The 181 Fremont tower project provided unique challenges due to its tight job site and potential for settlement, and also demonstrates the important role of design build solutions to achieve time and cost-effective construction techniques. This 800-foot tower consists of 56-above ground floors. To resist seismic force, 5- and 6-foot diameter drilled shafts embedded into the Franciscan complex bedrock were framed into one 8 x 12-foot pile cap ring beam that encompassed the entire perimeter of the building. The deepest shaft drilled was slightly over 260 feet, and the longest rock socket was over 25 feet in length.
Below the tower is a 5-level basement, extending 60 feet below existing grade, and houses a loading dock facility and underground parking. A watertight, stiff temporary shoring system was required to allow the excavation to be performed without adversely affecting improvements on adjacent structures. Special bracing details were utilized at a shoring wall shared with the Transbay Terminal, to have a means of controlling the response to the 181 Fremont excavation.
Close, consistent collaboration between the all members of the project team was required to make this foundation project a success. In 2018, Malcolm and team members Brierley Associates (support of excavation designer) and Arup (structural and geotechnical engineer), won the coveted DFI Outstanding Project Award (OPA) for this project.
