Fagioli scales it up

The giant terminal processes natural gas near Porto Levante, Italy. Huge tankers (hailing mainly from Ras Laffan, Qatar) bring in liquefied natural gas, which the terminal returns to a gaseous state and pumps out through a 76cm-diameter subsea pipeline to the shore 15km (9 mi) away. When online in 2009, it will process 8bn cu m of gas, which represents 10% of Italy’s annual demand.

The structure measures about 188m long, 88m wide and 48m high. It is installed in 30m deep water, has a bottom and a top. In the bottom are two steel LNG tanks, total capacity 250,000 cu m, surrounded by a double concrete wall. On top is the regasification plant itself, control room and accommodation for 63 people. On the side are moorings for two LNG ships. The structure weighs 290,000t, and is ballasted with sand and gravel.

The entire unit was built in modules on a purpose-built quay in Algeciras, Spain, and then towed complete to its final position in August 2008.

The plant is owned by consortium Adriatic LNG, which includes Exxon Mobil (45%), Qatar Petroleum (45%) and Edison (10%). The general contractor of the EUR200m, three-year project was Aker Solutions, with civil construction contractor Acciona responsible for site preparation and gravity base structure construction, Fagioli for heavy haul and heavy lift, and mechanical contractor Dragados.

Gravity base foundation work began in 2005. Acciona built the concrete gravity base structure in a purpose-made basin. Three Liebherr EC-H tower cranes ran along each of the long sides of the structure, helping lift rebar and other loads. The largest crane on site was a 70m high Liebherr 550 EC-H 20 Litronic. Five 420 EC-H 16 Litronic tower cranes had heights ranging from 55m to 85m. Two smaller cranes, a 280 EC-H 12 Litronic with 70m jib, and a 200 EC-H 10 with 60m jib, ran on tracks above the basin feeding materials to the larger cranes.

Once the concrete shell was finished, Fagioli offloaded the steel tank sections, weighing up to 1,600t each, from the Blue Marlin, drove them down a ramp with 8% incline into the basin, and into the GBS via another steel ramp. Because the tanks float above the GBS floor, Fagioli installed 60 strand jacks on to the concrete roof, and suspended each section into position for nearly a month for final welding.

Topside

Once the insides of the terminal were finished, Fagioli was responsible for offloading, transporting and ultimately installing 11 modules, six pre assembled units and 100 other non-modular units on the top of the gravity base structure.

Fagioli used a site fleet of 200 self-propelled modular trailer axles, either separate or together in groups of up to 120, to move the offloaded components to a storage area about 700m away, and, when ready, transfer to final destination about 500m away.

“The main issue on every item has not been the weight and centre of gravity definition, but mainly the structural strength of the module during the transportation,” says Paolo Cremonini, director of operations and project management at Fagioli. “In fact, the actual SPMT configuration had to be defined not only according to module weight, centre of gravity and dimensions, but also to respect the strength of the module structure, verifying that the loads imposed by the SPMT’s bed was acceptable in any phase of transport and installation operations. And this required a great, deep and continuous interface with the client,” he adds.

There were two ways for lifting these loads on to the structure, which was 40m from the edge of the basin wall, and almost 25m higher than it. First, Fagioli re-hired two 750t Liebherr LR 1750 crawler cranes for the smaller single lifts, and for larger tandem lifts. One crane came from Austrian firm Felbermayr (in luffing jib configuration with ballast wagon), another from Sarens of Belgium. It lifted four topside modules, six pre-assembled units and 100 other structures with the crawlers.

The largest modular units were simply too heavy for even the large crawlers. For this job, Fagioli designed and installed an elevator. On the basin wall side, it set up two or three 30m-high lifting towers (depending on the lift) with two strand jacks mounted on top (600t or 750t capacity). Another pair of strand jacks hang, upside down, from their anchor blocks on steel beams protruding from the GBS support. Each strand jack holds up one end of a 40m-long, 3.6m wide and 2.2m high horizontal beam that spans the gap between the GBS and quay wall.

Each beam is itself a complex modular construction engineered to be used in diverse machinery moving and lifting operations, but also with pin connections for ease of assembly and transport by road or ship. The box sections were designed to resist twisting forces that might otherwise have required transverse supports. Fagioli had four beams on site. On top of the beams twelve 600t capacity skid shoes rolled the modules from the quay, on to the elevator, and then to final position on top of the GBS.

The elevator’s biggest load was the vaporisation module, a 4,800t behemoth that measured 75m long, 31.5m wide and 28.4m tall. Fagioli has also used its elevator system replacing a furnace boiler at Baosteel Shanghai, the first time that the top part has been moved and replaced in one piece. It will be used again for assembly operations of offshore platform Scarabeo 8 for Fincantieri Palermo, in Italy.

About 20 Fagioli employees spent about 18 months planning the first phase of the job; 12 people worked on the second phase with the elevator. During the operational phase of the job (November 2006–August 2008), Fagioli had on average about 30 people working on site, with a peak 60.

To comply with Exxon Mobil requirements, Fagioli staff worked to project-specific general procedures (there were more than 40), scenario-based risk assessments, and regular audits. Even minor lifting or moving operations required a safe job analysis and a toolbox talk. Site contractors operated a near miss reporting programme.

Representatives of every level of the construction project (client, main contractor and subcontractors) attended weekly site safety meetings. The planning and preparation seems to have paid off; during 22 months of site operations and 180,000 hours, Fagioli employees only suffered a couple of injuries, requiring no more than first aid treatment.