When the 1.8-mile State Route 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 Wednesday 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. “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.
“We look forward to working with our business partners to build a world-class tunnel that serves a world-class region,” said Steve Harding, business development manager at Dragados USA.
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. 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 a leading 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 Washington State Department of Transportation, as well as commercial wall panels and deck panel products.