Port facilities require constant maintenance, repair and upgrades in order to handle the larger and faster ships that make up the world's naval and commercial fleets. Accommodating these vessels is not only big business for the ports themselves, but also for the region's contractors and engineers who work on these projects.
BAE Systems Ship Repair is the United States' leading non-nuclear ship repair, modernization and conversion company focused on dry dock and ship repair services for the U.S. Navy, other defense agencies and commercial customers. It has major operations in San Diego, San Francisco, Hawaii, and Norfolk, a facility that sits on 109 acres and features six piers.
BAE Systems' most significant project to date at its Norfolk Ship Repair facility is Pier 3, a World War II-era pier that had come to the end of its useful life. In addition to deteriorating from age, the pier could no longer adequately support the new classes of Navy ships that regularly pull into the facility for maintenance and repair. Demolishing the pier, however, was not an option.
According to Stephen Weber, P.E., structural engineer with Clark Nexsen, the original concrete pier deck sat on circular sheet pile cells. After driving steel sheet piles into the bed of the Elizabeth River, the cells were then filled with sand and a granular-type material. Timber piles were then driven through this fill to support the actual concrete superstructure of the pier.
"Over the years, significant corrosion has occurred in these sheet piles, and a lot of the fill has been lost as a result," says Weber. No longer completely buried by the sand fill, the timber piles have been eaten away by marine borers, a type of crustacean that is essentially a water-borne termite, and have further deteriorated due to exposure to higher oxygen levels.
"There were a lot of concerns about the cost of demolishing this structure and the permitting requirements," says Weber. "We ended up leaving the existing structure in place and using its concrete deck as the bottom form for the new pier. We built the new pier on top of that."
Of course, this meant obstructions were sure to be encountered, explains Jeff Fisher, P.E., structural engineer with Clark Nexsen. "We had to lay out the job so that we could drive the new piles in-between and around the existing piles."
"We did have drawings of the existing pier to work from, but as the contractor got into his work and started driving piles, he did run into situations where the existing structure was not built in accordance with the original drawings," adds Weber. "We had to make some adjustments to the design and layout of the piles, but it worked out great."
The first phase of construction began in July 2005. General contractor W.F. Magann poured a thin concrete deck on the existing pier to facilitate a bond break from the new pier as the old deck deteriorates, according to Eddie Goldman, BAE Systems Facilities-Drydock manager. "The 2-inch deck also provided us with a fairly flat work surface so that we could use the old deck as our bottom soffit."
W.F. Magann then cut holes in the pier and drove over 400 piles up to 120 feet deep for the new structure through the deck of the old pier. Four thousand cubic yards of concrete were then poured for the superstructure.
"As deterioration takes away more of the fill and some of the existing concrete, the new deck will be supported by the new piles that have been driven into an adequate bearing strata," says Weber. "It doesn't matter then whether the existing structure falls away."
Pier 3 is also home to the facility's 200-ton gantry crane, so building the new pier with the crane in place proved to be "one of the biggest feats of this job," according to Goldman.
After determining that dismantling and reassembling the crane would be too costly, engineers on the project decided to drive temporary steel H piles around the crane and jack it up out of the way. To do so, the crane was first rolled toward the offshore end of the pier. W.F. Magann then drove all of the piles at the inshore end of the pier, and then rolled the crane back. Using 2.5-inch all-thread rods with hydraulic jacks, a synchronized lift raised the crane 6.5 inches at a time for 5.5 feet. The crane was then welded to the piles.
"On the actual day we jacked the crane up, we started at 6 a.m.," says Goldman. "At 9:30 that night we had it lifted and secured; it was a 14-hour day."
With the crane jacked up, W.F. Magann removed the rails and poured the deck for the section of the pier directly underneath the crane. Once the new pier was finished, the crane's rails were reinstalled and the crane was lowered right onto its tracks.
Other improvements to the pier included moving all of the mechanical and electrical services for easier access.
"All of the mechanical and electrical services were up underneath the old pier," explains Goldman. "Access was always an issue. We'd have tide restrictions and confined space. Now with the new pier all of these services are up on top and access is now easy."
BAE Systems has also significantly upgraded the electric power supply from the pier from 4,000 amps to 8,000 amps in order to accommodate the new classes of Navy ships that have huge power requirements. These new state-of-the-art dry transformers run without oil so there is no potential for an oil spill.
The entire $9.3-million project has been under budget and ahead of schedule, which was no small accomplishment.
