for quick response. • Running anchor lines for the structure should be easier. Fewer lines 26
THE SINGAPORE ENGINEER January 2024
would be needed. The anchor chains can be very heavy. In an emergency situation, we can disengage all the anchors and tow the farm to a safe location.
[5] Cheung L Y and Foong K G (2008): ‘Design Considerations of a Loadout Skid Frame for a 14,000 tons Upper Hull Structure’, IES Journal Part A: Civil & Structural Engineering, Vol 1, No 1, 83-95, IES. (More information may be obtained from bob.cheung@rocketmail.com)