Battle Stations

Austal USA nears completion of Mobile modular ship facility

The facility will be capable of building six large aluminum vessels per year, such as the Navy’s Littoral Combat Ship (LCS) and Joint High Speed Vessel (JHSV).

By Sam Barnes

Austal USA’s new $170 million Modular Manufacturing Facility (MMF) in Mobile, Ala., sits in an area that used to be part of Mobile Bay.

Austal USA will manufacture ship modules in the new facility. The modules will then be transported to a separate facility across the street that is already in operation.

The 100 acres of land were under water until the U.S. Army Corps of Engineers designated the site as a spoil area and began depositing dredge material there in the mid 1960s.

That’s why site preparation and foundation work were high priorities immediately after groundbreaking at the MMF site in July 2008. A 7 ft, 30-day surcharge was necessary to compact the foundation before other phases could begin.

Gray Construction’s Birmingham, Ala., office is managing design and construction of the facility, which will be capable of building six large aluminum vessels per year, such as the Navy’s Littoral Combat Ship (LCS) and Joint High Speed Vessel (JHSV).

Gray partnered with TranSystems Inc. of Kansas City, Mo., on the architectural design.

Austal will manufacture ship modules in the new facility, then deliver them by wheeled transport to a separate facility already in operation across the street.

“The facilities we’re responsible for building total 368,000 sq ft,” Gray Construction Vice President Chris Allen says. A future administrative building is also on the drawing board.

Large steel plate girders had to be installed in the high bay area to support a 250-ton bridge crane. Delivery of the massive steel girders by transport truck from Tampa Steel’s Tampa, Fla., fabrication facility was one of the biggest challenges of the project.

Engineers Thompson Engineering of Mobile and DEES Engineering of Gulf Shores, Ala., designed the foundation, and chose an auger cast pile system to accommodate the weight demands of the facility.

About 800 auger cast piles ranging from 50 to 70 ft deep and 18 to 24 in diameter were installed by Berkel & Co. Contractors of Atlanta, Ga. The foundation work was completed in September 2008.

“We were concerned about the groundwater (during the foundation phase) because in some locations the water table was just 1 ft down,” says Gray project manager Kevin Mills. “Some areas did get a little wet, but we just pumped the water into the onsite facilities.”

With the auger piles in place, and the potential for foundation-related delays in the past, the Gray Construction crew was then capable of “maintaining a steady work flow,” Mills says.

“We divided the building into five sequences. We started on the east end and worked toward the west end of thebuilding, basically finishing a sequence, then rolling out pier caps and piles.”

Representatives of Austal USA and Gray Construction, as well as other project leaders, gather to watch the placement of a large steel plate girder. The girders provide support for the building’s 250-ton bridge crane.

The largest of the footings and pile caps, measuring 19 by 25 ft, were necessary to support 138-ton steel plate girders in the plant’s high bay area.

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“Construction of the 100-ft high bay area was the highlight of the project,” Mills says.

The girders were needed to support the bay’s 250-ton bridge crane. Delivery of the steel girders was performed by transport truck from Tampa Steel’s Tampa, Fla., fabrication facility.

“The girders were placed on a specialized trailer using multiple steerable dollies, in the same manner that you would transport a bridge girder,” Mills says. “There was some concern that we would have to barge them in.”

Once at the site, the girders were offloaded and laid on their sides so they could be rigged for final lifting.

Three cranes were used during each lift, two to rotate the girder 90 degrees and lift it to a height of 85 ft, and a third crane to make final connections after the girder was in place.

Each girder measures 15 ft deep and 140 ft long and was lifted as a single member in May by Steel Performance Inc. of Greensboro, N.C.

Allen says about 8,000 tons of steel were needed for the project, with the entire steel package subcontracted to Cooper Steel of Nashville, Tenn.

During the installation of the building’s exterior skin, eight fabric doors measuring as large as 70 ft wide by 45 ft tall were installed. The doors, manufactured in Finland, can withstand hurricane force winds up to 135 mph, a necessity in the Mobile area.

A massive 138-ton girder measuring 15 ft deep and 140 ft long is lifted into place in May by Steel Performance Inc. of Greensboro, N.C.

Installation of the building’s largest bridge crane required that the contractor create an access opening in the high bay roof for the lifting crane boom.

“Due to the size of the openings that these doors must cover, fabric doors work better because they’re lighter and have less weight per square foot,” Mills says.

The doors have fabric on each sideand are supported by a lightweight truss frame, so “there is a lot of air space and less wind resistance.”

Inside the MMF, crews installed 14 overhead cranes, one in each of the facility’s 14 bays. The rail-mounted cranes range from 20 to 250 tons.

“The installation of the 250-ton bridge crane required an access opening in the high bay roof to support the lifting crane’s boom,” Mill says.

“We opened an access panel area to allow the crane operator to extend his boom through the roof, in order to successfully perform the lift.”

Other work required construction of a 2,000-car parking area, two security areas, and a 100- to 200-ft-wide, 10-in-thick paved concrete apron for the transport of the modules.

“When these modules are ready to come out, they’ll be placed on multi-wheeled transport vehicles and transferred to the assembly bay using the paved apron,” Mills says.

The electrical systems in the building were installed by Amteck LLC of Dyersburg, Tenn., and are capable of supporting up to 400 individual welders at one time. The heavy-load electrical system consists of heavy gauge conductors and high-rated panels.

In August, the Gray Construction crew and its various subcontractors were working on punchlist items.

From left, Chris Allen, second vice president, and Kevin Mills project manager, Gray Construction.

Gray managed about 250 workers at the peak of construction in late spring and early summer. Completion is expected this month.

Expansions at the Austal facility will ultimately accommodate a total workforce of up to 1,200 personnel in the new buildings.

“The design of this facility will be state-of-the-art and will greatly improve the efficiency and effectiveness of our production processes, thereby increasing our throughput,” says Austal USA CEO Bob Browning.

“This in turn allows us to offer a greater volume of vessels to our clients at increasingly competitive prices. We are also excited about the prospect of putting more local shipbuilders to work at Austal.”