Earthquake Prompts State Review of Safety Codes : Preparedness: California begins review that could bring major changes for agencies and property owners. Areas of concern include gas connections, water mains and dam construction standards.

Based on preliminary evaluations of highway bridge collapses, damage to dams and breaks in natural gas systems, the state of California is embarking on an unprecedented review of codes and regulations to determine if they provide adequate protection from earthquake forces.

Gov. Pete Wilson, acting on the advice of experts in the aftermath of the Jan. 17 Northridge earthquake, has directed the Seismic Safety Commission to investigate a number of matters with wide-ranging implications for property owners and public agencies.

Among the issues is whether gas pipe connections at buildings should be made of flexible material to help prevent rupturing during a quake.

Another is whether hillside construction should be subject to stricter seismic standards than those in the building codes.

Also to be studied is whether dams that are built between hillsides where quake forces tend to be magnified are more vulnerable to damage than previously believed.

The Northridge quake, state officials said, has provided a unique opportunity to study the impact of seismic activity beneath one of the world’s largest urban centers.

“(We want) to take advantage of an unfortunate incident to learn what lessons we could apply to another occurrence should that happen,” said Andrew Poat, Wilson’s chief deputy Cabinet secretary.

L. Thomas Tobin, the seismic commission’s executive director, said the agency will begin its work this week, organizing into four teams, each with responsibility for specific areas. The teams will examine the seismic safety of bridges, dams and water and gas networks, as well as building codes, land-use planning and geotechnical issues raised by the quake.

This review of the state’s most essential support systems, Tobin said, is unprecedented, although the commission did undertake a study of the recovery process after the 1989 Loma Prieta earthquake.

Wilson had issued a directive in February ordering the commission to examine building codes. With little public discussion, the governor later broadened it during a series of commission hearings in which seismic and geologic experts raised questions about the vulnerability to earthquake forces of dams and other structures.

A Caltech engineering professor warned that damage sustained by the Pacoima Dam in the San Gabriel Mountains during the Northridge quake may be an indication that dams are more vulnerable than thought. Others suggested that breaks in gas lines caused by unusual ground forces may have shown the need to re-examine the safety of natural gas systems.

Tobin said the commission has been given a Sept. 1 deadline to produce a report and recommendations. He said in the meantime he has applied for a $716,000 federal grant to cover the costs, including contracts with outside experts in seismology, geology and engineering.

“We want to learn what was unique about this earthquake and what implications does that have for the way we do business in California,” he said.

Assemblyman Richard Katz (D-Sylmar), whose legislative district encompasses the areas hardest hit by the quake, said it is essential to incorporate the “new science” that is spawned by each earthquake into codes and regulations governing structures and lifeline systems.

But he said he was concerned that the Sept. 1 deadline set by the governor would not give the Legislature time to act on any of the commission’s recommendations this year while memories of the quake’s devastation are fresh. As time passes, he said, it becomes increasingly difficult to win legislative approval for proposals that require additional expenditures or the enactment of new controls on building and development.

“If you’re serious about using the results of this study, you need it by Aug. 1. . . . Otherwise it becomes a report that sits on the shelf,” Katz said.

Poat and Tobin said Wilson would not have ordered the review unless he intended to act on it. “I think that there will be a commitment to follow through . . . at the highest level,” Tobin said.

Although the teams have yet to formally determine their path of inquiry, Tobin said the earlier hearings provide a general outline of issues. For example:

GAS AND WATER SYSTEMS

Peculiar ground motions in some locations in Los Angeles County caused gas lines to be stretched and pulled apart, fueling numerous fires. Likewise, water mains broke under the same stresses, leaving many areas without water for long periods.

The commission will look at codes to see if some gas lines and water mains ought to be rerouted away from certain soils that could be subject to a particular kind of ground motion during a quake.

They also will look more closely at what caused numerous residential fires that broke out. Should there be a change in the code governing gas connections to houses, perhaps directing that there should be flexible fittings instead of hard fittings? Should gas mains have cutoff valves activated automatically by certain vibrations, or should a control center shut down the lines after a quake?

Water distribution lines will be studied to see whether there should be a recommendation to replace older lines with newer pipes.

DAMS

During the Northridge quake, ground acceleration measured at the 365-foot-high Pacoima Dam reached a peak of twice the force of gravity. It created a two-inch gap at the abutment to the canyon wall. Although less severe, the damage was similar to what the structure sustained in the 1971 Sylmar quake.

Caltech engineering professor John Hall told the commission he believes the dam might have failed if the quake had struck on one of the rare occasions when its reservoir was full. State officials insisted that the dam, even if full, would have survived. The commission will try to determine if full reservoirs make dams more vulnerable in a quake, or if the weight of the water can make them more stable.

Although no dams in the Los Angeles region came close to failure, the commission will study whether the location of the dam in a high canyon may have contributed to the high ground acceleration. The results could have far-reaching implications for the safety of all dams in earthquake areas.

BUILDINGS

The minimum standards for most buildings are tied to life safety--that is, buildings must be strong enough that they will not collapse and kill someone.

But Tobin said that that performance standard is being challenged because some buildings that remained standing sustained so much damage that they could not be repaired.

He said the commission will ask: “Should we be accepting as much damage as we have had in buildings, and if we shouldn’t, how do we accomplish that and pay for it?”

The commission will examine the standards for houses and mobile homes to see if they will allow structures to withstand the kind of shaking--particularly the vertical motion--that occurred during the Northridge quake.

BRIDGES

While the California Department of Transportation is conducting its study of bridges, the commission wants to look at the design standards for elevated structures on the highway system.

Tobin said the question to be examined may be whether Caltrans gives enough consideration to localized geological formations when designing bridges. Soil conditions at the Golden State-Antelope Valley freeway interchange are believed to have played a role in the collapse of bridges there.

In each of its studies, Tobin cautioned that the commission will not be investigating to determine why individual structures failed. “That’s not our goal,” he said. “Our mandate really is to look at the adequacy of our approach to seismic structural safety and the adequacy of our codes.”