A 57-story tower, 181 Fremont is the third-tallest mixed-use building west of the Mississippi River. It combines more than 435,000 square feet (40,400 sq m) of class A office space with 67 luxury condominiums on the upper floors and retail space on the first and seventh floors. Located in San Francisco’s East Cut neighborhood downtown, the building is one of two that connect to the city’s new Transbay Transit Center by a seventh-floor skybridge to the center’s elevated 5.4-acre (2.2 ha) park. Developer and owner Jay Paul Company teamed with Heller Manus Architects and Arup to design and complete the 800-foot-tall (244 m) tower. The team set out to develop a signature building that would offer the feel of Silicon Valley–quality office space with all the amenities of downtown San Francisco, including integration with the new transit hub.
A Resilient Design Approach: REDi
The San Francisco area is among the most earthquake-prone regions in the United States. More than 7 million people live in the metropolitan area, with more than 2.4 million of those living near the Hayward fault line, which runs east of San Francisco, through the East Hills of San Jose, Oakland, Berkeley, and Richmond. Referred to as a “tectonic time bomb” by the U.S. Geological Survey, the fault line could produce an earthquake of magnitude 7 or greater. The population density and value of development and infrastructure along the fault line put the San Francisco metropolitan area at great risk.
Historically, most high-rise buildings in earthquake-prone areas have been designed to life safety guidelines, which ensure that in the event of an earthquake, occupants can exit the building quickly and safely. However, such guidelines do not consider how quickly and inexpensively a building can recover from a seismic event and return to operation.
The Resilience-based Earthquake Design Initiative (REDi) Rating System was developed by engineering and design firm Arup and a coalition of external collaborators from academia, federal agencies, and the private sector with an eye toward increasing resilience to earthquakes. The criteria encourage delivery of buildings that enable owners to resume building operations quickly after an earthquake and that reduce the associated costs of building repairs. Elements addressed by the standard include structural and substructure capacity design, resilience and business continuity planning, safer egress, and other nonstructural and operational strategies to reduce earthquake risks for the building and its occupants.
Though pursuing REDi certification was not part of the original plan for the site, developer Jay Paul Company saw an opportunity to connect what was already a cutting-edge, resilient design concept to this new standard. “After reviewing the design concept with Arup, we found that we were already set to achieve REDi Silver,” said Jake Albini, director of real estate development at Jay Paul. “We felt that pursuing REDi Gold would not only help send a signal to the market that this was an innovative building, but it would also encourage [the design team] to get creative as the design process progressed.”
Starting at the Bottom: The Deepest Foundation in San Francisco
At only 15,000 square feet (1,400 sq m), the footprint of 181 Fremont forced the design and engineering team to think of new ways to build a slim, 57-story structure that could meet San Francisco’s seismic requirements.
In approaching this challenge, the design and development team started with the building foundation. The caissons for the building were anchored to bedrock 260 feet (80 m) underground—the deepest of any condominium tower in San Francisco. The connection to bedrock helps the building avoid settlement issues with the surrounding soil layers while still providing enough space for the foundation to move during a seismic event. The flexible foundation and resulting building skeleton helped create room in the structure for other resilient design elements despite the small footprint. The design team was also able to incorporate a new occupant evacuation operation (OEO) elevator system that includes seismically resilient guiderails and state-of-the-art elevator technology.
The focus on the foundation has helped 181 Fremont generate strong condo sales even as structural concerns have plagued other nearby luxury properties. The REDi designation also lends a level of credibility to the design elements, boosting buyers’ confidence that the building will, in fact, withstand seismic events and avoid subsidence issues.
Less Steel and Better Shock Absorption
The building’s high-strength steel exoskeleton, developed to withstand seismic shocks, also opened up the opportunity for the building to have a column-free floor plan, making the interior space more adaptable for prospective tech tenants and allowing increased natural light in the building. The building’s plumbing and electrical systems were also designed to absorb seismic shocks and move freely with the building during an earthquake, reducing repairs that traditional systems might face after a seismic event. Because of the building’s flexible steel skeleton, significantly less steel was required in the structure—3,000 tons less, enough to build another 20-story building.
Among the most innovative design elements in 181 Fremont, viscous dampers (similar to vehicle shock absorbers) were incorporated in the steel mega-braces by Arup, significantly reducing the potential for earthquake damage, as well as the impact of wind on the building. These dampers replace a traditional, bulky rooftop tuned mass damper. This freed up 7,000 square feet (650 sq m) of valuable roof space—enough to allow the development team to add a penthouse floor for occupancy. The penthouse residence was put on the market for $42 million.
Beyond Construction: REDi Owners and Tenants
The building’s approach to resilience began with construction, but also included guidance for 181 Fremont condo owners, occupants, and property managers to protect their spaces from earthquake damage. Beginning with the predesign phase, a team that included the owner, engineers, and architects met regularly to discuss structural and operational strategies to ensure that the resilient design included operational considerations ranging from backup utilities to tenant data protection and backup communications.
As part of the 181 Fremont development process, Arup also developed a tenants’ resilience manual, which includes contingency planning strategies and recommendations for how tenants can get their spaces “earthquake ready” to limit damage and downtime after a significant seismic event. Condo owners and building tenants also have in place emergency preparedness plans that include the ability to use emergency elevators designed to be operational immediately after an earthquake.
