Kobe disaster shakes up earthquake codes.

In 20 seconds Kobe shook apart. Scientists say it could happen here with even more devastating results. New York City has ten million people in town during the day and 7.5 million overnight - Kobe has a population of 1.4 million. Half of New York City's buildings are constructed of unreinforced concrete, while soil in many places would liquify in a trembler.

Because the Kobe quake, measured at 7.2 on the Richter scale, was shallow in the ground, there were many splits in the earth and the shaking was intensified. Its older homes crumbled, water mains cracked and fires broke out, despite regulations that gas mains be automatically shut off in a quake. Newer buildings, however, constructed to more stringent earthquake-resistant codes, appear to have survived with less damage. Its Port Island, constructed of landfill, was shaken up, putting world cargo facilities out of business.

While New York City has had two earthquakes of approximately a magnitude of 5, the last one of 5.5 was in 1884. The quake 150 years before that was approximately a magnitude 5. Scientists feel it is only a matter of time.

Since the 1980s, visionaries in the seismic, real estate and construction community, organized by former New York City Building Commissioner Charles Smith, have been working to revise city building codes with an eye on life safety issues.

They were inspired by the San Francisco quake of 1987 and were working on the codes during the 6.6 magnitude Northridge, California quake last year. They put the finishing touches on the documents on January 13th, when it passed the City Council's Committee on Housing and Buildings unanimously. Hours later, citizens of Kobe, Japan had their lives irrevocably changed as a shallow earthquake jolted the city awake. The city code is expected to be adopted by the ftill Council on Feb. 2nd.

Dr. Klaus Jacob, senior scientist at the Lamont Doherty Earth Observatory of Columbia University at Palisades, said the New York City codes are designed to protect people for an earthquake of a magnitude expected to take place once every 500 years. The code should help save lives during a quake of a magnitude 5 within 20 miles.

"It would be good for a 6 at a 30 to 40 mile range and a 7 out to 80 or 100 miles," he said. "But if and when we had a magnitude 6 or 7 under the city - which is a low probability but is a possibility - it would not be good enough. It would not prevent the preserve life safety. It is not to prevent building damage and financial loss."

Early on, the Codes Committee members decided to take the 1988 Uniform Building Code - known as the California Code - as a model and then revise it for use in New York City. The California Code adds a cost of about 20 percent to construction and tends to try to save structures as well as lives. It also does not take into account the most current research, particularly on soil conditions as they affect the buildings above.

Deborah Beck, executive vice president of the Real Estate Board, was a "formidable" member of the committee, say the other engineers, scientists and government participants, and helped to shape the discussions to take into account the costs of the structural changes.

Beck anticipates the incremental costs, ranging from 2 percent to between 6 percent and 8 percent of the total building construction costs, will be mitigated because of the "creativity of the design community" in the city.

"While it will cost more, it will not cost more than it has to have such a code," she insisted, "and the public is well served here, in that it will add an incremental element of life safety if there is ever an earthquake with its epicenter of New York City,"

Guy Nordenson, principal of Ove Arup & Partners and chairman of the city's code committee, notes that since New York City is considered a Zone 2, with Zone 4 as the highest risk, "You can't start with the same philosophy as in California. We were after protection of life and tried to trim out anything from the code for property."

Jacob says the seismologists and engineers would have liked to have a more stringent code. "The real estate industry voiced its concerns and we had to find a level," he noted. "We are not below the national level, and in some instances considerably improved without increasing the costs."

A big issue was separation between buildings. "In California they needed 1.5 feet between two buildings, "explained Nordenson. "We decided to deal with that in a more judicious fashion because above a certain height the [buildings] are set back."

Under certain soil condition, costs will be higher. Marshland, sand and landfill can liquify during an earthquake, so "there are much more expensive requirements for the foundation and the ways it is supported, as well as the interconnects," said Beck.

Research conducted after the Mexican earthquake and the recent California quakes determined the amount of movement and the severity of movement are significantly different, up to a factor of six depending on the soil conditions. "If you are on hard ground in San Francisco you are probably safer than on soft soil in New York," warned Nordenson.

Areas built on landfill in Kobe were severely affected, as on the Port Island, where much of the city's international shipping and cargo transfer takes place.

Jacob said the soft soil can be carted away, while in other areas people will have to drive pilings. Others they will need to make the piling stronger by pumping concrete in, known as grouting, or the soil can be densified by vibrating. "The best thing, of course, is not to build on such stuff," he said.

As the New York City codes were being revised, committee members were also working with National and State committees, rewriting those seismic codes. Much of the research on soil liquification that will be adopted in the city will also become a part of the other standards.

According to Joseph Kelly, P.E., senior consulting engineer with the Port Authority, who chaired the State Seismic Code committee and, was a member of the city group, that code is currently having an assessment analysis completed before public hearings start.

"The committee effort was try to look at the model codes and put it in what would be more germane for New York State," he explained. The state has seismic activity of varying intensity, with the most intense regions in the North in St. Lawrence, Franklin, Clinton and Essex Counties.

"There is a concern in the New York City area for bridges tunnels and subways, and also a concern for disaster relief planning, which the city agencies are grappling with," added Kelly.

