When evaluating levels of seismic retrofitting, it is at the discretion of the owner to what level of resiliency they desire for their building. At minimum, the seismic retrofit ordinances aim to make buildings safe enough for tenants to exit the building safely in the event of a large earthquake. This does not guarantee that the building will be habitable after an earthquake. For other buildings that would in fact need to be in operation after a large quake, i.e. hospitals, these buildings must be kept to a higher standard of resiliency.
From Los Angeles Mayor Garcetti’s “Resilience by Design” report, “Our building code is designed around a life-safety requirement that mandates construction that ensures a low probability of collapse in the worst earthquake. The code is not designed, however, to make it so buildings, while still standing, are also likely to remain usable after an earthquake. This report recommends a voluntary rating system to encourage building owners to invest in the resilience of their buildings so that they not only stay standing after an earthquake, but so that they also remain functional.”
One such rating system for evaluating how well a building will hold up in an earthquake is known as the United States Resiliency Council Building Rating System. Per the USRC website, “The USRC Building Rating System assigns one to five stars for three performance measures – Safety, Damage expressed as repair cost, and Recovery expressed as time to regain basic function.”
Every city should be concerned first and foremost about the safety of its residents, but secondly, they should want to make sure that the City would still be able to thrive after an earthquake. Would the residents be able to return to their homes and/or jobs after a quake, or will they move to an area of less seismic activity? Per www.fema.gov/building-codes, “If you live or work in retrofitted structures, you’re less likely to be injured during an earthquake. After the earthquake, you’re also more likely to have a home and a job to which you can quickly return. Businesses that use retrofitted buildings are more likely to survive damaging earthquakes and to sustain shorter business interruptions and fewer inventory losses.”