One of Chicago’s most attractive features is its 50km of Lake Michigan shoreline, nearly all of which is publicly owned.
The existing shore protection structures were built nearly a hundred years ago and, without intervention, about 18km of structures looked likely to fail, causing damage to $5bn-worth of infrastructure. The $301m Chicago shoreline project involves reconstructing revetment to prevent storm damage. Part of the shoreline project is the Chicago shoreline storm damage reduction Reach 2 – Irving Park Road to Belmont Avenue. The reconstruction of the existing shore protection structures requires the driving of 850 piles, each 16.5m long. This work was assigned to the subcontractor James Cape & Sons, which chose a Liebherr LR 883 Litronic crawler crane for the application with a hanging lead. The crane offers duty cycle capability with sufficient hydraulics to power a vibratory hammer. Primary requirements the crane had to meet were good lifting capacities and a strong line pull of 44,000lb (20t) on each main winch. An additional appeal of the LR 883, which is powered by a Liebherr engine providing 340kW at 1,900min-1, was that it needed no power pack for the vibrator hammer. All piling work is scheduled for completion for November but Liebherr says that Cape & Sons will beat this target as it has been driving 10 piles within a single shift.
