181 Fremont

Structural Designer


Client Name

Jay Paul Company


San Francisco, USA

Level 10 Construction

Heller Manus Architects

Herrick Steel - Main fabricators
Taylor Devices - Supplier of damping systems
WSP - M&E engineer
Arup - Geotech consultant
Orlando Diaz-Azcuy - Interior design

Images: © Arup (1); Herrick Steel


The tallest mixed-use building in San Francisco. This 56-storey, 245m tall tower was designed for immediate re-occupancy and minimal loss of functionality after an earthquake and achieved the world’s first Resilience-based Earthquake Design Initiative (REDi) Gold rating.

Judge's comment:

Being in San Francisco, seismic considerations dominate the design of the lateral-load-resisting system. Viscous dampers have been used to absorb energy and control vibrations, buckling restrained braces act as structural fuses and limit loads going into columns, and an uplifting column detail is incorporated which controls the tension forces in the foundation.

The building is stabilised by a megaframe, split into a number of zones, allowing perimeter columns to transfer their load into corner megacolumns. This provides a column-free lobby and pushes the weight of the building towards the basement walls, simplifying the design of the foundation.

This concept has led to a virtuous cycle of material reduction which, together with the savings made due to detailed structural analysis, is reckoned to have saved some 25% of the weight of the steel frame - around 2700 tonnes of steel – enough to build a 20 storey building.
The judges were particularly impressed that 181 Fremont is the first building in the world to achieve a REDi Gold rating, being designed to remain essentially elastic and achieve immediate re-occupancy following an onerous earthquake event.

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Telephone: +44 (0)20 7235 4535
Email: [email protected]

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