ForConstructionPros.com

Article

  

Featured Equipment Today Online Articles

Updated: November 9th, 2009 11:45 AM EDT

Liebherr Duty-Cycle Crane Speeds Shaft Construction on Portland's Big Pipe

Construction Equipment - Crane

Liebherr HS 895 HD crane
Environmental Services, City of Portland/Sue Bednarz, Jacobs Associates
The Liebherr HS 895 HD crane assists with the tremie slab pour at the River Street Shaft on Portland's Big Pipe project.

Shafts are being formed for an East Side Combined Sewer Outflow (CSO) project in Portland, Oregon. The CSO is designed to significantly reduce sewage and storm water overflows into the city's Willamette River. These shafts are being created by constructing a slurry wall and then excavating within. Excavation is carried out using a Liebherr HS 895 HD duty-cycle crawler crane fitted with clamshell bucket. Periodically a drop chisel was required to loosen highly consolidated sand/silt/gravel formations.

Seven shafts, ranging from 49 ft to 67 ft in diameter and ranging from 120ft to 160ft deep, are being built along the route of the tunnel. Construction on these began in March 2006, paving the way for tunnel boring to begin in May 2007. As of mid-November 2008, six of the seven shafts had been completed.

On completion of excavation, the crane is also used to support the construction and installation of rebar mats, as well as tremie concrete operations, before moving on to the next shaft excavation operation.

The HS 895 HD is the largest model in Liebherr's series of duty cycle cranes. It has a maximum rated lifting capacity of 220 tons and has a maximum main boom length of 276 feet. Maximum boom length when fitted with clamshell or dragline is 181 feet. The 12-cylinder MAN diesel engine generates 900hp at 1,900rpm.

Clutch and braking functions on the free fall system are provided by a compact designed, low wear and maintenance-free multi-disc brake. The drag and hoist winches use pressure controlled, variable flow hydraulic motors, with sensors that automatically adjust oil flow to provide max winch speed depending on the load. The winch can produce a line pull of 66,200 lbs.

1 2 next
E-mail This StoryE-mail Article Print This StoryPrinter Friendly