Design work by Horrocks began in 2009. Washington County Constructors, a joint-venture of Ralph L. Wadsworth Construction, Murray, Utah, and Granite Construction, Watsonville, Calif., was awarded the construction manager/general contractor contract and broke ground in 2010 after close coordination with the design team, the Utah Dept. of Transportation and St. George city officials.

Scott Wiscombe, project manager for the team, says the project was divided into four bid packages. The first one, for the steel girders, was released before official groundbreaking in May 2010.

The Dixie Drive Interchange plan is made of 13 significant components, which include six new bridges and channeling a portion of the Virgin River into a 700-ft-long, side-by-side box culvert topped with a pedestrian tunnel to connect the city's trail system.

In the new design, Dixie Drive will cross over the interstate through a single-point interchange and then continue to the east side and the Dixie Convention Center. While working over the freeway and building the new on- and off-ramps, constructors were required to keep two lanes of traffic open in both directions.

Space for the new interchange was tight, forcing the nearby Southgate Golf Club to relocate nine holes.

Flooding in late December (ENR Mountain States, Jan. 6) caused some delays, but Wiscombe says flood-control work done in the area in 2005 kept damage in the city and at the construction site to a minimum.

“We did get about 40,000 cubic yards of sand that washed down the Santa Clara River and got deposited around our site, so we had to move that out,” he says. “But we had minimal damage.”

Cabell says one of the greatest challenges of the wide-scope project so far has been coordinating between all involved parties, which include local businesses as well as the city and state.

“To have all this coming together in one spot and trying to tie it all together has made collaboration with the engineering and building team and owner all the more important,” he says.

Wiscombe agrees. “The coordinated effort between the city, state and designer has gone well,” he says. “We've had budget cutbacks, and we've been trying to save money, but the coordination has been the strongest part of this.”

The project is scheduled for completion in April.