Advice on How to Reduce Quake Damage Urged for Building Codes

The state’s building codes should include not just mandatory earthquake standards but also guidelines to advise property owners, designers and contractors what additional steps they may take voluntarily to reduce earthquake damage, a new report says.

In a 500-page report commissioned by the federal and state disaster agencies, the Structural Engineers Assn. of California said it is time to move beyond the mandatory minimums in the codes--which have done a good job of preventing building collapses and loss of life--into the more difficult areas of keeping buildings functional and preventing non-structural damage.

Returning offices and homes to normal operation has proved to be an unexpectedly costly element of recovery efforts.

Ronald F. Nelson of Costa Mesa, president of the Engineers Assn., said Wednesday that his group is under no illusion that such voluntary expenditures will become commonplace without tax incentives and a willingness by the insurance industry to give lower deductibles and premiums to those willing to follow the guidelines.

But, he said, recent quakes have shown it is not enough to make buildings structurally safe. Their contents must also be protected, and detailed prescriptions for how to do this ought to be placed in the codes.

“Right now, everyone is suffering from the recovery costs,” Nelson said. “Move the site of the Northridge quake to Downtown L.A., and you’d have another Kobe.” (Damage from the Jan. 17 earthquake in Kobe, Japan, has been estimated to exceed $100 billion, four or five times the total for Northridge.)

Chris Poland, the San Francisco engineer who chaired the committee that prepared the report, said its central point is to advocate expanding building codes to “look at the entire building.”

“In a newspaper office, for example, present codes do not require the architects to worry about the computers or the presses,” he said. “These guidelines would point out what to do if you are worried about protecting those elements.

“Any structural engineer can provide a higher level of performance where people want it,” Poland said.

“Here, we may in the future have charts showing how certain steps will reduce damage to such and such an extent, depending on the size of various earthquakes,” he said.

“Up to this time,” Poland added, “the focus has been on a single style of performance for every building. . . . Engineers were given direction that safety was the only concern. But in Northridge, while the structures did marvelously, the price tag after safety was so large that there has been an outcry for more complicated overall standards.”

The report follows months of debate in the state Seismic Safety Commission over setting a standard for what constitutes acceptable risk in California structures. There, too, the issue has been whether to adopt standards that would mandate continued functionality of buildings after severe shaking, rather than just ensuring against their collapse.

The majority opinion on the commission up to now has been that legislators would probably balk at making a functional standard mandatory because it would add so much to building costs.

The engineers, however, are taking the position that if guidelines are provided, some may decide voluntarily that the long-term savings exceed the short-term costs.

L. Thomas Tobin, executive director of the Seismic Safety Commission, said such an approach would have limitations. “The long-term investors might go along, but the speculators won’t,” he said.

“Still, reducing seismic risk has a value,” he said. “A building built to a certain standard would have a higher value, and once we’re able to recognize higher standards, property values will reflect them.”