San Francisco: New regulations for retrofitting concrete buildings are underway

San Francisco city officials are actively engaged in retrofitting concrete buildings susceptible to collapse during seismic events according to the United States Geological Survey (USGS) projections that a minimum 95% likelihood of a damaging earthquake will strike the San Francisco Bay Area within the next century. Specifically, they have forecasted a 72% probability of a 6.7-magnitude or greater earthquake occurring in the Bay Area by 2043.

It should be mentioned that since 2013, San Francisco authorities have initiated a program resulting in the seismic retrofitting of over 4,500 multi-family residential buildings.  To continue that effort the Mayor of San Francisco, in collaboration with the Office of Resiliency and Capital Planning, has decided to develop legislation to establish a screening process for assessing the vulnerability of concrete buildings in the event of an earthquake. This process is to be completed by October 16.

Moreover, to stay ahead of potential seismic events, they have planned a 30-year strategy aimed at enhancing seismic resilience, known as the Earthquake Safety Implementation Program. This program includes developing retrofit criteria for concrete buildings within the city's building code

Due to an investigation, approximately 3,400 concrete buildings have been identified as potentially at risk due to the vulnerability of certain types of concrete structures, especially those lacking flexibility or steel reinforcements, which are naturally prone to crack and collapse during major earthquakes. However, to reach a definitive and ascertain if these buildings require retrofitting, an expert analyst explained that consultation with building owners and thorough inspections must be conducted first.

Nevertheless, the entire process, spanning from drafting legislation to executing seismic retrofits, is anticipated to be lengthy, with past retrofit projects averaging seven years, as highlighted by the Chronicle.