WAITING FOR THE QUAKE : At Risk: Public Buildings and Dwellings : Ordinances in L.A. County Fail to Cover Seismic Upgrading of Homes : Safety: Older, unreinforced buildings have been at the center attention. But experts say unreinforced masonry is not the only type of building to worry about.

Ralph Grippo, the Torrance director of building and safety, went to the Bay Area after the Oct. 17 earthquake and inspected 20 homes in Santa Cruz County.

Working as an emergency inspector, Grippo tagged more than half as unsafe to occupy, because “they had just kicked off the foundations.”

He came home worried about older wood frame houses in downtown Torrance.

But there is no law in Torrance, or elsewhere in Los Angeles County, that requires seismic upgrading or even seismic evaluations of single-family homes.

At least 22 cities in the county, such as Torrance and the city of Los Angeles, have earthquake safety ordinances. But they address pre-1934 unreinforced masonry buildings, which are often brick-faced structures concentrated in older communities, such as downtown Los Angeles and Hollywood.

Unreinforced buildings have gotten the lion’s share of public attention. But officials such as Grippo and other safety experts say unreinforced masonry is not the only type of building to worry about.

Single-family homes, old or not, that are not properly bolted to their foundations are at risk, they say. Other structures described as potentially hazardous are: buildings with first-story garages or carports, a style not uncommon in apartment and office buildings; buildings made of pre-cast concrete, commonly found in warehouses or industrial parks; concrete buildings constructed in the 1960s and earlier that could pancake the same way the Nimitz Freeway did in Oakland.

“We still have many hazards remaining,” said Fred Turner, structural engineer with the State Seismic Safety Commission in Sacramento. “Professional engineers have known this for years. Now the public is beginning to realize it.”

Parts of many heavily used public buildings are constructed with unreinforced masonry and remain to be upgraded, including city halls in Los Angeles, Pasadena, Culver City and Claremont, the Los Angeles County Hall of Justice and the County Museum of Natural History.

According to a state Department of Conservation estimate, 34% of the hospital beds in Los Angeles and Orange counties will be lost in the event of a major earthquake on the Newport Inglewood Fault Zone. State laws do not require hospitals built before 1972 to be seismically upgraded unless they undergo voluntary renovations.

There is an unknown number of buildings constructed after the Long Beach earthquake in 1933--which led to the first state and local laws requiring seismic resistance designs--that may not be safe by today’s standards. No inventory has been taken of them.

“There’s a large inventory of buildings which were built under codes in the 1930s or 1940s that were less strong than current ones,” said Pat Campbell, president of the Structural Engineers Assn. of California. “Those buildings may have structural problems in a major quake.”

The Uniform Building Code, a set of structural requirements for building construction and safety, did not require until 1952 that single family homes be bolted to their foundations.

There are no retroactive state laws requiring homes built before then to have such bolting done, officials say. Assemblyman Dominic L. Cortese (D-San Jose) introduced a bill two years ago requiring this, but it died in the face of realtor opposition, according to a spokeswoman at his office.

Other than unreinforced masonry structures, the only buildings covered by retroactive laws are public schools. The state, not local governments, has regulated school safety requirements since the Field Act was adopted after the 1933 quake. Even though that only covered new construction, a later law called the Garrison Act required that any unreinforced masonry schools had to be upgraded or abandoned.

Hospital construction standards are also controlled by the state under the Hospital Act of 1972. But it did not have retroactive provisions, and a survey done by the Office of Statewide Health Planning and Development showed that “80% of the buildings don’t meet the standards,” spokesman Derek Pogson said.

But David Langness, vice president of the Hospital Council of Southern California, said he believes most of the 164 general acute care hospitals in Los Angeles County meet seismic safety standards.

The safety of a single-family house might simply depend on the quality of construction, said Michael Krakower, a South Pasadena structural engineer. Most houses built before the 1950s were either not anchored or inadequately anchored, with bolts set too far apart. “Those kinds of things were not common unless you had a knowledgeable or creative builder,” Krakower said.

The danger of an unbolted foundation would be particularly acute in areas with loose soil conditions, Krakower said, such as the San Gabriel foothills or the hills above Monterey Park. In Torrance, the older homes downtown are built on piers instead of a concrete foundation, a condition building chief Grippo had found common among homes destroyed in Santa Cruz. No surveys have been done to determine the total number of homes built on piers in Los Angeles County.

The fact that none of the estimated 400 high-rises in San Francisco suffered major damage lends credence to the claims of local structural engineers such as Trailer Martin, president of the company that designed the 42-story One California Plaza and 53-story Citicorp 777 Tower buildings in downtown Los Angeles, that “big buildings are very, very safe.”

One reason is that they are less likely to resonate in step with the ground motions of an earthquake, due to their height, while a smaller building will shake more violently.

Another is that they are more “elastic,” said P. V. Banavalkar, the Texas-based engineer who did the structural designs for the tallest building in Los Angeles, the 73-story First Interstate World Center under construction in downtown Los Angeles. “When the seismic event stops and the building stops oscillating, it will come back to its original position,” he said.

That will not happen with many older and smaller buildings. The garage-fronted apartment houses in the Marina District of San Francisco that collapsed into the street are an example, as was Olive View Hospital, severely damaged during the 1971 Sylmar earthquake.

In these designs, the upper floors were stiffer and more resistant than the ground floor, so that during an earthquake, they moved differently. “It’s too much of a change,” said Carl Deppe, chief of the earthquake safety division for the city of Los Angeles. “The forces become excessive in the first story elements and you get failures or even collapse.”

After 1971, Los Angeles building code requirements were changed to soften the effect of that condition, Deppe noted, and new code changes going into effect in January are even more stringent. But Deppe added: “It’s still not a good condition to get a sudden change in stiffness from the upper stories to the bottom.” And the new requirements are not retroactive to existing buildings.

Another older type of construction that many now say is unable to absorb earthquake energy well is concrete frame design built before 1971. The Nimitz Freeway collapse Oct. 17, attributed to the failure of the joints and ties between its upper and lower sections, is an example of the same principle. This kind of concrete construction, Turner said, “exists in not only bridges but buildings.”

These structures have not been surveyed in Los Angeles, Deppe said, “most are commercial but there could be apartment houses and hotels. I expect in the ‘90s we’ll be going after this type of building.”