Seattle Ferry Terminal

(Seattle, WA)  Landau Associates provided geotechnical engineering and environmental services for major improvements and reconstruction of the Seattle Ferry Terminal, including replacement of the existing Terminal Building and the timber trestle. The services were provided to support the National Environmental Policy Act (NEPA) Environmental Assessment (EA) and preliminary design of the proposed $200 million terminal building replacement and trestle preservation project.

Landau Associates implemented a comprehensive field exploration and testing program, supplemented with a sophisticated geotechnical laboratory-testing program including cyclic direct shear testing, in order to characterize the site conditions. Poor soil conditions, including soils subject to liquefaction and loss of strength during a major earthquake, complicated the design. Seismic design studies were undertaken and advanced numerical analyses using FLAC software were conducted to assess the potential for lateral spreading because of liquefaction and the expected lateral loading condition that would be imposed on pile foundations supporting the structure. Geotechnical recommendations were developed for the design of deep pile foundations or drilled shafts to support the terminal building and trestle.

Sediment sampling was also conducted to assess the level of sediment contamination in order to develop criteria and recommendations for appropriate sediment handling and disposal alternatives. Landau Associates also contributed to the Hazardous Waste Discipline Report and the NEPA EA.