Chile’s Earthquake: An Architect’s Perspective

Sebastian Gray, Architect

Sebastian Gray, Architect

In the aftermath of one of the strongest earthquakes on record, the world has turned its eyes to Chile and has been amazed at how relatively little structural damage was done in comparison with lesser quakes in other parts of the world. I asked my friend Sebastian Gray, an architect and professor at the Universidad Católica de Chile, for answers to the many questions on my mind about issues of architectural safety, earthquake resistance, and seismic considerations in Chilean building codes and structural design.

First: where is the safest place in the house? Structurally speaking, are there places that people can easily identify that would naturally be stronger than others?

The safest place would be beneath a reinforced concrete lintel, that is, a lintel formed by structural walls and a structural beam (these are usually thicker than a partition and easy to spot in a dwelling). In any case, stay away from tall furniture and open shelves. Running through hallways and staircases is not advisable.

** See the American Red Cross earthquake preparedness guide for more information.

When did Chilean building codes first take seismic activity into account? It would seem that perhaps even before the official codes existed, people knew not to construct higher than 1 story, or 2 at the most. Were the first building codes related to a specific earthquake?

The Chilean building code (the “Ley General de Urbanismo y Construcciones,” which falls under the control of the Ministry of Housing and Urban Development) was enforced after the Chillán earthquake in 1939 and perfected after the Valdivia earthquake in 1960. Many buildings of up to 9 floors were erected before 1960 (think of the vast downtown area, under the Brunner ordinance). The first tall building in Chile was the Endesa Tower on Santa Rosa Avenue. The improved code of 1960 stipulates that buildings must withstand a magnitude 9 earthquake or higher without collapsing, even if they are damaged so badly they must later be condemned.

Edificio Alto Río, Concepción, Chile

The new--and formerly vertical--14-story Alto Río building in Concepción, Chile, post earthquake

Despite the code, some buildings did fall, most notably the one in Maipú and the other in Concepción. In your opinion, was this due to problems with the code, code enforcement, or something else?

Code enforcement, clearly. This appears to be a matter of  a relaxation in building procedures and hasty construction, which is the  responsibility of builders and developers, rather than a matter of structural design or the quality of materials, which are not an issue here. As part of the deregulation policies of the neoliberal economic model enacted in the 1980s, local authorities and professional associations were deprived of direct on-site supervision powers in the 1980s.

Structural design in Chile is reliable, based on state-of-the-art technologies, and has even developed innovations adopted in other regions around the world.

Do you anticipate adjustments to the building code following this quake?

I hope so, particularly in the project revision and on-site supervision powers of local authorities and professional associations, all of which existed until the 1980s.

How have the technology and theories changed over the years with respect to architecture in areas at risk for earthquakes?

The basic theoretical principles are rather simple and date back to the beginning of civilization. The use of reinforced concrete has been the single most important improvement in seismic construction. Other improvements include compulsory analysis of soil mechanics, sophisticated structural performance modeling, and the use of shock-absorbing devices, especially in high-rise buildings.

How does Chile stand up in terms of its building codes and architecture in general with respect to the other countries in the earthquake-prone Pacific Rim–also known as the Pacific Ring of Fire?

Chile’s building code is based on the most stringent international norms and regulates structural engineering design standards as well as the quality of building materials and construction procedures.

Do Chilean architectural students have courses in seismology?

Students are trained in basic structural design. They are expected to understand the general criteria required. However, structural stability, particularly in larger buildings, is always the responsibility of a structural engineer.

How well do you think Chile’s buildings did in the face of this 8.8 earthquake? Would San Francisco or Tokyo have fared better?  I keep wondering what the outcome would have been if something like this had happened in New York, for example. Of course there’s no real reason to build anti-seismic structures there, but do building codes in areas at less risk to earthquakes take similar precautions anyway?

Modern buildings seem to have fared very well. Only one building actually collapsed (the one in Concepción). It toppled rather than crumbled, which appears to be more of a foundation design problem. The few buildings that sustained heavy damage and may be condemned (fewer than 30 in Santiago, according to unofficial information) did not collapse, which is the ultimate purpose of seismic design.

All buildings, and especially high-rises, regardless of their location in the world, must be designed to withstand overloads and lateral forces, such as earthquakes or strong winds.

