Developed by Arup, the REDi™ resilience-based design guidelines establish a new benchmark for seismic construction--far exceeding current code criteria--that focuses on quick recovery and continued operations in the aftermath of an earthquake
Arup, the global design and engineering firm for the built environment, and Jay Paul Company, an award-winning real estate firm based in San Francisco, announce that 181 Fremont (the third tallest structure in San Francisco) has achieved a REDi™ Gold Rating, which will make it the most resilient tall building on the West Coast of the U.S. when completed. The 56-story mixed-use tower, built above five basement levels, is being constructed in compliance with a new set of holistic design and planning guidelines—the Resilience-based Earthquake Design Initiative (REDi Rating System)—that allow it to withstand the impact of a 475-year seismic event (roughly a M7.5-M8.0 earthquake on the San Andreas Fault) with minimal disruption.
REDi™ was developed by Arup with contributions from a diverse group of external collaborators. The system outlines holistic design and planning criteria within a resilience-based framework for architects and engineers to enable owners to resume business operations and provide livable conditions for tenants quickly after an earthquake. This goes beyond the building code's "life safety" approach which is intended to allow building occupants to exit the building safely but does not consider a building's functionality or even reparability.
"We sought to develop a blueprint for designers and owners who wanted to achieve higher resilience targets, with the ultimate intention to promote community resilience. This aligns with Arup's mission to shape a better world," said Ibrahim Almufti, SE, LEED AP, the leader of the development team for the REDi™ Rating System and Project Manager for 181 Fremont.
As part of the design verification for REDi™, Arup has also developed a methodology to predict the downtime of an organization whose buildings have been damaged by earthquakes. This has been utilized to estimate seismic risk for owners, hospitals, academic institutions, and corporations.
For 181 Fremont, Arup served as the structural engineer, geotechnical engineer, and resilience consultant on the project, shepherding the design team and owner through the resilience-based design process. This involved critical engagement with the developer (Jay Paul Company), architect (Heller Manus Architects), other engineering consultants, and the contractor (Level 10). The owners and designers pursued a REDi™ Gold Rating which included enhanced structural and non-structural design to limit damage, improved egress systems, contingency plans to reduce post-earthquake recovery times, and development of a tenant's resilience manual of recommendations to keep their space earthquake-ready.
These design measures helped reduce the expected repair costs by approximately 10 times compared to a code-designed building and in conjunction with contingency planning, reduces the expected functionality downtime from 18 months to less than a few weeks. As the structural engineer, Arup developed innovative design solutions to achieve these objectives, including the incorporation of viscous dampers (similar to vehicle shock absorbers) within the steel megabraces and uplifting megacolumns to significantly reduce the potential for earthquake damage. Not only do these measures significantly reduce seismic forces and wind vibrations, they also resulted in material savings of approximately 3,000 tons of steel and allowed the removal of a tuned mass roof damper (the common technology to mitigate wind vibrations for occupant comfort) which freed up the entire penthouse floor for occupancy.