Manitowoc Ringer to Install New Chicago Harbor Lock Gates
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February 25, 2011 – A Manitowoc 4100W S-3 Ringer crane has been chosen by Central Contractors Service of Chicago to install new lock gates at Chicago Harbor, Chicago, Ill. The lock replacement project is being handled by general contractor James McHugh Construction, who hired Central to provide the lifting power to get the new gates in place. The 300-ton-capacity Manitowoc ringer crane has a 140-foot boom, a total picking radius of approximately 72 feet, and a capacity-enhancing ringer attachment.
It was the most economical machine and would allow for better distribution of the point loading, according to Central, a member of the ALL Erection & Crane Rental Corp. family of companies since 1977.
The Manitowoc 4100W S-3 ringer was erected on the barge at the Iroquois Landing dockside facility in Chicago, Ill. The new fabricated gates, with a total weight of 180,000 pounds, were loaded up and the barge was towed by a tugboat to Navy Pier.
“When a crane must be mounted on a barge, the crane’s load charts are decreased because of the lack of a reverse force; in other words, a barge is floating on water, not set on firm land,” said John Martello, Central Contractors Service general manager. “The relative instability of a floating platform has negating effect on the load weight able to be picked. Adding a ringer and pedestals to a crane distributes loading over a larger area and can increase the lifting capacity dramatically. The ringer attachment on the 4100W was utilized to better spread the weight of the crane on the surface of the barge. Instead of all the weight of the crane being carried on just two tracks, the weight is distributed to 11 points. This allows point loads to be reduced.”
The 72-year-old Harbor Lock on Lake Michigan at the mouth of the Chicago River, owned and operated by the U.S. Army Corps of Engineers (USACE), has been deteriorating for the last 15 years.
“USACE required that the maximum list of the barge during the gate picks be no more than 2 percent,” said Ken Derry, Central’s crane operator. “The actual list during the pick was 0.00 percent. This number is amazing, considering the weight of the pick and its location on the water almost 90 feet away from the crane.”
The lift and installation of the first gate took place on December 2, 2010, and the second gate was set a week later. Both procedures went without a hitch, according to Central. The barge and crane were to be repositioned to set the final two gates in mid-January.
