Structures / Maui Field – Gas Production Platform, New Zealand
- Jonathan G. Wright
- Reinhard Ludke
Earl & Wright provided Structure and Mechanical Engineering and Naval Architecture services for the design, construction, transportation and installation of a gas drilling and production platform located offshore, southwest of the North Island of New Zealand in a water depth of 354 ft. The platform is a 432 feet tall, self-buoyant, four leg tower measuring 70 ft. x 160 ft. at the top and 157 ft. x 160 ft. at the base. Cross bracing pipes and legs had steel wall thickness up to 3 ¾”. NIPPON KOKAN SHIPYARD Fabricated the 7,060 ton, 22 feet diameter flotation legs platform and piles in Japan. Structure design criteria includes sustained wind at 135 mph and gusts up to 163 mph and 73 ft. high storm wave heights. This active seismic zone required engineering for a 1000 year return period maximum credible earthquake, MCE. The 1973 seismic engineering of the Maui A Platform used a pioneering approach of static, non-linear, push over, structure model and analysis
The Maui Gas Production Platform structure engineering was a “self-floating” platform with 30 feet diameter bouyancy legs with water tight ballast compartments that allowed sequential controlled flooding to rotate the tower to vertical and lower onto the sea floor, engineering included fatique design of tubular joints, finite element models to determine stress concentration factors at tubular pipe bracing penetration through stiffened radial steel buoyancy legs. Seismic design included a static push over analysis through non-linear yielding of structure to reach a “collapse” mechanism.
- The gas produced at the Maui Field was used to power electric power plants that produced 30% of New Zealand's electic power.