Value Creation through Resilient Design
In addition to pursuing REDi, Arup and Jay Paul reduced construction expenses through use of a lean-steel frame and created the opportunity for more revenue with the 7,000 square feet (650 sq m) of penthouse space. These design elements, and the value of resilience in attracting and retaining tenants and buyers, helped justify the cost of pursuing REDi Gold and inspired the developer to pursue REDi in future projects.
“If we do another tower project in San Francisco, we would never skimp on the foundation or structural engineering to withstand a seismic event,” said Albini. “[A]s a result, pursuing REDi again would be a no-brainer.”
While the innovative engineering design helped unlock cost saving and opportunities to generate revenue, the biggest life-cycle value of the REDi design elements is the reduction in repair costs and avoidance of downtime after an earthquake—not a focus of a traditional structure built to code in the San Francisco market. According to the models developed as part of the REDi process, 181 Fremont’s repair costs would be one-tenth those of a comparable building built to city code, potentially saving hundreds of millions of dollars in expenses after a major earthquake.
In conjunction with contingency planning from building management and occupants, REDi design elements would reduce the projected downtime of the building from 18 months to just a few weeks, which could collectively save tenants tens of millions of dollars in temporary relocation costs and even more in avoided lost work hours.
The design process also unlocked many opportunities that added considerably to the net present value of the building. Those include the following:
- The column-free floor plan, enabled by the exterior bracing system, allowed more-flexible, open, and light-filled floor plans that appeal to a wider range of potential tenants and allow a broader range of uses on every floor. This was especially important for Silicon Valley tenants, accustomed to large open floor plans that encourage cross-team collaboration and easy intra-office communication.
- The open floor plan is complemented by dedicated condo and office elevators, attractive exposed staircases, and the ability to incorporate light-filled, interior staircases into the office floor plans. These elements permitted design of a “vertical village” allowing several small tenants or one large tenant to connect office floors in a way reminiscent of the larger open floor plans in Silicon Valley.
- A design taking into account wind played a large role in 181 Fremont’s shape. The reverse chevron on the facade helps reduce the wind forces on the building, providing a quieter and more stable environment for condo and office occupants. The ship-like building design also helps connect all residents to the water—one of the most prominent and appealing aspects of the San Francisco experience.
Another element that could enhance the long-term business case for 181 Fremont is reduced earthquake insurance costs. Though the insurance industry lacks a standard method for working resilience into building valuation and the cost of insurance policies for the building owner, condo owners, and corporate tenants, this may begin to change.
After the REDi design and evaluation methodology was presented at a recent workshop, insurance brokers and underwriters for 181 Fremont said the design approach made them more confident of the building’s earthquake performance, justifying the possibility that 181 Fremont should see significantly lower insurance premiums than other buildings built to code nearby. If 181 Fremont does indeed see significantly reduced insurance costs, this could provide a near-term value to the building owner and tenants and help drive developers of future projects in San Francisco to seek REDi certification.
Marketing 181 Fremont
In 2017, Facebook Inc. leased the entire 436,000 square feet (40,500 sq m) of office space in 181 Fremont, constituting at the time the largest office lease in San Francisco in three years. Developer Jay Paul identified a number of factors that contributed to Facebook’s choice of 181 Fremont, including the building’s proximity to a major transit hub and the fact it provided a large enough space downtown to accommodate the firm’s anticipated growth.
Facebook and other prospective tenants also valued the column-free floor plan and the “vertical village” created by the interior stairwells connecting floors and teams, helping promote collaboration even in a space where floorplates topped out at 14,000 square feet (1,300 sq m) per floor. Facebook also valued the REDi certification, according to the development and leasing teams. Though lack of REDi certification would not have been a deal breaker for Facebook, the fact that critical data systems would be protected during an earthquake and that the building would be back online much quicker than others in the region helped make the business case for Facebook that 181 Fremont would be a good investment for a critical regional office, according to the leasing team.
The development team has also leveraged the building’s REDi certification in its marketing of the condominium units, highlighting resilience as part of the value proposition for the ultra-luxury residences. “Condo owners making a significant financial investment at 181 Fremont appreciate that the developer pursued methods to help protect the long-term value of their investment through an earthquake resilience strategy that focused on protecting occupants and reducing the cost of earthquake-related damages,” said Albini.
Brocher, Thomas M., et al., “The Hayward Fault—Is It Due for a Repeat of the Powerful 1868 Earthquake?” U.S. Geological Survey website, 2008, https://pubs.usgs.gov/fs/2008/3019/.
Loria, Kevin, “The San Francisco Bay Area has an earthquake ‘time bomb’ that could devastate the region—and it’s worse than we thought,” Business Insider, April 18, 2018, www.businessinsider.com/san-francisco-bay-area-earthquake-hayward-fault-2018-4.
181 Fremont Residences website, “Perfection from Inception,” https://www.181fremont.com/building?gclid=EAIaIQobChMIyaGYwOqj2QIVkw2RCh273gYDEAAYASAAEgKUUPD_BwE.
Jake Albini, director, real estate development, Jay Paul
Brian Swett, director, cities and sustainable real estate, Arup