BergerWorld: 3rd Quarter 2007

Located along the outer Apra Harbor, a deepwater port on the western side of Guam in the Marianas Islands, Kilo Wharf was constructed in 1987 to provide a facility for loading and unloading ammunition. Today the wharf continues to serve as an essential support facility to the U.S. Navy's operations in the Western Pacific Region, but is in need of an extension to provide adequate berthing facilities to support the new T-AKE multipurpose dry cargo/ammunition ship. KCBL, in association with Moffatt & Nichol, was recently retained by the U.S. Navy to prepare detailed designs for the $80 million Kilo Wharf Extension Project.

The extension will utilize caisson construction to satisfy a variety of difficult site conditions, bringing the overall berth length to 800 feet. Four new caissons will be built to form the wharf face; an additional smaller caisson will provide end fill retention; and a sixth caisson will be decked over. One of the existing mooring

dolphins will be re-floated, repaired in dry dock and then reinserted into the wharf extension. Because Guam is subject to frequent major earthquakes, KCBL's berth extension design included seismic upgrades using the U.S. Navy's displacement-based seismic design criteria to allow lateral sliding of the caisson wharf structure within prescribed limits. This evolved into a unique seismic upgrade, requiring the existing caissons to be partially excavated, and ballasted rock removed to reduce the inertial mass of the system. Apra Harbour is also subject to frequent typhoons, and KCBL designed the wharf to withstand strong typhoon winds up to 170 miles per hour and wave heights in excess of 20 feet.

The caisson also includes crane tie-down points within the deck structure, capable of withstanding the large forces exerted on the cranes during a typhoon. Construction of Kilo Wharf is expected to commence in 2008.