Seattle Transit Light Rail

Seattle, WA

Project Description

This project consists of 4 miles of elevated guideway from BoeingFiled to Seatac Airport. The superstructure is precast segmental, with a typical span of 120'. Spans were built using an overhead launching gantry. The box carried two rails, that were continually welded and directly fastened to the top of the precast box girder.

Owner

Seattle Sound Transit

Contractor

PCL Construction

Designer

IBT/Hatch Mott McDonald

Our Role

McNary Bergeron & Associates provided peer review of the erection gantry design, peer review of construction loads on the structure during construction, and assistance with developing the erection manual.

Total Contract Value

$100 million

Timeline

2005 - 2008

Construction Method and Specifications

A self-launching overhead gantry was used to erect the segments using the span by span method. Top down construction minimized impact on traffic and the sensitive environment.