Ramp SW Over I-5, Tacoma, Washington

SEGMENTS, SPRING 2010, VOL. 55

Atkinson Construction has begun construction of the Washington State DOT’s first precast segmental bridge (Figs 13, 14 and 15). Ramp SW over I-5 in Tacoma’s Westbound Nalley Valley Interchange Project was originally designed by the WSDOT as a steel box girder. However, high steel prices at the time of bid led the contractor to explore the feasibility of a concrete segmental bridge. McNary Bergeron & Associates performed the redesign, which features precast pier segment shells made integral with the columns by a cast-in-place diaphragm. The integral column connection is a key component of the design because of seismic demands.

The 1,060 ft. long superstructure consists of 112 segments, which are being precast off-site using the longline method. The maximum span length is 295 ft. and the deck is 43 ft. wide. Erection will begin in April 2010.

Project Details

Designer:

 

Owner:

Washington State Department of Transportation
 

Construction Engineer:

McNary Bergeron & Associates
 

Engineer of Record:

 

Formwork for Precast Segments:

Aluma
 

Post-Tensioning Supplier: