Lessons from the Canterbury quakes

20:56, Jun 02 2012
italy
FAMILIAR PLIGHT: Left: workers at the damaged Cathedral of the Blessed Sacrament in Christchurch, and, right: firefighters working at a damaged church in Crevalcore near Modena, Italy.

The eyes of the engineering world are on Christchurch as lessons from the dramatic earthquakes are learned and used in the creation of new, more resilient and safer buildings. PHILIP MATTHEWS reports.

Bad news refuses to stand still and in the past 15 months, Christchurch's earthquakes have been superseded by others.

On Tuesday evening New Zealand time, a 5.8 magnitude earthquake struck northern Italy, around the Emilia- Romagna region and the ancient city of Modena. By yesterday, the death toll was 17.

In a tragic irony, the Christchurch president of the New Zealand Society for Earthquake Engineering (NZSEE), Stefano Pampanin, comes from that part of Italy. For a moment, he had to shift his attention from Christchurch's post-quake building issues back to his home.

None of his family were directly affected.

"The town most of the family comes from, Bobbio, is in the same region and our house is three-storey unreinforced masonry, but with big and thick walls," he says. "My parents were there during the weekend and got shaken but it's far away enough from Modena - more than 100km. But even Milan was shaken and people got out of schools and offices. It's very sad, to be honest."

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Growing up, Pampanin remembers it was a low to moderately active seismic area. In Pavia, where he was born and raised, there were small earthquakes from time to time - long-distance ones. He felt a few earthquakes in California in the late 1990s, when he was in San Diego, but until Christchurch, Pampanin's main earthquake experience was in L'Aquila, central Italy, when a 5.8 magnitude quake hit in 2009, killing 308 people.

Pampanin spent a couple of months working in L'Aquila in the aftermath.

An associate professor in structural design and earthquake engineering at Canterbury University, Pampanin has been president of NZSEE since April; he was elected at the society's annual conference in Christchurch. In the same month, his research into residual capacity and options for repairing reinforced concrete buildings was funded to the tune of $450,000 by the Natural Hazards Research Platform.

Why was he picked as NZSEE president? Partly it is the legacy of earthquake work at Canterbury University and, he suspects, partly his nationality.

"I have the possibility or capacity to be not only aware of the wider aspects of earthquake engineering, but to also be able to engage, lead and drive people and probably because of my Italian nature, I tend to be quite direct," he says. "I tend to say things that I need to say and that is somehow appreciated and seen as useful when delicate decisions are to be made.

"There is an opportunity and responsibility to work together for a common goal instead of having different entities that are quite disconnected, which was a perception, partially true, that many people had."

The NZSEE was formed in 1968 to foster the science and practice of earthquake engineering and promote co- operation among scientists, engineers and other professionals. Now more than ever, it needs to speak with one voice, and make the most of its internal connections.

"The world has been looking at New Zealand in terms of an earthquake engineering legacy for decades, because we have a very good tradition here.

"It comes from the University of Canterbury and New Zealand as a country since the 1960s. The legacy has allowed the city to not be completely flattened by the earthquakes. The shaking intensity of the February, 2011 event was much bigger, as we know now, than buildings were designed for. New Zealand is a model and people are still referring to what is going to happen as a potential model."

Just as the outside world helped in the immediate recovery, it continues to help, in lower-profile ways.

"We are working with many other universities and scientists at an international level to get the best out of the lessons learned."

In August, Pampanin will be in San Francisco, meeting with representatives from respective earthquake engineering societies from Japan, the United States and Europe.

"That will be specifically to address lessons learned from Christchurch, which are lessons for the whole world - what we can do in terms of the development of new design codes, implementation of new technologies for both the design of new buildings, structures and infrastructures, as well as the retrofit and upgrading of existing ones, the whole spectrum."

A month later he will give the keynote address at the world conference in earthquake engineering. Held every four years, it usually attracts around 3000 practitioners; this year, it's in Lisbon. His keynote speech will be on new trends in earthquake engineering, design and implementation of low-damage technology.

People are "hoping and waiting for New Zealand to come up with something unique, a breakthrough in earthquake engineering applied to the real world and Christchurch can be the first model for such a revolution - a city that is going to be not only beautiful but much safer."

But locally, the feelings of residents about the city's architecture since last February have probably slumped. In general terms, we have gone from thinking that much of the city came through surprisingly well to being alarmed at how much is coming down. Is this fair?

"It's a very delicate situation," Pampanin says. "There is a quite clear and common understanding and agreement between engineers and scientists, not only nationally but internationally, that the intensity of the ground shaking experienced in the central business district was so much bigger than the design level that it was actually a positive surprise that the city came out as it did in terms of buildings not collapsing in the numbers that statistically would have been expected to occur.

"The expectation would have been a much higher number of buildings collapsing and a much higher number of fatalities.

"It is hard to think in this way, but there is partial good news. The design codes have been continuously and rigorously refined and improved over recent decades, as more knowledge has been developed, and in general terms properly implemented, but the reality - a reality that engineers and scientists did know but the population did not - is that the buildings were mainly meant to protect the lives of people and this was in an under-design-level earthquake, which February 22 exceeded.

"From this point of view, the performance of the buildings was generally very good, if not better than what was expected, but the expectations are different from a technical point of view than from the general population's point of view.

