Monday, September 22, 2008

'Incomplete' grade for school seismic safety

Still other school districts, such as those in Fremont, Berkeley and San Mateo, conducted top-to-bottom seismic reviews of their structures and successfully persuaded local voters to pass bond measures to pay for new or strengthened buildings.

The issue of seismic soundness of schools was brought to the world's attention on May 12 in China's Sichuan Province.

Classrooms were filled with students when a magnitude 7.9 earthquake damaged some 7,000 classrooms, their heavy fragments collapsing on those inside. An estimated 10,000 students died. This month, the Chinese government acknowledged the role of shoddy, rushed construction in the devastation.

While the staggering loss of young lives elicited outpourings of sympathy worldwide, many in California's earthquake belt may have taken comfort in knowing that the state has some of the most rigorous building codes in the world. While true, that doesn't tell the whole story.

Thousands of older classrooms, gyms and cafeterias were constructed before 1978, when a new building code took effect that corrected deficiencies.

Susan Tubbesing, executive director of the Earthquake Engineering Research Institute in Oakland, said it's a "really common misperception" that California schools would never collapse the same way schools fell in the China quake. "And we have to do something about it," she said, "because our schools are at risk."

Tubbesing said California public schools in general are among the world's safest due to a lauded construction standard called the Field Act, passed in 1933, that aims to keep school buildings standing and able to serve as shelters and staging areas for emergency crews immediately after a major quake. But evolving research has shown that the strongest quakes could leave some older Field Act schools in rubble. Codes with additional protections were added in 1978 and 1997.

The 8,000 California school buildings identified in 2002 as possibly being at risk for collapse were built between 1933 and 1978. According to the report, these schools are urgently in need of evaluation. If they fail a review, districts need to either retrofit or demolish the buildings.

Many of these buildings are made of concrete and inadequate levels of steel reinforcements. They're called "non-ductile" by engineers because of their brittle, unyielding material, and they're vulnerable to complete failure during major quakes.

In addition, many building types on the state inventory are listed due to flimsy connections between their roofs and walls.

"One rule of earthquake engineering is you tie everything together well," said David Bonowitz, a San Francisco structural engineer and a committee chairman with the National Council of Structural Engineers Associations. "Things fail where they connect."

Another roughly 2,000 older school buildings listed on the inventory, while expected to hold up during a major quake, nonetheless needed a check for how well the "non-structural" components — such as lighting fixtures, windows, ventilation equipment and bookshelves — were anchored. These falling objects could also kill and injure during a temblor.

"Your safety in an earthquake is a function of what falls on your head," Bonowitz said.

Added up, those 10,000 classrooms, gyms, cafeterias and other structures on the list make up one-fifth of the square-footage of California schools.

Corbett's legislation, AB300, noted that several other categories of structures have received seismic safety evaluations and pending or completed retrofits.

Hospitals, state prisons, state government buildings and community colleges, as well as California State University and University of California buildings, have been evaluated for their earthquake readiness, and many of them are now retrofitted or replaced, according to the California Seismic Safety Commission. Bridges and dams have also been evaluated and, in most cases, retrofitted or replaced.

"Our local schools are just as important," Corbett said.

The school building list, however, came with a twist that has likely limited its use: The legislation authorizing it prevented the public release of the names of schools on it. Districts had to request the list, according to a 2003 letter sent to every school district in the state.

Corbett said she didn't know why the legislation prohibited the public release of school names and that then-Gov. Gray Davis' office requested it. A legislative committee added the stipulation.

One thing is certain — the cost would have been great had all the schools needed seismic work at the same time. The inventory report estimated the price tag for retrofit and replacement would approach $4.7 billion. Six years later, that figure is likely closer to $9 billion, Bonowitz estimated.

The law also didn't establish any system for monitoring which districts have requested information from the list or have independently evaluated their buildings.

"I really can't tell you how many are not evaluated," said Nat Chauhan, Bay Area regional manager for the Division of the State Architect, which oversees public school construction under the Field Act. Private schools are exempt from Field Act standards and weren't included in the inventory.

"There's been fairly good efforts, from what I can tell, from the districts that are in the more seismically vulnerable zones," added Dennis Bellet, a structural engineer with the state architect's office who works closely with the AB300 list.

Two days after an interview with the two state structural engineers, a state spokesman said State Architect David Thorman will send a letter to every K-12 public school district in California. The letter, which should start arriving in districts' mailboxes this week, reminds them of the list's existence and asks districts to request the list or to send updated information on their buildings if they already have.

An informal survey of more than 20 school districts around the Bay Area revealed mixed awareness of the list. District officials in South San Francisco, Belmont and Pacifica were unaware of it. One district in San Ramon had received an inaccurate list from an outside company.

A Moraga district superintendent found that 10 of his buildings were on the AB300 list, but he was skeptical of the notion that a once-acceptable building code is now potentially dangerous. The buildings also looked fine, he said, so he decided not to seek a seismic evaluation.

Oakland Unified School District officials declined to discuss the status of seismic evaluations and retrofits of the district's 158 schools. More than 15 schools in the district have one or more buildings on the list.

Several district officials described the challenge posed by requesting information that might suddenly saddle them with a compelling need for a construction project that could run into the millions.

But for Nellie Hungerford, an assistant superintendent with the Belmont-Redwood Shores Elementary School District on the Peninsula, the choice was simple once the list was brought to her attention.

"The first thing I'll do is contact a structural engineer to arrange a seismic evaluation," Hungerford said. "But once you do it and they say you've got a problem, that creates a new problem.

"But it's not something I plan to bury in the back cupboard now that I know of it. We make every effort to keep our children safe."

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