Plan ready to move bridge joint to Narrows

April 3, 2007 

The state and a Texas-based moving company have at last come to terms on how to get a giant expansion joint, stuck at the Idaho-Washington border since March 17, delivered to the new Tacoma Narrows bridge.

The state Department of Transportation is ready to allow Big Boat Movers of Zavalla, Texas, to redistribute the 100-ton load onto a double-wide rig that will take up two traffic lanes and require constant escorts as it moves from Spokane to the Tacoma Narrows.

The state had not issued a formal travel permit by the end of the day Monday, but only because a few of the many restrictions on travel in King County had not yet been finalized.

“It’s imminent,” said Claudia Cornish, a transportation department spokeswoman. “We’re just waiting for a few more details from our traffic management people.”

The truck moved Monday for the first time in more than two weeks, but not very far.

Operating under a special, short-term permit, Big Boat Movers hauled the bridge piece about 10 miles to a Transportation Department maintenance yard east of Spokane where its trailers will be reconfigured to meet Washington’s weight-distribution requirements.

That will entail adding four short trailers, or “jeeps,” side by side at the front end of the configuration, increasing the rig’s total width to 16 feet, 5 inches and spreading the weight side to side. A standard freeway lane is 12 feet wide.

According to the terms of the permit, expected to be issued today, the truck will take Interstate 90 west from Spokane and cross the Columbia on the Vantage bridge. It will continue west on 1-90 over Snoqualmie Pass, cut south at Bellevue on Interstate 405, then head south to Tacoma on Interstate 5.

At Tacoma it will head toward the Narrows on Highway 16, cross the existing Narrows bridge and double back to the construction site via the 24th Street overpass.

The rig is expected to go no faster than 30 miles an hour.

The load will require at least two pilot cars at all times and, when in congested areas, three pilot cars and Washington State Patrol escorts as well.

In the Seattle-Bellevue area, it will be able to move only from 2:30 to 6:30 a.m. on Saturday and Sunday. In Tacoma, it will be allowed to move only from 11:30 p.m. to 6:30 a.m. Sunday through Thursday.

Double-wide loads are not uncommon, Cornish said, but they are usually permitted for short hauls only. She said she could not recall another double-wide load that has made such a long, continuous trip in the state.

Cornish said the truck could be on its way as early as Wednesday.

“He’ll have to go through the weighing process again,” she said. “If he meets the criteria, he expects to begin moving either late Wednesday, or early Thursday. There are a lot of ‘ifs’ in there.”

The expansion joints – a companion to the stranded piece is waiting in South Dakota – presented a difficult problem to movers not only because of their size and weight but also because they are so unwieldy.

During the past two weeks they have been compared to a wet noodles, motorcycle chains and giant slinkies.

The joints have to be flexible because they’ll be used to fill in the gaps between the new bridge and the fixed, 90-million-pound concrete anchorages on either end.

Because the bridge is a free-hanging structure, it moves slightly from end to end, like a mile-long porch swing. Changes in temperature can make it expand or contract; winds, earthquakes and even traffic will make it sway slightly.

According to Tacoma Narrows Construction engineer Dave Climie, a single loaded truck applying its brakes will be able to swing the entire structure an inch or so one way or the other.

The expansion joints are designed to compensate for those movements, expanding and contracting like accordions while maintaining an even driving surface for vehicles.

Once installed, they’ll be able to compensate for 56 inches of movement in either direction.

D.S. Brown, which manufactured the joints, required that they be held rigid during transport so they would not be damaged. That meant supporting them underneath with long rigid beams. But because they are so heavy, the size of the beam had to be limited to avoid getting the center of gravity too high on the truck.

According to a heavy transport industry consultant involved in the process, it was hard to find any transporter willing to take on the job.

“This got turned down by just about every heavy hauler in the country,” said the consultant, who asked not to be identified. “Big Boat was the only one who would touch it.”

Cornish said Monday that as soon as the permit is issued, the state will begin working on an advisory plan to warn motorists. “We will be doing our best to keep people off the road,” she said.

Local restrictions

Truckers moving the bridge piece will face restrictions on when they can drive the double-wide load.

Interstate 90: Spokane to eastern approach to Snoqualmie Pass: Daylight travel allowed; no day-of-week restrictions

Snoqualmie Pass: Mandatory pullovers for backed-up traffic, more pilot cars. Details still being determined.

King County: Restrictions not finalized. In the Bellevue-Seattle area, travel allowed only from 2:30 a.m. to 6:30 a.m. on Saturday and Sunday.

Pierce County and Tacoma to Tacoma Narrows: Nighttime travel only, from 2:30 a.m. to 6:30 a.m. Saturday, and 11:30 p.m. to 6:30 a.m. Sunday through Thursday

Rob Carson: 253-597-8693

rob.carson@thenewstribune.com

The Associated Press contributed to this report.

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