EarthquakesAfter the next Big One: How will San Francisco’s skyscrapers fare?

When Gregory Deierlein, the John A. Blume Professor in the School of Engineering and director of the John A. Blume Earthquake Engineering Center, looks at San Francisco’s skyline, he wonders: Will the city be ready if a major earthquake shakes those skyscrapers?

It’s not primarily a question of whether all the towers will remain standing, though there are some concerns about the ones built more than 30 years ago. The more complicated question is this, says Deierlein: If one or more high-rises suffers serious damage, how badly could that disrupt the rest of the city?

“Traditionally, the building codes for seismic design have focused on collapse safety and preventing the loss of life,” he says. “A full reckoning should also take into account the potential costs during the recovery.” For instance, a single damaged high-rise apartment building could force hundreds of residents out of their homes for months — bad news for a city that’s already notoriously short on housing. Likewise, an office tower that becomes temporarily unusable could cost the city millions of dollars in lost economic activity. And should a damaged skyscraper be at risk of collapsing, it would pose a danger to everything in its shadow. “What,” Deierlein asks, “would be the cumulative effects of this disruption on the health and welfare of the city?”

The city of San Francisco wants to know, too. In recent years city officials have been developing a sweeping new strategy on earthquake preparedness for skyscrapers, the first such effort by a city in the United States, and Deierlein and his team have been providing city leaders with hard data and new modeling tools to better estimate the costs associated with disruption and downtime.