The Alaskan Way Viaduct is a section of State Route 99 that runs along the Elliott Bay waterfront through downtown Seattle. The original structure was damaged by the 2001 Nisqually earthquake and thus necessitated its replacement. The project consists of north and south end bridges with a tunnel in between. The half mile long overpass on the south end elevates traffic over many busy railroad tracks and leads into the tunnel going northbound.
Long Span - WF100G girders spanning 205’ long and weighing 254,500 lbs. were the longest prestressed girders ever produced at CTC at the time. In 2011, Concrete Products Magazine noted that these girders were “the longest precast/prestressed concrete girders delivered to date via a U.S. thoroughfare.” A high slump concrete mix was used that reached nearly 13,000 psi compressive strength.
Tapered WF girders - 34 girders were produced that taper from 74" high on one end to 100" high on the other end. These girders were used to create an aesthetically pleasing transition between the bridge spans utilizing the WF74G girders and the WF100G girders. With 26 inches of taper over 137 feet, these girders are truly unique.
Precast/Prestressed Girders – 114 (ea), WF74G Girders, 105’-176’ long; 34 (ea) WF74G-WF100G Tapered Girders, 137’ and 155’ long; 17 (ea) WF100G Girders, 205’ long;
Abutment Caps – 3 (ea), Abutment Caps, 17’ long
Solid Slabs – 4 (ea), 20” deep Solid Slabs, 174 SF each; 128 (ea), 12” deep Solid Slabs, 99 SF avg
Curbs – 4 (ea), 17” deep x 25’ long precast Curbs