According to a report issued last month by the Inland Marine Underwriters Association (IMUA) on regional variations in seismic risk outside of California, a sizable quake striking New York City during business hours could leave 280,000 dead and billions of dollars in property damage, causing fires and a possible tidal wave.

James Mooney, the IMUA president, notes there are several faults around New York City and New Jersey. "You have a honey in the Palisades on the Jersey side of the bridge," he says, refening to the Ramapo fault. There are at least three faults in Manhattan and others in the outer boroughs.

"Insurance agents should be informing you if you are in flood prone areas," said Mooney. "But I can understand why agents in this area aren't the first to say, `Do you want an earthquake policy?' These are neglected perils."

The New York City and New York State codes also do not take into account retrofitting of existing structures unless the building is increased in size.

The IMUA report estimates the cost of retrofitting all of the nation's seismically unsafe buildings by the 2020 to be $60 trillion.

The real issue is how do you treat all the other buildings retroactively," asked Richard Thomasetti, P.E., a principal of Thornton-Thomasetti Engineers who was a member of the city committee. "That's a major undertaking and major event." Thomasetti said there will have to be a lot of thought as to which buildings would see seismic damage and the use of that building.

"If it's a garage that is going to fall over, you are going to treat that differently than a masonry hospital wing. Schools would be another priority," he noted. "These are very real problems."

Along with retrofitting fire and police stations and hospitals, Klaus believes the city should consider retrofitting a national treasure or a building that has an important financial or historical function, such as the New York Stock Exchange. The City Halls in Salt Lake City, Utah and San Francisco are being retrofitted, as well as other buildings. "It's not an inexpensivejob, but you can't do it on a New York City kind of a budget," be warned.

"I am truly worried about the financial services industry being hard hit," Jacob said. "They could lose a lot of their data facilities."

He doesn't believe back-ups as close as New Jersey are appropriate and suggests sending data and having facilities separated as far as Boston or Washington, D.C. from New York.

Federal mandates currently require buildings owned or occupied by Federal agencies to be retrofitted to account for seismicity. Just to seismically retrofit the federal government's three billion square over feet of owned and leased office spake over the next 35 years will cost up to $1 billion annually, the IMUA report says.

Kelly said they are looking into retrofitting the U.S. Customs Building at 6 World Trade Center, which is rented by Federal agencies. The Twin Towers themselves were designed to withstand a direct hit by a Boeing 707 and have already shown they can withstand a bomb blast at the base.

The new Federal Courthouses, as well as the new Federal office buildings, have been built to resist earthquake forces, as has the New York Hospital addition cuffently under construction over the FDR Drive, designed by Thornton-Thomasetti Engineers.

Thornton-Thomasetti Engineers have also been designing cargo facilities for the Port Authority at JFK Airport to meet the new city code, which will not take effect for a year after being signed into law by the Mayor.

The time lag is to give designers, developers and lenders time to incorporate the increased costs into project costs and loans. "Anyone who wants to do something on a voluntary basis to enhance the marketability or enhance a technical feature can do go as long as it is approved for use in the City of New York," advised Beck.

Agrees Jacob, "If the body political and the owners decide to build safer, they are encouraged to do so. These are minimum requirements, not maximum."

Most of the buildings at risk in New York City are not the skyscrapers, which are built stronger and for high wind loads in good Manhattan bedrock, but the unreinforced masonry lower rise structures, industrial buildings and tenements.

Thomasetti said unreinforceed masonry buildings are usually in the eight to ten story category. "But still, with a concrete building 15 to 20 stories high, they have a lot of ma&s not designed for much wind, and seismic forces would be greater," he said.

The new city codes will no longer allow unreinforced structures to be built over three stories tall, although the Building Commissioner will have the power to impose the code on shorter buildings.

According to Housing and Building Codes Committee counsel Anthony Baronci, "There has to be certain resistance these buildings will have to withstand in an earthquake and that will have to be taken into consideration when designing."

The law will affect new buildings as well as those buildings where enlargements increase the footprint, on either new or existing foundations, or where enlargement exceeds 60 percent of the value of the building.

Equipment above head level, such as piping, HVAC equipment and ceilings, will have to be able to resist certain horizontal forces. Structural steel will be treated differently, along with the unreinforced masonry.

The reinforcing is like the inner laminate on safety glass," explained Nordenson, and it will help to, hold the masonry together.

That's good news for Mooney and the insurance industry. "That stuff is like a potato chip in an earthquake," he explained.

Another important part of the new code will be new conditions for attaching glass curtain walls to the buildings. It will improve the integrity of the curtain overall, then the connection of the panels will be improved and won't come off as easily, said Nordenson. "But the integrity of the glass itself is not really affected. That would have created a revolution. It was nice to see over time that people realized it was important.'

The curtain walls are still constructed with amealed glass, womes Nordenson. "It's not tempered and it breaks into big pieces and they are going to hurt people. You probably want it to be laminated, but it's a difficult problem because any way you can think of solving the problem, another problem comes up."

Recent research has shown some of New York City's cuffent practices are somewhat safe. "We bolt our connections and there is less susceptibility [to pancaking] than in California because there is more redundancy," Nordenson explained. "West Coast engineers used to sneer at our steel practices."