The Ko’olani Tower Condominium is at the intersection of Waimanu Street and Pensacola Street in Honolulu on the Island of Oahu, Hawaii. The project consisted of a new luxury high-rise condominium comprising of 46 stories and providing approximately 750,000 square feet of interior space with a recreation center and commercial spaces in the first five floors and a five-story parking garage constructed adjacent to the main tower.
The subsurface conditions at the project site generally consisted of fill materials at the ground surface underlain by soft lagoon al deposits. Coral formation interbedded with layers of coralline detritus were encountered below the lagoon al deposits. Based on the subsurface conditions encountered and the structural demands on the high‑rise building foundation and parking garage foundation, Geolabs recommended supporting the new structures by a deep foundation system consisting of cast-in-place concrete drilled shafts. Drilled shafts with diameters of 36, 42 and 48 inches extending down to depths ranging from 45 to 130 feet below the ground surface were recommended based on the structural demands of up to 3,500 kips per drilled shaft. The larger diameter and deeper drilled shafts were generally recommended for areas with relatively high column loads, such as the main tower structure. The project consisted of installing about 274 drilled shafts to support the building and parking structures. Geolabs observed installation of all the drilled shaft foundations and provided Special Inspection services.
Geolabs also provided geotechnical engineering services in support of the Auahi Trunk Sewer project by preparing construction documents to install 1,200 linear feet of 30-inch diameter gravity sewer line by microtunneling methods. The sewer line alignment traversed sensitive areas, such as Ala Moana Boulevard and the Ala Moana Drainage Canal, before discharging into the 69-inch Ala Moana Trunk Sewer. As part of the project, jet grout column supports were utilized to support the sewer line in the long term.