DESCRIPTION: Tri-Met upgraded the Portland and Western track and bridges to provide a commuter rail connection between Beaverton and Wilsonville, Oregon.
SERVICE: Foundation Engineering provided a geotechnical investigation and design services for rehabilitation of the existing track, replacement of five railroad bridges, replacement of three bridges with embankments and culverts, new retaining walls, a new operations center, five new transit stations, and new pavements. The project was completed using ODOT and AREMA design guides and standards.
The geotechnical exploration included 26 borings. Many of the borings required access along the active rail line, requiring coordination with the railroad and night drilling. Challenging foundation conditions included soft organic soils over hard basalt and long piles driven to bearing in stiff clay.
Foundation Engineering provided foundation design for multi‑span rail bridges ranging from ±150 feet to ±700 feet long. Construction included widening embankments up to 30 feet high and building new MSE walls up to 10 feet tall. We also provided services during construction including design of additional retaining walls, signal poles and construction observations for pile driving and earthwork.