SR1 Bridge over Indian River Inlet, Rehoboth Beach, Delaware

SEGMENTS, SPRING 2010, VOL. 55

As of February 2010, AECOM has completed the design of the new SR1 Bridge over the Indian River Inlet (Fig. 5 and 6) and Skanska USA Civil Southeast has completed approximately 50% of the construction. The Design-Build team started in September of 2008 and the new 2,600-ft. long cable-stayed bridge will be opened to traffic by April of 2011. Skanska is building the bridge from both sides of the inlet simultaneously. The project is currently on schedule.

All of the 36-inch square prestressed concrete pile foundations have been successfully driven to 1,800 ton capacity. All footings have been completed with column construction on-going. The four pylons are approximately 60% complete (150-ft. constructed and top out at 240-ft.). Each pylon will support 19 cable stays in a semi-harped arrangement. The pylons are being constructed in 18-ft. lifts using a PERI form system. Four sets of forms are being used to construct all of the pylons simultaneously. Two tower cranes are being used to construct the pylons and two additional tower cranes will be used to construct the superstructure.

The 400'-950'-400' cable-stayed superstructure spans are comprised of reinforced concrete longitudinal edge girders and transverse floor beams. Superstructure over land is being constructed on falsework with a combination of cast-in-place longitudinal edge girders and precast transverse floor beams. The floor beams are spaced on 12-ft. centers and cable stays are on 24-ft. centers. The portion of the 950-ft. long main span over the water will be constructed with a cast-in-place form traveler using the cantilever method of erection. Form traveler segments are 24-ft. long. Post-tensioning is used in all of the floor beams, in portions of the edge girders, and in portions of the deck. By the middle to end of June stay erection will be in progress, and cantilever erection with the form traveler over the Inlet will have started. The pylons are on schedule to be topped out by mid June.

The design-build team created a simple and slender structure that continues to be embraced by the community. As the structure takes shape, the design theme is being proven out: Maintain unobtrusive views of the Atlantic Ocean and don’t overpower the quiet beach community with a massive structure.

Project Details

Designer:

AECOM
 

Owner:

DelDOT
 

Bridge Design:

IBT
 

Design Build Team:

Skanska - AECOM
 

Contractor:

Skanska
 

Construction Engineer:

AECOM (Erection Analysis) and Finley Engineering Group (Falsework)
 

Construction Engineering Inspection:

 

Form Travelers for Cast-in-Place Segments:

 

Formwork for Pylon:

 

Post-Tensioning Materials:

 

Stay Cable Materials:

 

Structural Steel Cable Stay Anchor Boxes:

Cianbro
 

Bearings:

R.J. Watson and The D.S. Brown Company
 

Expansion Joints:

 

Prepackaged Grout:

 

Precast Producer:

 

Geotechnical:

S&ME
 

Wind:

RWDI