Work completed in year one of Tacoma’s Nalley Valley interchange project is just the calm before the storm. A major traffic shift this spring opens the construction floodgates.

“If you compared photos of Nalley Valley taken last January and today, you’d be amazed how much the landscape and the skyline has changed in just 12 months,” said Washington State Department of Transportation (WSDOT) Field Engineer Troy Watts. “We’ve done a ton of work, but there’s still a lot more to do.”

The project is on schedule and on budget, according to Watts. WSDOT awarded the $119.9 million contract to Renton-based Guy F. Atkinson Construction, LLC, in October 2008. Primary funding comes from the 2003 Nickel funding package. Total cost of the project is $183.7 million.

Freeway construction has transformed the Nalley Valley. Since starting in January 2009, the nearly 200 workers building the new I-5/SR 16 Westbound Nalley Valley interchange have made the following progress:

— Sprague Avenue ramps demolished

— New temporary eastbound roadway built

— 69 of 84 deep-bore foundation shafts drilled

— 51 of 77 towering bridge columns complete

— 28 bridge girders set

— Seven stormwater ponds dug

— 12,000 cubic yards of concrete placed

— 70,000 cubic yards of earth excavated

— 140,000 tons of gravel brought to the site

In the spring, westbound traffic moves to a new temporary westbound roadway, and when it does the 131,000 drivers who use the I-5/SR 16 interchange will begin to see the project take shape.

Atkinson Construction is building the temporary westbound roadway now. Shifting westbound traffic will allow crews to demolish the west end of existing viaduct, clearing the way for new roadways, ramps and bridges.

The westbound shift and demolition also closes the last Sprague Avenue exit, the heavily-used off-ramp from westbound SR 16 to Sprague Avenue. The ramp reopens in the fall of 2011 when the project is complete. A six-month closure of the Scott Pierson trail between 25th Avenue and Cedar Street is also scheduled to begin this spring.

“When the project is done, drivers will see the improvements are worth the inconvenience of construction,” said Watts.

The I-5/SR 16 interchange is one of Pierce County’s worst traffic bottlenecks. The project reduces congestion and improves safety by eliminating the traffic weave where vehicles from I-5 change lanes in order to merge onto SR 16 or exit at Sprague Avenue. Redesign of the Nalley Valley interchange is part of WSDOT’s ongoing congestion-relief effort in the Tacoma/Pierce County area.

For the duration of construction, motorists can expect traffic impacts including visual distractions, short-term and long-term lane and ramp closures, narrow lanes and congestion through the work zone.

View complete project information and photos online at http://www.tacomatraffic.com .