When the 1.8-mile SR 99 tunnel opens to traffic in 2015, it will rely on the strength of 1,450 precast concrete rings fabricated with pinpoint precision at a newly expanded plant in Pierce County.
Dozens of community and business leaders gathered May 15 at the FPS EnCon Precast plant in Frederickson to hail the collaboration that will create more than 130 jobs.
“Replacing Seattle’s Alaskan Way Viaduct with a tunnel requires expertise and resources from around the world, and a key portion of that work is coming together in Frederickson,” said Pierce County Executive Pat McCarthy. “My administration assisted FPS EnCon with its permitting, ensuring there were no delays in getting this job-creating project moving forward. It will be fun to think about Pierce County’s contribution to this incredible engineering achievement when we drive in the tunnel.”
FPS, an affiliate of global civil construction giant Dragados SA, signed an agreement with EnCon Washington, LLC to form FPS Encon Precast, LLC. Under their joint venture, the tunnel lining will be cured at the Frederickson plant, which was expanded in recent months to accommodate the work.
“This facility is the result of extraordinary collaboration among business and government leaders,” said Steve Harding, business development manager at Dragados USA. “We are grateful to Pierce County’s economic development and planning staffs for expediting our permit review so we can remain on time and on budget. We look forward to working with our business partners to build a world-class tunnel that serves a world-class region.”
Each tunnel ring is composed of 10 concrete segments that weigh approximately 37,500 pounds apiece. When the segments are connected, the ring has an outside diameter of 56 feet and will encase the double-decker roadway and provide resistance against external pressure.
“Each segment is poured and cured in Frederickson, but the process is the product of a true international partnership,” said Tom Pierson, president and CEO of the Tacoma-Pierce County Chamber of Commerce. “This is a great example of our region’s valuable role in the global economy.”
The molds for the concrete segments, the carousel to carry the molds, and the “flying bucket” to pour the mold come from France and China. Spain-based Dragados is the premier builder of tunnels in the world. The batch plant was purchased from Germany-based Wiggert & Co. Western Trailer, which is based in Idaho and has an office in Tacoma, is building special trailer sets to transport the segments from Frederickson to Seattle.
Segment production began in March. Project managers expect it will take 14 months to produce the 1,450 rings. Before the tunnel ring project, the 20-acre EnCon plant primarily produced noise walls and retaining walls for the state Department of Transportation, as well as commercial wall panels and deck panel products.