Many Call for Tougher Codes, Retrofitting

Like aftershocks rattling the region, the death and destruction from the Northridge earthquake is triggering calls for tougher building codes and expanded efforts to strengthen structures across Los Angeles and other quake-prone parts of California.

As with every major California earthquake in the last 60 years, the toll of last Monday’s 6.6-magnitude temblor in lives and property damage has thrust the issue of seismic safety to the forefront of public attention.

Earthquake safety experts warn that as devastating as the quake was, leaving 51 dead and more than 2,300 buildings uninhabitable, the losses could have been far worse.

“We have been so lucky,” said Samuel Aroni, former dean of UCLA’s School of Architecture and Urban Planning. “What would have happened if this earthquake had occurred at 4 in the afternoon instead of 4 in the morning? Thousands of people would have been killed.”

Aroni said only by learning the lessons from this quake and engaging in a concerted effort to prevent the collapse of buildings and freeways can the loss of life and property be reduced the next time the earth moves violently. “We can’t rely on luck,” he said.

Building officials, engineers and geologists said in interviews that a major part of that effort must involve the tightening of building codes and the strengthening of structures--from smaller brick buildings to apartment complexes and commercial structures to parking garages, and City Hall.

As squadrons of building inspectors examined thousands of structures that suffered the quake’s wrath, a preliminary picture began to emerge about the types of buildings that did well and those that fared poorly.

“The newer buildings in the city did not suffer the damage the older ones did,” said Bob Steinbach, emergency management coordinator for the Los Angeles Department of Building and Safety. A Times computer analysis found that two-thirds of the buildings declared unsafe were built before codes were strengthened after the 1971 Sylmar quake.

Building officials credited those code revisions with improving the seismic safety of newer buildings.

In the weeks, months and years to come, the question of why some buildings survived and others failed will be the subject of much investigation and discussion at City Hall and in the state Capitol. City Council hearings are planned in the coming weeks, after building officials complete their assessments.

Once the task of inspecting damaged buildings is complete, Steinbach said engineers will do a structural analysis of every building that was declared unsafe “to see why it didn’t perform the way it was designed.”

Already there are calls from several council members for stricter building codes for new structures and new requirements for retrofitting older buildings to save lives and reduce property damage.

Councilman Hal Bernson, who led the fight to require buttressing of unreinforced brick buildings that are considered the most hazardous, said the time to act is now, before the danger posed by earthquakes recedes from the public’s mind.

“After a tragedy like this, there is going to be an opportunity,” Bernson said. “It is only after something like this that you can get legislation that’s tough.”

Every major earthquake has its hallmark of tragedy.

The images of the collapsed Veterans Administration hospital in Sylmar and buckled freeway overpasses in the San Fernando Valley linger as the legacy of the 1971 quake.

The television pictures of the twisted and crumbled Nimitz Freeway resting on top of commuters’ cars and the broken upper deck of the San Francisco-Oakland Bay Bridge are vivid reminders of the devastation unleashed by the 1989 Loma Prieta quake.

Since the 1933 Long Beach quake that killed 115 people and led to the first seismic safety standards, every major earthquake has generated its own response.

After 49 people died in the collapse of a Sylmar hospital, legislation was passed to require stricter earthquake standards for new hospitals. The state also took the first steps to begin retrofitting freeway bridges to resist collapse.

When 43 people lost their lives on the Nimitz and Bay Bridge, strengthening freeway overpasses, bridges and interchanges took on sudden urgency--an effort that continues today.

With last week’s quake, the starkest scenes may be of crippled freeways and the collapsed apartment building in Northridge where 16 died in the worst concentration of death.

There are other haunting images of destruction--crumbled brick buildings, pancaked parking structures, a mangled mall and concrete offices reduced to rubble.

It is these failures that will be scrutinized most closely to determine what directions new and revised codes should take and where retrofitting efforts should be concentrated.

Although California has the strictest seismic safety codes in the nation, the magnitude of the damage stunned building officials.

“To those at the epicenter, this was the Big One,” said Gerald Takaki, chief of the Los Angeles Building and Safety Department’s Bureau of Community Safety.

Building officials must learn what happened to the three-story Northridge apartment building that suffered severe damage when one floor collapsed onto another, Takaki said. “We’re going to have to look at that very closely.”

City and state officials said the wood-frame Northridge Meadows apartment building did not appear to have plywood reinforcement in the stucco walls, a seismic safety feature that was not required at the time of construction in the early 1970s, but is now. The builder said he believes that plywood was used.

In 1973, two years after the Sylmar quake, the building code for new apartment buildings was tightened to require plywood in the exterior walls to help resist the lateral movement of an earthquake.

The code was not retroactive. But the Northridge apartment’s collapse prompted former state geologist James Slosson to say: “Now we have to do it for apartment houses built from 1950 to 1972.”

After seeing the building, Tom Tobin, executive director of the California Seismic Safety Commission, urged local officials to require reinforcement and strengthening of older low-rise apartment buildings, especially those built over parking garages. “They clearly have a very characteristic weakness,” he said.

Bernson, whose heavily damaged San Fernando Valley council district includes the quake’s epicenter, vowed to press for passage of an ordinance that would require retrofitting the type of apartment complex that failed. “They have proved to be one of the most dangerous types of buildings that we have,” he said.

Building officials also are concerned about the failure of a number of so-called tilt-up buildings, commonly one-story or two-story warehouses or commercial buildings, where the concrete walls are lifted into place and anchored to a wooden roof. In a serious earthquake, the walls can tear away, collapsing the roof.

