Going Mobile

International trade has sustained the city of Mobile, Ala., from its founding more than 300 years ago through the first decade of the 21st century. Located adjacent to a deep bay providing an ideal location for a port and harbor, the area’s early settlers received goods by ship from all over the world.

This beautiful Southern city of 190,000 has carefully preserved its past with grand houses and public buildings, while becoming one of the nation’s most progressive and livable modern cities.

Already established as one of the nation’s Top 10 shipping ports, Mobile significantly enhanced its position as a major port with the opening of the Mobile Container Terminal (MCT) in late 2008, increasing the port’s capacity to accommodate containerized cargo. The MCT provides access to global networks, covering all possible trade routes to and from the Port of Mobile.

The facility is a public-private partnership between the Alabama State Port Authority and Mobile Container Terminal LLC, a joint venture between APM Terminals North America and Terminal Link, a subsidiary of CMA CGM, a leading global container shipping carrier based in France. The facility is operated by Mobile Container Terminal LLC.

“The opening of the Mobile Container Terminal has made the Port of Mobile very competitive with neighboring Gulf ports,” said Brian Clark, the facility’s director. “The significant increase in capacity has encouraged additional steamship lines to add Mobile to their rotations.”

The terminal’s two giant cranes have changed the landscape of Mobile’s waterfront and, indeed, the city’s skyline, depending on the vantage point from which it is viewed.

The Post-Panamax ship-to-shore container cranes are capable of unloading or loading containers from ships too large to pass through the Panama Canal.

Each of the cranes is 240 feet tall and 90 feet wide with a 150-foot-long boom and a gauge of 100 feet, enabling it to reach across the width of 18 containers on board a vessel.

The cranes and other equipment installed during the first phase of construction have the capability to provide an annual throughput capacity of 350,000 TEUs (20-foot-equivalent units). TEU is the standard for describing a ship’s cargo-carrying capacity. A standard 40-foot container (40-by-8-by-8 feet) equals two TEUs.

Like most large cranes of this type, MCT’s models are electrically powered from the shore.

The general contractor for the $90 million project was R.B. Baker Construction Inc., Garden City, Ga. The electrical contractor was Bagby & Russell Electric Co. Inc., Mobile. The original bid-and-build contract for the electrical construction was for $6.5 million.

Albert Hensley, Bagby & Russell vice president and project manager, said work included electrical duct banks, vaults, distribution substations, 25-kV facility power and 15-kV crane power with a redundant power system for each crane, and high mast and perimeter lighting.

Electrical work began on Nov. 26, 2007, and was completed on time and within budget on Sept. 1, 2008, Hensley said. During that time, Bagby & Russell electricians worked 39,466 man-hours without a recordable Occupational Safety and Health Administration accident. Manpower was from Mobile’s International Brotherhood of Electrical Workers Local 505. During peak times, 33 electricians were on the project. The labor schedule was four 10-hour workdays with Friday and Saturday makeup days for time lost during inclement weather.

The two cranes are key components of the project, providing increased capacity of the Mobile port, and certainly they are the most visible. Their arrival by ship was itself a major event.

Manufactured in China, both were loaded onto one ship that sailed around the Horn of Africa to the Port of Mobile and off-loaded onto the rail system at the MCT.

“The off-loading was very interesting,” Hensley said. “The tide had to be taken into account, and the ship’s ballast tanks [were] flooded and flushed to keep the cranes from tipping over during the off-loading process, which took two days for each crane.”

Most cranes of this size are powered by electricity because it is more efficient. Electric power also is significantly greener than diesel power, which releases carbon into the atmosphere.

Once the cranes were in place, it was Bagby & Russell’s job to install redundant loops and main feeders to power them. Substations were mounted on concrete pads and include a primary switch, a transformer and a secondary distribution switch.

Hensley said the entire project is a fully grounded operation, with no component of the electrical infrastructure above ground. The project was designed to be completed in phases, beginning with underground work, followed by substations, cable pulling, termination and lighting installation.

“Conduit duct banks were installed first, so site paving could take place,” he said. “To support the fully grounded installation, all distribution cable was placed underground in 42 miles of PVC conduits. At just over 2,000 feet, the crane feeders were the longest. Substations for the cranes were installed adjacent to crane tracks.”

Power comes into the main substation from the utility company and then is distributed throughout the facility through underground duct banks and manhole vaults. Feeders arrive from the underground duct banks into the various substations for exact distribution for crane feeders, high-mast lighting feeders, and other areas.

“All power loops are redundant with two loops for each feed,” Hensley said. “If one feeder develops problems for whatever reason, there is another complete loop for backup, and the result is no interruption of normal services.”

Another subcontractor, R.J. Baggett, did excavation for duct banks with a large trackhoe, while Bagby & Russell installed all conduit and pulled all wire. Conduits were stacked in PVC chair supports horizontally and vertically, then covered by concrete for protection, and the surface was paved over.

“After underground work was complete, multiple crews of electricians worked simultaneously on other portions of the project,” Hensley said. “The whole underground system—vaults, duct banks and feeders—are like spokes from the hub of a wheel going out from the center to various locations and substations provided by Bagby & Russell.”

Each substation was lifted from a delivery truck by a crane and placed on the concrete pad and anchored to it.

To help keep the excavation phase on schedule, the 29 vaults were placed underground and prefabbed 20-foot sections of PVC conduits were stubbed into them and connected to the duct banks. Global positioning system (GPS) readings were taken of the vault locations, because the vaults later were covered by the concrete. Later, the GPS readings were used to locate the underground vaults, and concrete saws were used to cut through the paving to access manholes.

The crews of electricians were provided confined-space entry training for working in the underground vaults, and were trained and certified to operate the motorized Lull fork trucks used to move materials throughout the project site. Training included lockout and tagout procedures.

For termination of the 25-kV and 15-kV cables, a Tyco Electronics representative was brought on-site to train and certify Bagby & Russell electricians in order to meet factory warranty specifications of MV cable preparation for MV 5–35-kV heat-shrinkable terminations and splices and cold-applied splices.

High-mast lights consisted of 19 120-foot sectional metal poles, two 100-foot sectional metal poles and 21 60-foot sectional metal poles. Also installed were 1,000 watt fixtures, 10 for each of the 120- and 100-foot poles and two each for the 60-foot poles, with a total wattage of 252,000 watts.

“Installation of the light poles is routine for contractors experienced in this work,” Hensley said. “It is simply assembling sections of the poles, standing them upright with a truck crane, securing them to pole bases, and making terminations.”

For a project of this magnitude, Hensley said, work proceeded smoothly, and unexpected events were handled without causing a delay in completion.

The work schedule was interrupted just over a month before the target completion date when an oil spill on the Mississippi River closed operations at the Port of New Orleans. The cranes were powered up early to accommodate a ship rerouted from New Orleans. Areas in the construction zone were secured, and containers offloaded at MCT in order to keep the delivery of imported goods on schedule. The overall project work schedule was changed to six 10-hour days a week; after the Port of New Orleans reopened, the original construction schedule was resumed.

The high-mast lighting was needed for the opening ceremonies, but the completion of the substation to power them originally was scheduled in Phase 2. Bagby & Russell devised a reconfiguration of the substation feeders and moved forward to power up the lighting substations for the grand opening.

GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at up-front@cox.net.

About the Author

Jeff Griffin

Freelance Writer
Jeff Griffin, Oklahoma City, is a construction journalist specializing in the electrical, telecommunications and underground utility construction industries. Contact him at up-front@cox.net .

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