A joint venture of Flatiron, Fred Smith Company, and designer ICE of the Carolinas has won the $449.9m Triangle Expressway Southeast Extension project in North Carolina.

It will add 6.6 miles of new highway and three new interchanges.

It’s the third contract for Flatiron on the Triangle Expressway.

Working for the North Carolina Turnpike Authority, the joint venture will first carry out design and preconstruction planning for the extension.

It will then design and build a six-lane divided highway to extend the Triangle Expressway from Rock Quarry Road in Raleigh to US 64/I-87.

The work includes:

• New interchanges at Rock Quarry Road, Auburn Knightdale Road, and Poole Road;
• 19 new bridges including some 1,600 feet of dual bridges over the Neuse River;
• Rehabilitating and widening the  I-540 bridge over I-87; and
• Realigning the existing Neuse River Trail.

Flatiron said the design approach includes an “over-under” direct-connector ramp for southbound I-87 to westbound NC-540 traffic. This will cut costs and speed up construction, the company said.

The team has also been able to design out 1.3 million cubic yards of planned earthworks.

Flatiron is currently constructing two other segments of the NC 540 Raleigh Outer Loop as the lead partner in a joint venture with Branch Civil.