Karl Deppe, former chief of the city’s Earthquake Safety Division, said the collapse of tilt-up buildings in the 1987 Whittier Narrows quake caused the building department to draft a retrofit ordinance for that type of construction. The proposal was ready more than a year ago, Deppe said, but did not go to the City Council because of concerns about its impact on businesses during a deep recession.

Tobin said the estimated 100,000 tilt-up buildings across the state are “the backbone of California commerce” and should be safeguarded. Retrofitting is relatively simple, he said, and can be done at a reasonable cost by installing steel straps to link the roof to the concrete walls.

Much more difficult and costly is strengthening older concrete frame buildings that are not flexible enough to withstand powerful shaking in a major quake. Building officials said one of these structures, the Kaiser Permanente building in Granada Hills, suffered severe damage when the concrete in supporting columns shattered.

The same problem, officials said, forced demolition of a severely damaged high-rise medical office building at Olympic Boulevard and Barrington Avenue on the Westside.

Bernson said he wants building officials to consider requiring the retrofitting of this kind of “non-ductile” concrete building, which sometimes are too rigid to withstand the bending of earthquake forces.

Requiring retrofitting of buildings is not an easy task for government.

If history is any guide, property owners are likely to resist efforts to force them to upgrade existing buildings.

It took until 1981--10 years after the Sylmar earthquake--for the city to adopt an ordinance requiring owners of unreinforced masonry buildings of more than four units to strengthen them so the walls that support the building do not collapse.

Since then, Deppe said 95% of the city’s 8,100 unreinforced masonry buildings built before 1933 have been retrofitted or demolished.

Although Monday’s quake caused extensive damage, Deppe credited the retrofit program for the fact that no one died in the older brick buildings.

City Councilwoman Jackie Goldberg, whose Hollywood district was hard hit in the quake, said she wants officials to study whether the retrofit requirement for unreinforced masonry buildings should be expanded to brick buildings with fewer units.

Building officials also would like to extend the retrofit program to include other steel and concrete frame buildings that have unreinforced masonry in the walls. Deppe said City Hall is the tallest building of this type in the city.

Although not embracing any specific changes, City Council President John Ferraro introduced a motion Friday calling on building officials and the Fire Department to review the building code and make recommendations for “any earthquake reinforcements to damaged structures that may be needed to avoid collapse of those structures” in the future.

“It takes an earthquake to get people’s attention,” said Bill Petak, executive director of USC’s Institute of Safety and Systems Management. “Society tends to be pretty reactionary. It’s the horse-out-of-the-barn syndrome.”

A member of a recently formed city commission on seismic safety, Petak said there is a need to move ahead with an expanded retrofitting program for existing buildings. “New buildings are not the problem,” he said. “It’s the old buildings.”

The difficulty boils down to economics--a struggle between the need for seismic safety and property owners who would be forced to pay the cost.

“Trying to get ordinances and legislation passed that cause building owners to spend sums of money to retrofit these buildings has always been a problem,” said Rawn Nelson, president-elect of the Structural Engineers Assn. of California.

“It took 10 years to get through L.A. city an acceptable ordinance for retrofitting of the unreinforced brick buildings. It took longer for the state to adopt it, and for the local municipalities to then follow through and enforce it,” Nelson said.

To ease the burden on building owners, the Seismic Safety Commission’s Tobin believes that some kind of tax credit or tax incentives are needed for those who invest in earthquake safety.

Slosson, the former state geologist, said “the basic philosophy . . . is as you learn, you improve design and construction. There is a gradual improvement.”

But it is far more difficult to win approval for measures that require changes in existing buildings. “Unless (there is) a very serious crisis, you never make the code retroactive,” he said.

Attention needs to be paid to retrofitting hospitals that were built before the Sylmar quake and have not been upgraded, Slosson said. The law passed after the Veterans Administration hospital collapsed applied only to new hospitals, not existing ones.

The Van Nuys-based geologist also urged officials to examine the design of parking structures where hundreds of people can be found at peak periods during the day.

Parking structures at the Northridge Fashion Center and Cal State Northridge campus collapsed or suffered severe damage.

“The code obviously is not stringent enough on precast (concrete) parking structures,” said Bob Harder, manager of the Building and Safety Department’s Van Nuys office. “We need to look at that again.”

In addition, Harder said, building officials need to look at construction of single-family homes which, according to a Times analysis, accounted for 18% of the buildings declared uninhabitable so far. Many homes sustained major damage, he noted, even though they were bolted to their foundations.

Local, state and federal governments have much work to do to improve the seismic safety of their own facilities, said Tobin of the Seismic Safety Commission.

“I think government should be ashamed of its progress. There is no question that government is far behind,” he said. “Earthquakes are something that will happen. We all have a responsibility to deal with them.”

Proposed Changes

In the aftermath of the Northridge earthquake, several Los Angeles City Council members are calling for stricter building codes and expanded programs to improve the seismic safety of structures that suffered heavy damage.

Unreinforced masonry buildings: City building officials say a retrofit program to prevent collapse of older brick buildings saved lives. One proposal would expand the effort to residential buildings with four units or less.

Apartments: Attention is focused on the design and construction of low-rise apartment buildings.

Parking structures: Building officials want to investigate why modern parking structures failed in the quake.

Concrete office buildings: The Kaiser Permanente clinic and office building in Granada Hills that failed in the quake is an example of an older concrete building that lacks the flexibility to ride out severe shaking.