RALEIGH — After two decades of extensive environmental study and public outreach, the N.C. Department of Transportation on Tuesday awarded a contract to replace the Bonner Bridge in Dare County.

DOT Secretary Gene Conti awarded the $215.8 million contract to the design-build team of PCL Civil Constructors Inc. and HDR Engineering Inc. of the Carolinas. The contract amount is $25.8 million less than NCDOT’s estimated cost to build the new bridge.

“We’ve spent 20 years working hard to make a new bridge a reality, and it’s exciting to reach this step in the process,” Conti said. “We look forward to starting construction on this critically important project, which will provide a safer, more reliable way for residents and visitors to get from Hatteras Island to the mainland.”

The existing Bonner Bridge was built in 1962 and has far exceeded its lifespan. In the past 10 years, NCDOT has spent $26.5 million rehabilitating the 2.7-mile bridge to address the deterioration that comes with age in its coastal setting. The bridge over Oregon Inlet has a sufficiency rating of four out of 100. That does not mean the bridge is unsafe; it means the bridge no longer meets the needs of today’s motorists.

To ensure the new bridge stands strong for decades to come, NCDOT required the three design-build teams vying for the contract to substitute stainless reinforcing steel for traditional black reinforced steel in much of the bridge. Stainless steel is considerably more durable and is not subject to the extensive corrosion typical of black reinforced steel in the harsh coastal environment where the bridge is located.

The department also required that the teams add special mineral and chemical mixtures to the concrete used to build the bridge to increase its durability. With these factors, NCDOT expects the new bridge to last more than 100 years.

Of the three teams, the department determined that PCL Civil Constructors Inc. and HDR Engineering Inc. of the Carolinas provided the best overall value for the project. The team had the lowest cost, anticipates completing the project sooner than its competitors, and requires minimal impacts to Bodie Island and the Pea Island National Wildlife Refuge.

Design work is scheduled to start in the next few weeks, with construction beginning in late 2012. PCL Civil Constructors is set to open the new bridge to traffic in spring 2015 and demolish the majority of the existing bridge in 2016. A portion of the existing bridge will remain in place and be transformed into a fishing pier.

For more information about the Bonner Bridge replacement project, visit www.ncdot.gov/projects/bonnerbridgerepairs/.