Sharon Bernstein October 11, 2005
Tens of thousands of older concrete buildings across California represent the state's largest remaining risk of serious damage in a major earthquake, seismic safety officials say. Constructed as department stores, schools, parking structures and office buildings from the 1930s through the early 1970s, these buildings typically consist of large, open lower stories held up by unreinforced or poorly reinforced concrete pillars.
After several collapsed in the 1971 San Fernando earthquake, seismic safety codes were upgraded to require that any new concrete buildings be better constructed. Many seismic experts say preexisting structures - known as non-ductile concrete buildings - need to be retrofitted to bring them up to current standards.
"It's well recognized within the earthquake professional community that many California non-ductile concrete buildings are at unacceptable risk of collapse in moderately strong shaking," said Thomas Heaton, professor of engineering seismology at Caltech.Because many of the older concrete buildings tend to be filled during the day with office workers, schoolchildren or people parking their cars, the death and injury toll from an earthquake that caused several of the structures to collapse could be staggering, said Heaton.
But building owners and business organizations have long fought efforts to require retrofits, arguing that the risk is overstated. And they say that in some cases, the cost of retrofits comes close to that of razing a building and starting over. Neither the state nor local governments have required that the structures be reinforced.
"If you're going to use a 'sky is falling' scenario, then maybe you can justify" a retrofit requirement, said Carol Schatz, president of the Central City Assn. "But if you're going to put a bunch of commercial property owners out of business in the process, what have you accomplished?"
Property owners and business associations opposed a proposal last year by City Councilmen Greig Smith and Alex Padilla to count the number of unreinforced concrete buildings in Los Angeles. The measure didn't make it out of a council committee.
"We met with a lot of opposition," said Smith, who saw that and a companion proposal as first steps toward developing a program to retrofit the city's non-ductile concrete buildings and unreinforced parking structures. Smith said he hoped to work with business groups to draft a proposal acceptable to the council.
I know I am going to make a lot of people I know unhappy, but there are few things more important to the long term safety of LA than this issue. There needs to be an inventory our unreinforced concrete buildings and a study of just how dangerous each of them is.
But then both the state and the city need to get creative. There is not a one solution that fits this problem. Fixing these potential deathtraps will need to be done on almost case-by-case basis.
Possibly the adaptive reuse ordinance can allow for many of the larger office buildings to be turned into condos. Maybe zoning variances and property tax abatements might make it possible for the buildings to be financially able to be either retrofitted - or redeveloped.
I know even back in 1965 when watched the great American Cement Building being built on Wilshire overlooking MacArthur Park, I wondered how safe it was, a worry that only increased when I saw the damage done to concrete buildings in the 1967 Caracas earthquake. But now that it has been converted into lofts, possibly it can become a template of how to reuse these buildings, of course it might have been built to much higher standards than normal due to who its owner was.
Lastly, some years ago there was considerable press about 1970's and 1980's office buildings with unsafe steel welds not being retrofitted quickly enough; but I have not read anything on that story for many years. Maybe an update might be in order from Sharon Bernstein on that subject.
Was it done - or not done?
PS - Proof-readers. I think Sharon meant 'companion proposal' and not 'compasion proposal', so I corrected in my version of the story.