Case Study: Perry's Victory
Perry's Victory and International Peace Memorial was established in honor of those who fought in the Battle of Lake Erie during The War of 1812. It was on Lake Erie that Commodore Oliver Hazard Perry won the greatest naval battle of the war. This memorial is a doric column that stands 352' tall over Lake Erie in Put-in-Bay, Ohio. It has an observation deck at 315' topped with a lantern. It is one of the tallest monuments in the U.S., with only the Gateway Arch, San Jacinto and Washington Monument being taller.
The monument which is located on South Bass Island had been closed to the public since 2006 due to concerns with deterioration at the Observation Deck. The National Parks Service solicited bids for repairs to the deck that would require substantial scaffold. The scaffold system would need to provide access to the Observation Deck, Penthouse Level and lantern. In addition, the scaffold would accommodate the rigging of granite stone weighing up to 3,000 lbs. needed for the repairs.
UBS installed a Dual 6000 lb. capacity Personnel/Material hoist which was turned over for service on July 29, 2010. The hoist was offset from the main structure using specialized ties & brackets to allow for access to the Observation deck. The hoist allowed for workers to bring all the necessary materials to the Observation level and was over 350’ in height.
Consideration was taken with the design to prevent any displacement or deflection that would result in potential cracking of the existing granite cladding. Because of these concerns, UBS and the NPS ruled out any conventional scaffold coming from the ground. The seasonal changes on a conventional system could potentially see in excess of 3" vertical movement before loading of the Observation Deck therefore, standard ground based scaffold colutions were not an option.
The NPS & UBS decided to design a system that would be supported from the top of the deck & transfer loads back into the shaft by placing 4 concrete pedestals at specific locations on the Observation Deck. These pedestals would accommodate the systems loads which included potential uplift. Four aluminum trusses would wrap the Penthouse structure and cantilever beyond the Observation Deck. From the ends of these trusses, suspension rods where used to support a similar set of trusses that would make up the support platform below the Observation Deck.
The upper trusses provided support for a lantern scaffold, a monorail system used for removing and placing granite and a platform to convey concrete materials. The lower trusses provided a platform to accommodate workers performing the renovations.
The scaffold was installed during the summer of 2010 and the project was completed in 2011.