As a San Francisco skyscraper leans, a call for stricter building codes

San Francisco

A PANEL of experts said Thursday that San Francisco's building codes were inadequate to deal with the aftermath of a large earthquake and called for both the inspection and retrofitting of existing tall buildings and stronger regulations for new ones.

The assessment was delivered in a report commissioned by the city's former mayor, Edwin M Lee, and prepared by a group of engineers.

The report, which focuses on the seismic vulnerability of the city's growing collection of skyscrapers, comes as city officials are struggling to explain construction flaws in two high-profile new buildings. One of the tallest buildings in the city, the 58-story Millennium Tower, continues to sink into the ground and is tilting 15 inches toward neighbouring skyscrapers.

The report recommends that tall buildings be required to be more rigid and that critical infrastructure such as plumbing, water supply and electricity be built to higher standards.

No legislation has been written yet, but the report's recommendations will be presented to the city's board of supervisors later this month. If passed, they could be put into effect in the next revision of the city's building code in September 2019.

The driving philosophy of seismic building codes, which were conceived when most of the population in California lived in rural areas with lower-lying structures, focuses on protecting lives, not on whether a building will be usable after an earthquake.

A growing number of experts say the current building codes are not appropriate for modern urban areas that are much more dense.

"The building code is usually looking to make sure you survive the earthquake," Naomi Kelly, the San Francisco city administrator, said in an interview on Thursday.

"We want to go a step further - and make sure you can go back into the building."

The report calculated that buildings constructed to the current code could suffer damage that could take two to six months to fix. NYTIMES