Indian River Inlet Bridge Rehoboth Beach, Del.

PROJECT COST: $149.9 million

The $149.9-million Indian River Inlet Bridge project in Rehoboth Beach, Del., will replace an existing bridge that is suffering from significant scouring, which has undermined bridge piers and exposed steel H-piles to salt water.

Skanska USA Civil Southeast of Virginia Beach, Va., began the design-build project last summer. In the fall, workers started driving prestressed concrete indicator piles. The company divided the project into two sections, with separate teams and equipment working on the north and south side of the inlet, with plans to meet in the middle.

The new bridge will entirely span the inlet, with no supports in the water to avoid future problems with scouring. The supports are spaced to allow for future widening of the inlet from 500 to 800 ft by the U.S. Army Corps of Engineers.

The design features two, approximately 250-ft, cast-in-place concrete high towers on each side of the 2,600-ft-long bridge with 152 single-plane cable stays. It includes a 950-ft clear span over the water, with 45-ft vertical clearance over the navigational portion of the inlet, and 1,700 ft of decking over land.

For deep foundations, Skanska is using 36-in.-sq precast concrete piles, with a 22-in. voided centers, selected for their high capacity. Substructure pylons, columns and caps are cast-in-place concrete. In the approach spans, Skanska will use 78 70-in. bulb-T girders with a cast-in-place deck. The cable-stay section will use precast and cast-in-place floor beams and a cast-in-place deck.

The bridge will have two 12-ft-wide travel lanes, 10-ft-wide outer shoulders, 4-ft-wide inside shoulders and a 12-ft pedestrian walkway.

Skanska will build a large portion of the flanking spans and the main span on temporary shoring to meet the aggressive schedule. Crews will use a traveler to build the main span across the inlet. The navigation channel will remain open through construction.

The new bridge should open to traffic in mid-2011. Meanwhile, the Delaware Dept. of Transportation will continue to monitor and inspect the existing bridge to ensure it remains safe for traffic.

Key Players

Owner: Delaware Department of Transportation
Design-Build Contractor: Skanska USA Civil Southeast, Virginia Beach, Va.
Design consultant: AECOM, Los Angeles
Design Consultant: International Bridge Technologies, San Diego
Precast Concrete Contractor: Bayshore Concrete Products, a Skanska USA Civil Southeast subsidiary, Cape Charles, Va.
Cable Stay Technical Support: Freyssinet USA, Sterling, Va.