Proj Overview

Project Overview

This three-mile, four-lane precast bridge, built over wetlands and a river, had to be built in 44 months. Moreover, the State Wildlife Resource Commission forbade in-water pile driving. The solution was the development of unique pile-driving erection gantry cranes that performed all construction and eliminated the need for an access trestle, all while partially suspended in mid-air. Two cranes were built to allow simultaneous construction from both ends of the bridge. Each was capable of working on three 120-ft spans at a time.

Precast Solution

As one span was completed and the deck cured, the gantry was launched ahead to begin pile driving for the next span. Concrete structural elements were precast off site and delivered as needed, reducing the construction site footprint. Work included driving 124-ft-long precast piles, erecting 50-ton precast bent caps, and erecting 121-ft-long precast girders. The erection system greatly reduced environmental impacts to the river, plants and wildlife. In addition, the project was completed on budget, seven months early. The project also won an Honorable Mention Harry H. Edwards Award for Industry Advancement.

 

Awards
2011 PCI Design AwardsTransportation Award: Best Bridge with a Main Span from 76 to 149 feet
Project Team

Engineer

Earth Tech Inc. (now AECOM), Raleigh, NC

Contractor

Flatiron – United, a Joint Venture, Firestone, CO 

Owner

North Carolina Department of Transportation 

Precaster

Coastal Precast Systems, Chesapeake, VA

Key Project Attributes

  • The development of unique pile-driving erection gantry cranes performed all construction and eliminated the need for an access trestle
  • Concrete structural elements were precast off site and delivered as needed, reducing the construction site footprint
  • The erection system greatly reduced environmental impacts to the river, plants and wildlife.

Project/Precast Scope

  • Deck area: 1,125,532 ft2
  • Bridge length: 15,247 ft
  • 1,227 30-in. square hollow precast piles
  • 922 precast concrete girders