181 Fremont stands as San Francisco’s third tallest tower (802 ft) and the second tallest mixed-use residential building west of the Mississippi. Engineers desired to reduce the weight of the initial design by implementing an innovation structural solution. FVDs were applied in parallel with the exterior BRB braces resulting in a damped mega brace system.  The damped mega braces dramatically reduced both wind excitations, particularly near the top of the building, and seismic forces. This was important to achieve occupancy comfort in the upper seventeen floors during windstorms.

In addition to reduced loading, this system allowed the building to exceed the California Building Code earthquake performance objectives for new tall buildings. 181 Fremont is designed to achieve immediate occupancy after a 475-year seismic event. The building sets the standard for “Gold” rating under Arup’s REDi System – resiliency-based guidelines.