The 3.5-mile stretch of I-85 near Salisbury, N.C., has long been considered one of the worst highways in the entire state, with a 77% higher crash rate than anywhere else.
Anywhere from 60,000-80,000 vehicles travel the 55-year-old roadway on a daily basis, which was only built for a capacity of 10,000. The original road alignment was curved and extremely narrow, with shoulders 4 ft wide at best and nonexistent at worst. In addition, eight bridges were in need of replacment, including one over the Yadkin River, which has been declared one of the 10 most dangerous bridges in America by the federal government.
As if the condition of the road didn’t cause enough problems, this portion of I-85 also went through, came near or passed over a designated historic district, two wetlands and a pair of rail lines.
Accordingly, realignment was one of the primary goals of the roadway portion of the project. Flatiron-Lane and NCDOT also wanted to expand I-85 from four lanes to eight. The entire stretch also sports 12-ft shoulders on both sides.
The new alignment presented its own set of challenges, namely passing through some previously untouched, wooded areas. In total, 1.2 million cu yd of dirt had to be moved and replaced, according to Adam Mathews, project manager for Flatiron-Lane.
Roughly half of the replacement soil had to be imported. Concrete, on the other hand, was batched on-site, which proved a huge boon to project scheduling and traffic control, preventing a constant stream of trucks to and from the site.
With such a tight roadway and the bridge to replace, limiting traffic backups was paramount. Flatiron-Lane built out a series of side roads and a new interchange to keep things moving.
The only time crews had to detour vehicles was four nights while they were building the concrete girders for a new bridge over the existing freeway and rail lines—two for each side.
“For all of the work we’ve done, to only have four nights’ worth of detours is really something,” said Mathews.
Once the northbound side of the new bridge was completed in May, both directions of traffic were diverted there while work continued on the southbound bridge.
As of mid-September, Mathews said that Phase 1 is on schedule for completion in March 2013—almost nine months ahead of the original NCDOT schedule.
“We’ve been able to take almost nine months of the project timeline largely because we used a design-build process,” said Mathews. R&B