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During the magnitude (Mw) 7.7, 1993 Guam earthquake, which caused significant damages to coastal structures throughout the area, X-Ray Wharf in the island showed signs of liquefaction and lateral spreading and seismically induced settlement up to 30 cm. The existing wharf is approximately 450 m long and consists of a combination of steel sheet pile bulkheads with a single level of tie-backs and steel sheet pile bulkheads with relieving platforms. Even though the damage to the wharf was not significant during the 1993 earthquake, it was found that the existing wharf would not meet the current two-level seismic performance criteria per the latest unified facilities criteria, (UFC) 4-152-01 (DoD, 2005, 2012). Among the various concepts evaluated to upgrade the existing wharf, constructing a new wharf in front of the existing wharf was found to be the most effective solution and taken forward for final design. A new sheet pile bulkhead wall approximately 10.7 m away from the existing sheet pile bulkhead will be constructed and the space between the new and old sheet pile bulkheads will be filled with improved granular backfill. Cement deep soil mixing (CDSM) was selected as the most cost-effective ground improvement technique to improve the granular fill and weak foundation materials. Construction of the new wharf is presently under way. The paper discusses the seismic design philosophy, geotechnical field investigation, site characterization, seismic analyses, and ground improvement design in an informative manner useful to practicing engineers.

The U.S. Territory of Guam is located in a seismically active region and has experienced several major earthquakes in the past. The 1993 earthquake, with a moment magnitude of 7.7, caused significant damage throughout the island. During that event, the existing Uniform wharf wall experienced significant seismically induced settlement and lateral spreading. The adjacent Tango wharf also experienced some damage. The damage at Uniform wharf was so great that the wharf became non-operational after the earthquake. Both Uniform and Tango wharves are being upgraded to meet a two-level design earthquake and seismic performance criteria. New king pile-sheet pile systems with tie-rods connected to vertical pile-supported anchor blocks were designed to upgrade the wharves. Backland liquefaction within the immediate zone behind sheet piles is mitigated using a stone-column ground improvement technique. Acceptance of stone column performance was based on frequent verification borings in the field as well as additional laboratory testing. Driven piles were investigated with a dynamic pile analyzer to optimize anchor pile length and develop pile acceptance criteria. The paper focuses on the seismic design philosophy, geotechnical field investigation, site characterization, seismic analyses, and ground improvement design. In addition, the paper also discusses construction challenges and how they were overcome.

Being one of America's premier seaports, the Port of Long Beach has embarked on an ambitious $1.2 billion Middle Harbor Development Program that involves expansion and modernization of two existing container terminals at Pier E and Pier F. As part of Phase 1, Stage 1 of the program, Pier D, which defines the western edge of the development, will be cut back to expand the Slip 3 channel to accommodate navigation of larger vessels. Active oil wells within the Pier D backland need to be protected and operational during construction. The subsurface materials consist of an old buried rock dike that subsided due to oil extraction activities. In order to achieve the maximum width of the Slip 3 channel while constrained by the presence of active oil wells in the backland, the Pier D cut had to be inclined at 1.6H:1V (horizontal : vertical) which is much steeper than typical submerged slope cuts. The steeper slope cut required a new secant pile wall as well as some form of ground improvement to soils below the rock dike and in areas outside the rock dike prior to dredging to ensure stability of the slope and to protect backland facilities. Due to the presence of the buried rock dike, jet grouting was chosen as the most practical and cost-effective option among the various available ground improvement techniques. This paper discusses the geotechnical investigation and site characterization associated with the design of the jet grouting improvement. This paper also presents the controlling jet grouting parameters developed from the test sections prior to production, the quality control monitoring, and the challenges faced during construction and how they were addressed to successfully complete construction of jet grout columns.

The Port of Los Angeles (POLA) commissioned a project to design and construct a deep-water Crude Oil Marine Terminal (COMT) to accommodate large and small oil tankers and barges. The proposed COMT will be the first deep-water oil terminal to be constructed in California since 1984. The marine structures were designed according to the Chapter 31F of the 2007 California Building Code (CBC 2007), otherwise known as MOTEMS (Marine Oil Terminal Engineering and Maintenance Standards). The project is located in a high seismic region. MOTEMS requires a two- level seismic design with corresponding performance criteria. In addition, the structures were also checked for the CBC 2007 building ground motion criteria. The subsurface materials were found to consist primarily of elastic silt with some clay and sand and also strong but localized thin layers of rock that were encountered at random depths. Several site factors, including the presence and randomness of the hard rock layers and deep waters at the proposed structure locations limited the potential foundation types that were considered suitable for the project. The design of foundations for various structures was further challenged by the high breasting, berthing, and mooring loads from the oil tankers and high seismic loads on the foundations for the unloading platform and trestles. Among the various foundation types evaluated, large-diameter steel pipe piles were considered the most preferred foundation option based on the cost and constructability. This paper addresses the geotechnical challenges associated with the project and measures that were taken to overcome these challenges during development of the project. Copyright 2010 ASCE.