"The new revolution in earthquake engineering that is going to happen is to deliver a building, a city and a country that is up to the expectation of the people. The expectation of the people is not that a building will have to be demolished after an earthquake."

He likes the analogy of a car in a crash: you survive but the car is destroyed. That was the thinking. The next step is to ensure that buildings survive, which is what the general public now expects.

"The good news is that what we are capable of doing in 2012 is much, much better than what was possible in the 1970s and 1980s."

A new building for the College of Creative Arts at Massey University in Wellington was built using post-tensioned materials in techniques that Pampanin helped to pioneer at Canterbury, with Andy Buchanan and Alessandro Palermo. Essentially, the building will sway and then spring back to its original position.

"Things are going to change rapidly," Pampanin says. "It's just that, until recently, there was no appetite for people to change. There was a negative prejudice that new things would cost more, but we know that it doesn't happen that way for other technologies. New televisions, new computers and new cars do not cost more in relative terms and they clearly perform better than old ones."

Christchurch will be or can be safer with strengthening on existing buildings also. "People naturally say, who is going to pay? Without putting that question, it must happen."

He says there are models around the world in which government incentives, private money and insurance combine to pay for it. Reduced premiums and tax rebates are ways of incentivising the retrofit of vulnerable buildings as well as the design of new ones based on low- damage technologies.

Hence, earthquake- resistant cities are much more possible than people might think.

"We say it is unacceptable to not implement in 2012 what we have in our hands already."

The key is that, post- earthquake, better-informed tenants are asking for the proper option, not the cheapest option.

"Asking today for 1970s-80s technology is the cheapest option."

In the wake of the quakes and the worldwide attention, you would expect to see a new level of interest in earthquake engineering at Canterbury University.

Actually, it is more about understanding than interest, but Pampanin says there is also increased demand from people overseas wanting to come to Christchurch, as "this is becoming an open-air laboratory".

In work ranging from building damage inspection to computer modelling of how buildings performed under the shaking and what they could do if retrofitted or designed according to new technology, "this is at the moment the best place to see all of it".

As far as student demand is concerned, Pampanin says there is more interest from practising engineers who want to be brought up to date on the latest designing, strengthening and retrofitting methods.

There is also an emphasis on making information accessible beyond the specialists.

"Communication has always been a problem in any research-oriented field. When we go to a specialist, technical conference we tend to preach to the converted, but in April we had a very successful and unique conference in Christchurch with 400 people.

"We pushed for that conference to be open, outside the standard area of expertise covered in the past, like engineering seismology and geology, structural and geotechnical engineering, so it was not just for people working in the field but people affected by and managing the response.

"Everyone from the community level to national government level, with local authorities, insurers and contractors, were informed and shared discussion. There is an urgency, of course. People are no longer asking when it's going to happen and how, but what we can do about it."

His homeland is a reminder of that.

"In Italy, every few years we get hammered by severe earthquakes and the lessons are unfortunately always the same. Unreinforced masonry buildings collapse if they're not retrofitted, minor actions can significantly reduce the seismic risk and overall catastrophic impact, but these actions need to start some time and from somewhere."

In Italy, people are keen to preserve heritage buildings as much as possible. There are anecdotal records of earthquakes going back to the Romans and the historian Pliny. The quake in Modena this week appears to have been the biggest since 1100 to 1300; some of the monumental buildings destroyed were built in the 14th century, which shows how many quakes they withstood and the relative size of the latest one.

In Christchurch, the historical record has been much shorter, which is another reason why the recent sequence was so unexpected.

"It means that we could expect something bigger than building code prescriptions almost anywhere. On the one hand, this is scary. On the other, it means there should be a plan for strengthening and upgrading buildings continually."

Speaking personally, as a citizen and father of two young children, he says he would like to see a budget in place for this with an associated multi-year plan for implementation.

"A design code is only one kind of progression. The most important is the take-up from the market, people and industry and policy to facilitate the implementation."

Does he have a position on whether the Christ Church Cathedral should be rebuilt? The NZSEE has a position on the importance of all heritage buildings and the need for engineers to consider the societal expectation to preserve heritage value without compromising safety. A statement came out of the conference referring to - but not limited to - the Christ Church Cathedral "saying clearly that a proper technical debate should be considered, that valuable technology is in general terms available to repair, upgrade and strengthen heritage buildings of that nature".

"Obviously, it doesn't come for free but because it can be done and the modern perception is that some iconic heritage buildings are not only privately owned buildings but somehow community buildings, the position of the society is that technical consideration of strengthening should be done and the cost should not have been, in that phase of the debate, a consideration."

Pampanin saw the recent poll in The Press that said that roughly half the population is opposed to a rebuild, that they see "the cathedral as either irreparable or unsafe to keep up, or a bad memory of what has happened".

"It's very emotional and that has to be respected. But man-made demolition of such an important building could have been delayed.

"For example, the Leaning Tower of Pisa was in trouble from the beginning of construction and never was meant to be restored straight but there have been one or two expert committees every century given the task of preserving that monument for the next generation. The cathedral, as a symbol of the history of the city, could have been preserved for the next generation so that people in a less emotional atmosphere could make the decision about what could be done and what could not. In the meantime, strengthening could have been done."

The NZSEE position on all heritage buildings is that, technically, something can be done so at least alternative options should be considered with care.

"My personal opinion is that the cost should not be on the shoulders of the private person when it is accepted that the buildings represent something more than the private interests."

 

The Press