"The yard maintained operations so it was hard to do the pier work. I lost a lot of flexibility," says Bill Clifford, president and general manager of Norfolk Ship Repair. "I had to schedule all my work to make sure I had the piers available. It's a challenge when you have a lot of activity going on at a small, strong sturdy pier like Pier 4 (adjacent to Pier 3). It doesn't have a gantry crane, so when you're serving a ship on either side of the pier, you have to lock mobile cranes in. It's expensive, and as the crane turns you have to be careful. When you have a gantry crane that rides on tracks, it's very flexible, very fast and can service ships easily on both sides.
"For the past year it's been a real challenge to make sure I can keep all the ships serviced when I had a significant amount of my pier capacity tied up in this pier reconstruction, which couldn't impact the Navy or commercial vessels."
When Pier 3 is christened, it will meet the Navy's new pier strength requirements and host some of the largest ships in its fleet.
Across the river from Pier 3 at the downtown Norfolk waterfront is the city's new Half Moone Cruise Ship Terminal, a $36-million facility adjacent to the Nauticus National Maritime Center.
In the past, cruise ships in Norfolk have docked at the Navy Pier, which was originally designed for medium-sized naval vessels like destroyers or small cruisers to pull alongside the Nauticus National Maritime Center to allow tourists to visit the ships. Explains Stephen Weber, "The city of Norfolk began to delve into the cruise ship business and has tried to make Norfolk a port of call. Over the years they've added onto the existing pier to accommodate cruise ships. Currently they don't have much of a facility for loading and unloading passengers on the ships, so that necessitated the construction of a cruise ship terminal."
Construction of the cruise terminal was broken down into three phases. Phase 1 was construction of the new pier to support the terminal building. Phase 2 was construction of the terminal and ancillary structures, and Phase 3 was a small marina built on-site. Clark Nexsen designed the new pier in-house and, in conjunction with Florida architecture firm BEA International, assisted with the structural engineering and performed all of the civil, mechanical, electrical. and fire protection engineering on the terminal building.
Skanska USA Civil Southeast (formerly Tidewater Skanska) began construction on the pier in January 2005. Although the construction process was pretty typical according to Tom Fulton, project executive with Skanska, "it was a complex little project with a very tight schedule" that was complicated by the fact that work had to cease whenever a cruise ship docked.
Skanska began by driving 363 piles using conventional methods. "We used templates to support the piles during initial set and, in the case of batter piles, it was necessary to remove a 'plug' of soil below the mud line in order for them to be self-supporting until the hammer was set on them for driving. We used company owned floating equipment, and the majority of piles were in the 90-100-foot-long range."
Like the Pier 3 project, Skanksa encountered obstructions during the pile driving process.
"Years ago a pier known as the Banana Pier was built on timber piles because they were readily available," says Weber. "Consequently there is a forest of piles down there. Whenever you're driving piles in a site that isn't really a virgin site, there is always the potential for obstructions when you start driving piles."
There were a couple of change orders on the project as a result of the obstructions encountered while pile driving. The rest came from changes to the design of the pier that were necessary to accommodate the design of the terminal. Weber adds that there were many coordination issues because construction on the pier began before the terminal building had even reached 35-percent design submittal.
"Ideally the building design should have been completed before the pier design," says Weber. "We did it backwards because of construction schedule constraints. We wanted the construction of the pier to begin while the design of the building was ongoing. (Therefore,) as the pier was being completed the contract for the building was in place and the building contractor was ready tomove in."
Fulton adds that Clark Nexsen did a really good job of minimizing the impact of these change orders.
To facilitate the schedule, the entire platform was built of precast slabs. Once Skanska drove the piles, these piles then supported the formwork for the beams, which were poured in place and ran in two directions at 90 degrees, intersecting the piles. This resulted in a "criss-cross type structure" on which to set the precast slabs. The precast slabs also served as a stay-in-place form for the 7-inch concrete topping slab that completed the superstructure. Finally, 69 timber piles were driven around the perimeter of the entire structure to act as a fender system.
Another challenge for Skanska was the restrictive site.
"Of all the job sites I've ever worked on in this area, this one was probably the most restrictive," says Fulton. "Because of the tight schedule we needed so much equipment on the job that physically there was barely enough room. You could almost walk from one side of the line to the other across our equipment."
Getting employees and materials to the site also proved problematic. Employees had to park at a garage and get bused to the site, and barges were used for lay down room. Because the Nauticus facility continued to operate, the site also had to be kept exceptionally clean.
Despite these challenges, Skanska completed the pier on schedule in October 2005, and S.B. Ballard, the general contractor for the terminal building, was able to begin construction once the pier had reached 90-percent substantial completion.
S.B. Ballard is now nearing completion on the new Half Moone terminal facility, which will welcome its first cruise ship passengers in April.