Seismic Design Criteria for Pile-Supported Wharves at the Port of Long Beach

The Port of Long Beach (POLB) acknowledged in the late 1990's that the continuous increase in container throughput volume would require establishing a consistent system of standards and guidelines for the design of container wharves to successfully execute the necessary capital improvement. The understanding of seismic requirements for design of pile-supported wharves has considerably increased during recent years. New and larger ships provided new challenges; new details and practices for the design and construction of wharves were developed and followed by new codes and guidelines for port structures. This work, however, was driven by different authorities, often not closely coordinated: Code Writing Authorities, Owners (Ports), and Consultants. As a result of the rapid development in this field, the resulting documents for the seismic design of wharves made their interpretation sometimes difficult. POLB recognized the need for uniform and port-specific guidelines and developed port specific Wharf Design Criteria. This paper specifically addresses the Seismic Design Criteria. They include Ground Motions and Performance Criteria, Geotechnical Considerations with particular attention to soil-structure interaction, Structural Design and Analysis Methods, and Seismic Detailing. These subjects are specifically adjusted for site-specific conditions in POLB, such as seismicity, foundation soils, construction practices and the requirements of the Port's Engineering Bureau, which had an important function in the development of the criteria. All seismic design and analysis procedures are based on displacement-based procedures. The development of the criteria was reviewed at various stages by experts in structural, geotechnical, and earthquake engineering disciplines. An experimental program verified the analytical assumptions. POLB's recent wharf construction experience confirmed the practicality of the construction details. It is anticipated that these Criteria will provide more uniformity, focus on design, quality assurance, and minimize construction costs, while providing better coordination between POLB's engineering staff and consultants.