Fabrication of Platform Cerveza
Authors: Walvoord James M. 
Published: October 2008

Cervesa's jacket dimensions are: a 260 by 350 foot base, a 952 foot height, and a loadout weight of' 26,000 tons. This makes Cerveza the world's largest single piece jacket ever to be fabricated and launched. It was fabricated at McDermott's Morgan City facilities in the same yard location as Cognac. Fabrication took less than two years.

At the onset, designers and fabricators accelerated fabrication by fast-tracing: Designing, preparing drawings for, and fabricating jacket sections in the order needed.

As engineers went to work designing, fabricators went to work gathering ideas from each of the many yard disciplines to find ways to build faster and better. The result was a systematic refinement of fabrication techniques. Ideas from all levels of the 1,000-person project force sparked discussions and re-evaluations, bringing about quicker, shop wise ways to get the job done.

Then designers and fabricators worked together to develop readily constructible detail designs for each jacket part, working from the top of the jacket down to the mud mats. Once the design of a component was complete, McDermott's fabrication shops and in yard pipe mills would fabricate it. By staggering design and fabrication and by tailoring each design to the yard capabilities, our fabrication schedule was improved. Items such as the following were some bigger time savers:Laminated timber was used for launching the jacket.In-stock or easy obtainable pipe was used in designing braces so the time between final design and brace fabrication was kept to a minimum.Constant outside diameter for jacket legs and skirt pile sleeves with joint cans being 10', IS' or 20' in length were used to standardize plate orders and provide flexibility in handling joint cans.Fabrication and dimensional control was accelerated by having typical joints with two-inch spacing between joining braces and keeping overlapping braces to a minimum.

Construction proceeded with the on-the-ground fabrication of the giant trapezoidal bents: the trusses framed by each pair of the eight main legs. The jacket's two interior bents were fabricated in two adjacent sections and separated 650 feet from the design top. A fleet of 24 cranes rolled up one of the 660-foot top sections on its side and set it perpendicular to the ground, lengthwise on the jacket skid way. Welders working 160 feet in the air hung conductor guide framings to receive the top section of the opposing bent, which was then rolled up and connected to the first, giving four-sided shape to the growing structure. Following the rollup and mating of the approximately 300- foot long bottom bent sections, the top and bottom tructures were joined, extending the jacket to its full length. The fabrication and rollup process was repeated for the pair of exterior bents, with one bent being rolled up and installed in three sections for greater facility. As final steps in the main structural assembly, the skirt pile sections were installed in four parts: two by modified rollup, and two by lifting and stacking.

During the entire fabrication phase, the Cerveza fast-tracking received some unexpected help from an often uncooperative source -- the weather.