Idaho Logger’s Invention Removes Brush for Remote Projects

CLEAN SHAVE Nordstrom first conceived the cutter in 1991, after logging efforts declined. A Kingston, Idaho, logger once blamed environmentalists for timber work shortages. Now, he can thank them for opportunities in a more prosperous career in brush and shrub clearance. In 1991, when the local logging market deteriorated, Dick Nordstrom developed a mechanical brush-cutter bearing his name. There are three units now in his fleet. Starting with a Caterpillar excavator 322BFC base, Nordstrom replaced the factory bucket with a custom-designed, 3-ton cutting head. Attached to the excavator’s 35-ft boom, the work-tool attachment includes a 480-rpm, 1,100-lb disc with 24 replaceable 61/2-in. blades. The 60-year-old Nordstrom says he has just signed a contract with Ground Force Manufacturing of Post Falls, Idaho, to sell cutters overseas. Each unit is priced at about $500,000. Operating in high and low modes, the 35-ft boom comes down on trees and stumps up to 16 in. in diameter. A 125-hp Caterpillar 3056 auxiliary engine powers the cutting disc, which rotates 270° side-to-side. With the boom swinging back and forth, the unit cuts a 70-ft-wide swath through brush as the tracked undercarriage creeps on grades up to 55%. - advertisement - Rather than stripping the land, the cutter shaves away brush and debris 6 in. above the ground, leaving light vegetation behind for wildlife. Northwest Machine, Coeur d’Alene, Idaho, converts the machines for Nordstrom. Rental cost is $450 to $1,200 per acre, depending on ground conditions. Nordstrom and his son, Jay, who manages field operations when the cutters are at work, found a list of willing clients in the Northwest. In Sun Valley, Idaho, a Nordstrom cutter recently carved a 6-mile-long, 140-ft-wide firebreak to protect the ski resort’s luxury homes and condominiums. Sun Valley fire chief Jeff Carnes estimates the cutting machine’s rental cost was less than one-tenth the $5,000 per-acre cost of hand clearing. A federal Bureau of Land Management grant included $48,000 for the brush cutter’s rental, plus $40,000 for other area fire work. Carnes says the 30-day project was completed in one-third the time it would take hand crews to work in hip-high brush. The cutter has tackled larger jobs in Washington state, where it recently chewed through 400 miles of brush for Avista Utilities’ maintenance crews.

Ninety-Year-Old Bascule Replaced in Four Days

Crews floated in and jacked a 1,400-ton, 188-ft-long, 35-ft- wide vertical-lift span into an existing 1,400-ft alignment over the Thames River in Connecticut on June 24-27. Cianbro Corp. had only 96 hours to install the new Amtrak railroad span before reopening the route to 36 daily passenger trains.

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The new movable span replaces a 90-year-old bunion-truss bascule that tilted on trunion bearings to open. “The bridge had a history of issues concerning its ability to open and close 1,600 times a year,” says James Richter, Amtrak deputy chief engineer for structures. “The trunion counterweight retainer bolts kept breaking.” The 2.5-in.-dia., 5-ft-long bolts had to be constantly replaced.

Moreover, the electrification of the railroad route in 1999 added several hundred thousand lb of dead load due to the overhead catenary system, contributing to the risk of the movable span getting stuck, Richter adds.

Amtrak

Amtrak A 90-year-old truss is replaced with a vertical-lift span.

Pittsfield, Maine-based Cianbro won the approximately $60-million contract in 2005 for the replacement span in New London, designed by HNTB Corp., Kansas City, Mo. The existing bridge piers, about 130 ft deep into sand and gravel, had to be expanded to support the new 200-ft-tall towers for the new vertical-lift span. To do that, crews installed four new 36-in.-dia. pipe piles down to bedrock, 180 ft deep.

Unexpected settlement and movement of the main pier up to 1.5 in. laterally, however, “caused considerable grief,” says Richter. “If it were not a movable span, it would not have been such a big deal.”

Amtrak called in Mueser Rutledge Consulting Engineers, New York City, to investigate. “We had disturbed the boulder layer and caused sand and gravel to shift,” says Richter. Cianbro hired The Judy Co., Kansas City, Kan., to pump some 1 million gallons of special grout through tubes around the foundations. “We had as many as three drill rigs and three grout pumps,” says Chet Muckenhirn, Cianbro project manager. “We had to enlarge the piers with reinforced concrete and did post-tensioning that wasn’t originally anticipated.” That extra work added about $13 million and eight months to the job, notes Richter.

The challenges did not end there. The installation of the new span originally had been planned for mid-June. But the contractor had to scrap the initial plan to cut the old bridge’s 4-million-lb counterweight into five pieces with diamond-wire saws before removing them with a barge crane. The wire saws could not penetrate a section of steel punchings shaped like “doughnut holes” and filled with concrete, says Richter. So the contractor removed 1.5 million lb of concrete with hoe rams to lighten the counterweight enough so it could be cut free and temporarily supported on the existing trunion bearings.

The removal of the 650-ton span and new installation “went like clockwork,” says Cianbro Vice President Lincoln Denison. Crews used a 1,000-ton barge crane to lift out the old span. The new lift span was jacked up about 32 ft, then slid over and dropped 5 ft into place with 1⁄8-in. tolerances.

Shortly following the installation, crews made the new span operational for full 135-ft lifts, says Denison. Cianbro avoided the $500,000-per-day fines that would have occurred after the four-day outage. “We will come in and keep removing the concrete down to the point where we can lift the ‘pork chops’ out,” says Denison, referring to the distinctive shapes of the main steel segments of the counterweight. This summer, Cianbro will finish building a protective fender system using recycled plastic and fiberglass reinforcing, says Richter