Going Fast With GPS

Story By Carl Molesworth | September 28, 2010

Don't bother to look for survey stakes along the State Route 543 expansion project in Blaine, Wash. There aren't any.

IMCO General Construction, general contractor on the Washington State Department of Transportation project, has used Global Positioning System survey and machine-control equipment to do the job, saving time and money in the process.

"This contractor is very efficient," said Patrick Fuller, assistant project engineer for WSDOT. "You hardly ever see a piece of equipment that's not moving."

There are two U.S.-Canada border crossings at Blaine, which makes the waterfront town a busy place virtually year-around. The Peace Arch border crossing on Interstate 5 is the third-busiest passenger vehicle crossing on the border, while the Truck Crossing on SR 543 is the fourth-busiest commercial crossing on the border, according to WSDOT. More than 22,000 cars and 3,000 trucks cross through the Cascade Gateway every day, carrying about $31 million in daily trade.

Pressure to improve traffic flow at the border is intense. Backups at both crossings occur almost daily, and heightened security in the aftermath of 9/11 has only made matters worse. Adding to the pressure is the potential influx of visitors during the 2010 Winter Olympic Games in Vancouver, British Columbia. As many as 5,000 athletes and officials, 10,000 members of the media, 14,000 volunteers, and 2.3 million visitors will attend the games, and quite a few of them will be crossing the border to get there.

In response, WSDOT has instigated a series of projects on all of its cross-border routes. The SR 543 project will dramatically change and improve the mile-long highway by expanding it from the current two lanes to five and constructing a new interchange at D Street. It ties in with the Free and Secure Trade program. FAST allows for pre-approved trucks to quickly cross the border, much like Nexus, which is used by passenger vehicles. Currently, northbound trucks signed up for the program see little benefit because there is only one truck lane leading to the border station on SR 543. Once construction is complete, trucks using FAST will have their own lane, increasing their crossing speed while relieving congestion for everyone else.

Eliminating a Bottleneck

WSDOT awarded the $28.3-million contract for the project to IMCO, based in Bellingham, Wash., on March 13, 2006, and work got under way in May.

"Just getting this project to construction was a challenge," Fuller recalled. When bids came in over estimates due to the rising costs of materials, WSDOT had to re-evaluate and cut back on some aspects of the job. Fortunately, $500,000 in additional federal funding has come through to restore some of the aesthetic features, he said.

Plans called for the contractor not only to widen the roadway, but also to lower it 25 feet so that traffic will flow under D Street to eliminate the bottleneck there. Because of the inevitable backups created by vehicles waiting to cross the border, the decision was made to build three lanes northbound and two lanes for the free-flowing southbound traffic. The new northbound truck lane was shifted to the east side of the Duty Free Store to line up with the commercial inspection booths at the border.

Two lanes of traffic continued to flow through the center of the project as construction of the additional lanes began on either side. The sequence called for the new lanes to be built first, and then traffic will be diverted onto them while the old section of highway is cut down to pass under D Street.

To deal with the loose clay soils found on the project site, IMCO spent the first six months of the project drilling and pouring about 900 drilled shafts for retaining walls to prepare the site for the excavation of the lanes.

"This type of foundation construction is expensive, but it was required by the soil conditions," Fuller said. "We had to go down to 80 feet, and every other shaft has a steel cage in it."

With the shafts in place, excavation of the lanes could begin. This was when the GPS equipment really came into play, but the process was not made easier by the onset of a very wet winter season.

"We were battling muddy conditions all winter," Fuller recalled.

Construction of the D Street overpass is proceeding in a similar manner. The outer sections were built on "rat slabs" on top of the ground before the roadway excavation was completed. Then IMCO tunneled under the new bridge section to open up the roadway lanes below. Later, the center section will be built the same way.

Because of the extreme wear and tear that heavy trucks and buses cause on SR 543, the new roadway is being built with a concrete surface over a hot-mix asphalt base. IMCO subcontracted the paving to Acme Concrete Paving Inc., of Spokane, who brought in a massive two-lane paving machine to do the northbound lanes.

Other elements of the project include a noise wall, a wetland mitigation pond and two large water-retention ponds to process stormwater. WSDOT also is upgrading communications systems, with cameras and data-collection loops feeding into the department's website to provide travelers with real-time information on traffic delays at the border.

When construction is complete in fall 2008, SR 543 will move trucks and cars in a faster, safer manner to and from the border, WSDOT says. Extra lanes and the new D Street overpass will help separate cars and trucks and eliminate conflicts and congestion at intersections. Local Blaine residents will be able to cross SR 543 at D Street on the new overpass with no delay.

And when traffic picks up considerably during the three weeks of the Winter Olympic Games in 2010, SR 543 will be ready to handle its share.


Key Project Facts

Length of project: 0.8 miles

Cubic yards of excavation, highway: 194,300 CY

Cubic yards of excavation, retention ponds: 5,600 CY without concrete structural walls, 6,100 CY with concrete walls

Drilled shafts: 483 structural drilled shafts and 481 lean concrete shafts,

3 feet and 4 feet in diameter; 12,000 CY of structural concrete plus 2,873,612 pounds of reinforcing steel

Volume of concrete in the highway surface: 7,300 CY

Thickness of the concrete highway surface: 9 inches

Dowel bars: 11,500 MMFX 2 dowel bars for the Portland Cement Concrete Pavement.