The Seattle Monorail was only intended to be a temporary demonstration of a commercial monorail system for the 1962 World Fair in Seattle, Washington. 62 years later, the system continues to operate between downtown Seattle and the Seattle Center. This twin track, one mile guideway incorporates 150 prestressed beams.

The wheels of a monorail train ride directly against the top and the sides of the concrete guideway beams. To ensure a smooth rider experience, accommodation for curvature and superelevation had to be factored into beam geometry, and fabrication had to executed with tight tolerances. Guideway beams had varying horizontal curvatures, requiring a universal adjustable form. Straight beams used both pre- and post-tensioning, while curved beam used post-tensioning only.

PCI-Precast Concrete Producer:

Concrete Technology Corporation, Tacoma, Wash.

Engineer of Record:

Alweg Rapid Transit Systems, Germany

Structural Engineer of Record:

ABAM Engineers Inc, Tacoma, Wash.

Owner:

City of Seattle, Seattle, Wash.

Contractor:

Howard S. Wright, Seattle, Wash.

Key Project Attributes

• Fabrication of the Seattle Monorail had to executed with tight tolerances.
• The monorail was originally supposed to be dismantled after the World’s Fair, but the monorail currently still operates.

Project/Precast Scope

• 150 prestressed beams