Four massive cranes, each weighing 1,550 metric tons, arrive in Baltimore in June after a nearly two-month journey from Shanghai. Courtesy of Ports America
Baltimore’s Seagirt Marine Terminal installs four large cranes, the finishing touch on a new fourth berth that will service post-Panamax ships.
July 10, 2012—Four massive cranes arrived in Baltimore Harbor in June following a nearly two-month voyage from China, and were offloaded at Seagirt Marine Terminal’s new fourth berth, where final assembly and testing is expected to be complete in August. The cranes and berth are designed to service ships even larger than New Panamax dimensions.
The project is part of a deal reached by the Maryland Port Administration (MPA) to create a public-private partnership with Ports America. That partnership, called Ports America Chesapeake, has a 50-year lease to operate the Seagirt Marine Terminal. Constructing a fourth berth, dredged to 50 ft, was one of the elements in the public-private partnership agreement.
“The port had dredged to 50 ft deep in the approach channel, but they had not dredged out in front of the wharf because the land retaining structure couldn’t take the dredging,” says Tom Ward, P.E., S.E., M.ASCE, the chief engineer for Ports America. “That site originally was the dredge disposal site for the tunnel project under Baltimore Harbor, and they put in cylindrical steel pile caissons to hold the dredge material. Then they had subsequently built the Seagirt Marine Terminal on top of that. Where berth four was, there was just a line of caissons.”
McLean Contracting Company, of Glen Burnie, Maryland, was hired to construct the wharf and dredge the berth, with design work by Moffatt & Nichol, of Baltimore.
Because the caissons were only 36 ft deep and the project required dredging in front of the wharf to 50 ft, McLean suggested a change order to build the wharf on a new independent pile system and embankment, rather than attempt to reinforce the caissons. The move saved both money and time, Ward says.
“They essentially ignored the caissons’ strength and put in a pile-supported wharf and new embankment,” Ward says. “They also came up with a precast concrete modular design for the deck that took a little more time up front, but speeded up the project in the end. So the wharf project came in under budget by about 2 percent.”
Each crane weighs 1,550 metric tons and stands more than 260 ft tall. At full elevation, the massive booms are about 405 ft high. Each crane has four 8-wheeled gantry bogies at the base, traveling on ASTM 171 lb/yd rails on reinforced concrete girders. Beneath the rail girders are 30 in. square prestressed concrete piles, extending about 99 ft below datum on the waterside and 85 ft below datum on the landside of the wharf. The piles are spaced 8 ft 6 in. on center, with a capacity of 400 tons each.
“Then there is a whole grid of piles under the deck to support the deck as well,” Ward says. “The wharf deck is designed for 1,200 lb/sq ft live load, because that has to handle all the trucks, equipment, and sometimes stacked containers.” The deck piles are 24 in. square, placed on an approximately 12.5 ft by 10 ft grid.
The cranes—fabricated by Shanghai Zhenhua Heavy Industry
Company—have been unloaded and are ready for final assembly.
Courtesy of Ports America
The cranes—fabricated by Shanghai Zhenhua Heavy Industry Company—arrived with some assembly required. After the cranes were guided off the ship and lowered into place on the rails, the upper works must be lifted to the tops of the legs and secured with a complex bolted joint. Overseeing the assembly for Ports America are Javier Itriago, P.E., the project manager, and Jim Nightingale, the director of crane engineering, with engineering support from Parsons Brinckerhoff, of New York City.
“Once they are all bolted back together, they will plug all the electrical connections and other connections back together and put in the last segments of stairs that were across the joint,” Ward says. “Then they will begin the process of powering everything up and commissioning them.”
Although the cranes were erected in China, powered up, and tested, Ward says the long journey at sea could leave them in need of adjustments. Also, the factory in China didn’t have room to fully test the massive cranes.
“They hope to get them erect in the next few weeks and plugged into the shore power,” Ward says. “Then they will start running them in. We have performance tests that need to be done, endurance tests. They are a very modern, very fast, very large set of cranes. These cranes are designed to sustain 30 to 35 lifts per hour, with peaks to 40 to 45 lifts per hour. “
The new berth will give Baltimore the second berth on the East Coast capable of handling ships with a 50 ft draw, Ward says.
“As bigger and bigger ships get put into service, you get smaller ships—that are still very large, still post-Panamax—being shifted to smaller markets,” Ward says. “The biggest ships are always put in the market from Singapore to Rotterdam [the Netherlands] or Hamburg, [Germany]. And they displace the previous generation into the transpacific. And then they displace the previous generation to that into the transatlantic, and we’ll be ready for them.” (For more information on the changes that can be expected from the expansion of the Panama Canal, read U.S. Ports Should Ready for Panama Canal Expansion
and Ports Plan for New Vessels