Atlas Copco High-Pressure Diesel Compressors Help Repair a Cracked Dam

Antwerp, Belgium – March 2, 2015: Atlas Copco Rental USA supplies 6 DrillAir ™ XRVS 1300 CD7 high-pressure diesel compressors to help with the installation of high tension tendons to pull dam back together

March 02, 2015

One of the 13 monoliths that make up the spillway of the Columbia River’s Wanapum Dam (Central Washington) developed a 65 feet long 2-inch-wide crack.

Fixing the crack required 16-inch boreholes through the dam into the bedrock to facilitate the installation of 61-strand tendon anchors. The dam would be further reinforced by installing post-tension anchors along its face below the water line. The project would require a large volume of high-pressure air.

Nicholson Construction was awarded the anchor contract and the work required up to 3,600 cfm at 350 psi in an extremely tight working space. Therefore, they chose six Atlas Copco DrillAir ™ XRVS 1300 CD7 high-pressure diesel compressors.

Air support to repair the crack

When the project is completed, 35 tendons will be vertically installed in the monolith piers, 77 vertical and angled bar anchors. Nicholson Construction project manager BJ Hepworth said, “This process basically stitches the dam together from top to bottom.”

The installation process requires many precisely drilled holes.

“Holes that size require so much air capacity that it really limits our options,” said Hepworth. “We don’t have room for many compressors in that narrow access. The XRVS 1300s we rented from Atlas Copco make it a lot easier to operate, because we need fewer units in the work area.”

The two companies have worked together previously. “We actually just came off a job at a nuclear power site with a similar setup using Atlas Copco compressors. We were more comfortable going with their compressors, since we already knew and trusted them.”

The Nicholson team was also familiar with Atlas Copco’s support:

“You can run into trouble whenever you’re working at jobs that require high-pressure compressors that size. These would need to be running 24/7 throughout the project, month after month ... We knew Atlas Copco would take care of all servicing and be there to help troubleshoot any bugs we might run into initially. Of all of the things that we need to worry about, it’s great to know that we don’t have to be concerned with the maintenance of the air compressors on this project.”

BJ Hepworth, Nicholson Construction project manager

The project, which started in 2014 and will be completed later in 2015, is scheduled in two phases:

The first phase was completed in December of 2014 and included installation of a portion of the tendons and anchor bars so the reservoir could be brought back to an elevation of 562 feet. This elevation allowed the dam’s two fish ladders to return to normal operations.

The second phase will be to return water levels back to elevation 571.5 and full generation capacity (1,092 MW).

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Atlas Copco is a world-leading provider of sustainable productivity solutions. The Group serves customers with innovative compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Atlas Copco develops products and service focused on productivity, energy efficiency, safety and ergonomics. The company was founded in 1873, is based in Stockholm, Sweden, and has a global reach spanning more than 180 countries. In 2015, Atlas Copco had revenues of BSEK 102 (BEUR 11) and more than 43 000 employees.


Specialty Rental is a division within Atlas Copco’s Construction Technique business area. It serves customers in the industry segments around the world with temporary air, nitrogen, steam and power rental solutions. The specialty rental services are offered under several brands. The divisional headquarters is located in Houston, USA.