Port of Vancouver, Gateway T5 Bridge Design

The NW Gateway Avenue bridge is a 48-foot-wide, 400-foot-long, three-span concrete grade separation structure that spans several rail tracks. Approach fills are up to 34 feet thick and retained by Mechanically Stabilized Earth (MSE) walls. A second bridge about 150 feet long will access Terminal 5 from NW Gateway Avenue and will also span rail tracks. The project is partially funded by the Federal Highway Administration (FHWA) and was designed in accordance with the Washington State Department of Transportation Geotechnical Design Manual and American Association of State Highway and Transportation Officials standards. Project specifications used Washington State Department of Transportation Standard Specifications and special provisions. The geotechnical investigation included review of available geotechnical information for the site, subsurface explorations, laboratory testing, and engineering analyses. Geotechnical considerations included liquefaction-induced settlement and instability of the tall, MSE wall retained approach fills during a design-level earthquake, consolidation settlement at the approaches, foundation design, and design of a pavement section that meets FHWA requirements. Foundation support consists of 8-foot-diameter drilled shafts at the intermediate piers and driven pipe piles at the abutments. GRI provided recommendations for design and construction of drilled shafts and piles, retaining walls, approach fills, and seismic design considerations. GRI designed the stone column ground improvement for the tall approaches and abutments to reduce static settlement and the risk of excessive seismic-induced wall deformation. GRI also assisted with preparation of specifications and provided construction engineering services for the NW Gateway Avenue bridge. Construction-phase services included evaluating data from settlement plates and inclinometers that were installed to monitor the settlement and stability of the tall embankments.

Location: Vancouver, Washington

Owner: Port of Vancouver, USA

Market Sector: Transportation