Monumental crane assembled for major install at dam

The US Army Corps of Engineers is preparing to replace a lock gate at Lower Monumental Dam.

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Two bystanders are dwarfed by the concrete "stop logs" stacked up on the trailing section of the crane's track crawler mechanisms. Each log, which will act as counterweights, weighs between 72,000 to 76,000 pounds. (Nov. 4, 2010)

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Parts of a huge, heavy-lift crane wait for assembly next to the downstream lock gate at Lower Monumental Dam. Five smaller cranes, three of which are shown, will be involved in putting together the large crane needed to replace the lock gate. (Nov. 4, 2010)

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Tom Walter, foreman for Dix Construction, walks beside the mast section of the Lampson Transi-Lift LTL-1200 crane. The 190-foot long section will be put into place behind the crane's 350-foot tall main mast. (Nov. 4, 2010)

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Workmen feed the crane's one-and-a-half inch diameter lifting cable onto reels in the center section, which also holds the control cab and motors. The cable is 13,000 feet long, more than two-and-a-half miles. (Nov. 4, 2010)

KAHLOTUS, Wash. -- Big jobs need big tools.

And when the job involves replacing a 700-ton lock gate, the tool is REALLY big.

In this case, it's a super-sized crane now being assembled at Lower Monumental Dam. The machine, a Lampson Transi-Lift LTL-1200, will play a central role taking out the dam's 41-year-old downstream lock gate and putting in its new replacement.

The repair is one of three major rehabilitation projects at dams operated by the U.S. Army Corps of Engineers on the Snake and Columbia rivers slated to start in December. The work will shut down river traffic through March of next year.

According to Jason Ekstein, Corps quality assurance representative, it took about 100 truckloads to ship the crane's components from Pasco, where Lampson has a field office, to Lower Monumental.

"What's impressive about this crane is not its height, but its capacity. It's capable of handling 1,200 tons," Ekstein said. "It actually takes five cranes to put this one together."

As he took visitors on a tour of the assembly site, Tom Walter, foreman for Dix Corp. of Spokane, the prime contractor, explained that the 180-foot-long mast section now on the ground "is just the back end of the crane." The machine's main mast will be about 350 feet long.

On Thursday, workmen were guiding the lifting cable onto reels on what will be the center section of the crane. The 1.5-inch cable, like the crane, involves large numbers. In this case it is 13,000 feet, more than 21/2 miles, long.

As the crane is being assembled, the new lift gate is getting close to starting its trip upriver to the dam.

Fabrication and painting of the new gate were completed at the Thompson Metal Fabrication facility in Vancouver, Wash., Corps officials said Friday. All three gate sections have been loaded onto a barge and will remain at a holding facility until the crane assembly is completed sometime next week.

The dimensions of the new lock gate match the machine that will be handling it.

According to the Corps, the new gate is approximately 88 feet wide, 84 feet high and 15 feet thick at the broadest point. It weighs approximately 1.4 million pounds, or about 700 tons.

The steel structure has been fabricated in three sections. The two lower sections contain mostly ribs and skin plate, while the upper one-third of the gate consists of a more complicated matrix of ribs, intercostals, girder web and plates.

The $13.6 million lock replacement is being paid for by funds from the American Recovery and Reinvestment Act, said Gina Baltrusch, public affairs specialist with the Corps' Walla Walla District office.

Andy Porter can be reached at andyporter@wwub.com or 526-8318. Check out his blog at blogs.ublabs.org/randomthoughts.

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