Publish and Present
The Terminal 5 Berth Modernization project modifies an existing concrete wharf and adjacent berth to accept 18,000 TEU container vessels. As a part of the design process for the crane rail modifications, the Port of Seattle and the Northwest Seaport Alliance undertook a test pile program. After preliminary design, conventional analysis indicated that new structural piles would approach capacity and constructability limits for the site. The Test Pile Program (TPP) aimed to do in situ testing on representative piles to determine whether required design capacities could be reached and whether any project savings could be made via design alternatives. The tests included upland steel pipe piles and in-water prestressed concrete piles.
Several challenges existed within the project. Rapid Load Testing had not been conducted in this region before and as such additional work with local, state, and federal agencies was required to complete the permitting process. Noise and ground vibration monitoring was completed due to the presence of impacts to nearby sites. Concerns about effects on aquatic wildlife also led to studies in advance of the testing as well as hydroacoustic monitoring during the testing. The high-visibility nature of the work inherent in the site’s location required the integrated involvement of public affairs staff.
Despite the many challenges, the TPP’s results were positive. Increased pile resistances were observed compared to traditional analysis methods. The previously-untested high-strength, high-stress prestressed concrete piles performed well under hard driving. In-water noise levels were within required limits, satisfying the requirements of the various permitting agencies and providing new data for the industry. Terrestrial noise and vibration levels were within required limits set protect the public’s health. There are construction benefits and cost benefits from the TPP to the overall Terminal 5 Berth Modernization project as well as to other potential future projects.