Much of the upland area within the terminal was created in different stages by placing fill on a tidal estuary, and constructing timber to retain the fill. The west bulkhead was constructed in this manner in 1949 and has a total length of about 1,300 feet.
The inboard side of the bulkhead is paved with asphalt concrete and is being used for parking and site access. The pavement is severely distressed, and some localized areas had been overlaid or repaired. The only major structure located in the immediate vicinity of the wall is a two-story office building (West Wall Building) that is located approximately 55 feet west of the bulkhead.
The northern 700 feet of the bulkhead was rehabilitated in 1989 to accommodate deeper draft vessels and address deterioration of the existing timber structural members. The south half of west bulkhead (southern 566 feet) has been in service in its present form for more than 50 years, and is in poor condition. As a result, the Port of Seattle retained PanGEO to assist the Port in developing design drawings to stabilize the bulkhead.
PanGEO completed a subsurface program to characterize the subsurface conditions along the wall alignment, and based on the subsurface conditions encountered, provided geotechnical engineering recommendations to assist the port of Seattle in design of a new steel sheet pile wall with tieback supports. PanGEO also assisted the Port in preparing the final plan and specifications and in providing construction monitoring.