News, City Council, Santa Monica, Earthquake

Seismically Hazardous Buildings To Be Identified

Posted May. 30, 2014, 12:00 am

Parimal M. Rohit / Staff Writer

City Hall will hire an engineering firm to create list of buildings made of concrete, steel, or wood framing and are at risk of collapsing in a major earthquake, thanks to unanimous vote by the Santa Monica City Council on Tuesday.

Accordingly, Santa Monica becomes the first city in California to compile a list of earthquake-vulnerable buildings and require those potentially threatened edifices to be retrofitted.

Degenkolb Engineers will partner with City Hall to identify buildings “that are potentially hazardous during and after a seismic event.”

The City Manager’s office was authorized by the council to negotiate and execute a contract with Degennkolb Engineers for $91,524.

According to City staff, the survey will look into buildings constructed before 1996.

“Buildings that were constructed prior to 1996 may sustain significant damage during a seismic event and the aftershocks that follow. In cases of moderate to major earthquakes, older buildings suffer the most damage due to failures in the building’s structural system,” City staff stated. “Santa Monica has many buildings that pre-date 1996 which may require seismic retrofit.”

City staff added while some buildings built prior to 1996 could have already been retrofitted, there are probably “many buildings that remain unretrofitted and may present a hazard to public safety.”

Engineers from Degenkolb and City Hall will look at five types of “older buildings” as part of the survey, including unreinforced masonry, concrete wall tilt-up, weak open front soft story, non-ductile concrete, and steel moment frame.

“Despite the effort of staff and building owners to retrofit buildings that fall into the five categories, there remain buildings that are not fully retrofitted,” City staff stated. “It is the goal of the City to identify these buildings to determine the extent and effect to public safety.”

City staff stated it does not know exactly how many buildings would need to be retrofitted, though estimates indicate 30 to 100 of each type of building exists.

There were 14 submissions for the City contract. Degenkolb Engineers was selected for its experience as a structural engineering firm. Established in 1940 and offices located in Los Angeles, Oakland, San Diego, San Francisco, and Seattle, Degenkolb Engineers “specializes in structural design and retrofit and has worked with several municipalities in the retrofit design of city-owned buildings.”

Less than 24 hours after the Santa Monica City Council’s vote, the 15-member elected panel in Los Angeles voted to compile a similar list of wood-framed buildings constructed prior to 1978 that are possibly vulnerable to significant damage in a major earthquake.

Los Angeles’ Dept. of Building and Safety will, at the City Council’s direction, take inventory of “soft-story” buildings. A soft-story building is one built atop a ground-floor parking garage.

In 1994, the Northridge earthquake reportedly destroyed about 200 soft-story residential buildings; one of those buildings claimed 16 lives after it collapsed.

Los Angeles officials anticipate it would take about a year to perform site visits of almost 12,000 soft-story buildings.