181 Fremont

The 181 Fremont Tower is the third tallest building in San Francisco and arguably the most resilient tall building on the west coast of the United States. Arup employed a holistic resilience-based seismic design approach to minimize damage in a 500-year earthquake and to allow immediate reoccupancy after a seismic event, achieving a REDi Gold rating. Its iconic tapering form, small footprint, and location in the midst of the Transbay urban regeneration zone presented significant engineering challenges. Arup incorporated groundbreaking design solutions, including an innovative viscous damping system within the architecturally expressed steel megabraces and uplifting megacolumns, which significantly reduced seismic and wind demands and resulted in a steel material savings of approximately 3,000 tons.