Cooper River Bridge Replacement Project

Owner: South Carolina Department of Transportation
Location: Charleston, S.C.
Cost: $540 million
Contractor: Palmetto Bridge Constructors, a joint venture of Tidewater Skanska, Norfolk, Va., and Flatiron Constructors, Longmont, Colo.
Designer of Record: Parsons Brinckerhoff, New York

Palmetto Bridge Constructors and the South Carolina Department of Transportation recently completed the $540 million Cooper River Bridge, which features North America's longest cable-stayed span.

The team had to design and build it to withstand a Category 5 hurricane, an earthquake measuring 7.3 on the Richter scale and any impact from some of the world's largest cargo ships.

Additionally, the Cooper River Bridge - known formally as the Arthur J. Ravenel Jr. Bridge - one of the largest design-build bridge projects undertaken in the United States.

The SCDOT has estimated that by using the design-build approach, it saved roughly $150 million due to the reduced time associated with this procurement method.

The design-build contract was signed in July 2001, at which point the final design began while PBC began to plan and mobilize for construction. Fieldwork began in April 2002 with the construction of drilled shafts.

Bridge-deck construction began in September 2003. By spring 2004, the towers were under construction and by midsummer of that year nearly one half of the bridge deck spans were completed. By mid-2004, the towers were completed.

The main span superstructure was completed in March, and the bridge was opened in July.

The 1,546-ft.-long main span hangs from two "diamond-shaped" towers, with 128 individual cables anchoring it to the hollow interior core of the 575-ft.-tall structures. The deck is approximately 200 ft. above the median high-tide mark.

The towers were built with cast-in-place concrete, while the main-span deck consists of structural steel framing and precast concrete panels constructed and barged in from Savannah, Ga. A latex concrete overlay is then applied over the precast panels.

Key to compressing the schedule was breaking down the project into five smaller components: the main span, Charleston interchange, Charleston high-level approach, Mount Pleasant interchange and Mount Pleasant high-level approach. Each segment had its own general superintendent, budget and schedule, while a management team at the corporate level managed resources and provided support across all five projects.

The team also took an innovative and flexible approach to sequencing. For example, the main-span team began building the bridge deck before completion of the two towers - an approach the Skanska team had utilized successfully on two previous projects in Sweden.

Like other federal-aid highway projects, the Cooper River Bridge contract required the contractors and DOT to provide on-the-job training opportunities. But the team took this requirement and incorporated it into a broader community outreach effort.

The project team recruited more than 80 unemployed and underemployed citizens. Approximately 62 of the recruits eventually were able to obtain journeyman status.