First Building to Receive a USRC Rating - Roseville City Hall Annex
The U.S. Resiliency Council® (USRC) was formed as a 501(c)3 nonprofit organization and launched in November 2015 to establish and implement a rating system for the performance of buildings in earthquakes and other natural hazards. The system is currently applicable to earthquake performance but the vision is for it address other hazards including wind, flood and blast. The USRC issues ratings, certifies practitioners and best practices, and technically reviews ratings shared with the public so its ratings are both credible and consistent.
Improving local community and regional resilience in natural and manmade disasters is a national imperative. Key to the success of this challenge is the need to understand the performance of the nation’s building stock in terms of safety, repair cost and recovery. The vision of the USRC is to make the public more aware of their potential risks in natural disasters, and provide them with information to make better-informed decisions on owning, renting, leasing and insuring properties, so that market forces will drive the building design, and procurement process toward more resilient building design.
The Roseville City Hall Annex is first in many ways. Not only is it the first building rated by the USRC but it also received the USRC's highest Platinum Earthquake Rating. Furthermore, it is the first precast building built for the city of Roseville. The project structural engineering firm Buehler and Buehler Structural Engineers is a founding member of the USRC and Clark Pacific, the design-build supplier of the structural and architectural precast, is a USRC sustaining member.
The City of Roseville had outgrown its city hall building and because of a lease signed with Sierra College to begin classes in January 2017, city planners had only 12 months to design, program, build and prep the building for occupancy. Other building systems had been explored, including steel and cast-in-place concrete, but the Precast Hybrid Moment Frame system was decided on because it gave the architect design flexibility for this prominent building that sits in the Roseville City Square. Also, the 4-story office building houses critical operations for the city and in the case of an earthquake city officials needed the reassurance that these mission critical services would be housed in a safe, resilient structure. This platinum award is the highest USRC award and validates the excellent performance expected of this building in its design level earthquake:
The level of performance associated with the USRC Platinum Rating is not something that every building can achieve, but this project met that high standard because of the following features and conditions:
- Safety – 5 Stars - Injuries and blocking of exit paths unlikely - Expected performance results in conditions unlikely to cause injuries or to keep people from exiting the building
- Repair Cost – 5 Stars - Minimal Damage - Repair Cost likely less than 5% of building replacement cost
- Time to Regain Basic Function – 5 Stars – Immediately to days - The expected performance will likely result in people being able to quickly re-enter and resume use of the building from immediately to a few days, excluding external factors
- What may appear to simply be an elegant architectural facade actually doubles as an extremely regular and redundant structural system providing enhanced yet economical performance.
- The structural system incorporates a high-performance precast hybrid moment-resisting frame that limited design level drifts to less than 1.25% and is designed to be self-centering after the design seismic event therefore eliminating residual drifts, limiting damage, and providing for reduced recovery time.
- Roseville, and the greater Sacramento region, has a moderately high seismic hazard (compared to the "high" or "extremely high" hazard in much of the rest of California) which provides opportunities to achieve high seismic performance with only a nominal, if any, increase in construction cost.
Link to a video for construction details and attribution of the project team: https://www.youtube.com/watch?v=eOr6Q301zbk