While a 115 foot crane is extremely high, especially from the top of it, it’s not quite high enough to accommodate the neo-Panamax ships that are calling on the Port of Charleston. The solution? Raise the cranes another 40 ft.
With the construction phase of the Charleston District’s Post 45 Harbor Deepening Project in progress, more neo-Panamax ships will be calling on the South Carolina Ports Authority’s Wando Welch Terminal, making it necessary to raise the cranes to 155 feet.
“In August of 2016, two new 155-foot cranes were delivered,” said Ed Stehmeyer, project manager/design manager in the engineering department of the South Carolina Ports Authority. “We used the new cranes to lift containers that were higher up and used the shorter cranes to get the remaining containers. It was inefficient, but we made it work since it was somewhat infrequent. Once the Panama Canal opened it become more of a problem, so we got two more new cranes in March 2018 and why we’re retrofitting four of our existing cranes. Now, we can service any type of ship that comes into the Charleston Harbor.”
Raising of the cranes began in August 2017, with each crane taking approximately four and a half months to complete and costing approximately $4.5 million to retrofit, and is scheduled to be completed by January 2019. Two of the four cranes have been completed and are back in service, one crane is currently underway and one crane is left to retrofit. Compared to the one and a half years it takes for the procurement of a new crane and the cost of approximately $11 million, retrofitting makes much more sense.
The process of retrofitting the cranes is a relatively simple one. A self-propelled modular transport, which is a platform vehicle with a lot of wheels that can rotate 360 degrees, is used to move the cranes from the docks to the work area and back. Once the cranes are in the work area, the retrofitting begins.
“Think of the crane legs as your legs, what we do is cut the crane above their ‘ankle’ and below their ‘knee’ and we add a 44-foot extension in the middle,” said Stehmeyer.
One cut across the existing crane leg is made, it’s raised up on a jack system, and a 40-foot steel leg extension is welded into place, which will be part of its new leg. Crane stiffening, which includes placing diagonal bracing and portal beams, to make the cranes stronger is the final piece of the retrofit.
“There are multiple teams of welders and fabricators on-site and they will typically get two leg extensions installed in one day,” said Stehmeyer. “That’s not the final installation, but you’ll actually see it in place. Once the next two legs are installed, they slowly drop the crane down on top of them and, finally, start welding.”
While the process of retrofitting a crane might be easy, the process of prepping the work area where the cranes were retrofitted was not. Most ports will raise the cranes on the docks, but the Port decided that would be too much of an inconvenience to their customers, so they built a work area in the container yard. This consisted of installing piles and steel beams below the pavement to strengthen it so it could hold a 1,600-ton crane.
With the crane retrofitting nearly complete and the deepening of the Charleston Harbor Entrance Channel well underway, the Port of Charleston is ready for the neo-Panamax ships.