You told me you were working on ways to protect national heritage–patrimonio nacional–with respect to its adobe architecture. Could you please explain a bit? I’ve heard that the original vernacular Chilean colonial-style home developed precisely because it WAS earthquake resistant, but that over time people started reducing the thickness of the walls and changing the design and that is why adobe homes are no longer considered safe. Your thoughts on that?

I’m concerned with not just the protection of surviving adobe structures, but the identical reconstruction of fallen buildings so that they will maintain their general appearance and urban character, as they are an intrinsic part of our national cultural identity. This is a difficult task, because adobe has always been a very limited material in terms of resistance to earthquakes.

Adobe was the only and most efficient material available for centuries, and they built with it as best as they could. Historically accurate earthquake-proof reconstruction would demand the use of mixed building techniques, for example with concealed supporting structures made of wood or steel, resistant wrapping materials, or some reinforced concrete elements. One serious hurdle I see is financial, as adobe buildings are much larger and bulkier than the contemporary standards. In any case, the most resistant structure would always be made out of reinforced concrete.

For more information, see Sebastian Gray’s New York Times Op-Ed piece: Santiago Stands Firm, March 1, 2010, in which he discusses the earthquake and the great loss of national heritage. He concludes by saying:
For Chilean architects, this is the challenge of a lifetime: to restore beauty, to preserve history, to build sensibly.”

30 responses to “Chile’s Earthquake: An Architect’s Perspective

  1. Great and informative post! It was really interesting for me to read this!

  2. Thanks- I figured if I was wondering about these things, other people must be too!

  3. I’d be interested to know the professor’s opinion about the damage sustained by Santiago’s airport; the one location that should be the last to fall. By all accounts it looks like a modern building and therefore should have been subject to the new building codes.

    As it happens, the devastation expected after an 8.8 never materialised and the services of the airport were not as important……but they could’ve been.

    Does he think somebody’s head should roll for this?

  4. Good question, and yes, this is a fairly new building–mid-1990s, if I recall correctly.

  5. Regarding the airport, the bearing structure and large roof spans resisted without any damage whatsoever. Runways and control tower resisted as well. As you know, the airport was already functional a few days later.

    Some secondary (non-bearing) elements, such as outdoor pedestrian bridges and indoor freestanding hydraulic elevator cases, collapsed or were displaced. Regardless the magnitude of the earthquake, collapse of these elements is not acceptable.

    As for the finishes, most notably suspended ceilings and A/C installations, they did very poorly, and deserve an inquiry.

    It is worth noting that a preliminary report issued by the Facultad de Ciencias Físicas y Matemáticas of the Universidad de Chile shows that this earthquake’s accelerations in all three axes (X,Y, Z) surpassed the allowances of current seismic Chilean Norm NCh 433, which may explain the secondary damage sustained in countless modern buildings. This is likely to become a defining issue when looking for professional responsibilities, and should also prompt future revision of the norm.

  6. Thank you Sebastian. I was just looking for information about the concept of acceleration with respect to earthquakes (the US Geological Survey site is an excellent source of information, though I can’t say I really understand it. It seems to be related to how quickly the movement changes direction?
    We were all very fortunate that this earthquake occurred in the middle of the night, at a time when there were very few, if any, people in the airport, on the highways, in the streets, etc. Had it happened during the day, the consequences in human lives and injuries would obviously have been much worse, although perhaps the the tsunami might have claimed fewer lives. I certainly hope that if any good comes out of this event, it is that the norms and codes become stronger and more rigorously enforced.

  7. Very interesting, and good to know, all of it. I had never heard about the nine-story issue, which, had it never been overcome, would have given Santiago a different skyline and population density.

    Fascinating. And I had seen that photo of the buildning in Conce and assumed that it was a broad building that had split down the middle. I can’t imagine what that was like for people in and near the building.

  8. Yes, I had the same impression that it was a wide building, but today I discovered that it was a high rise! You can find before and after shots here: http://www.chw.net/foro/off-topic-f16/309633-edificio-alto-rio-concepcion-antes-despues.html

  9. I just asked Sebastian how to tell if a wall is load bearing and how to devise a safety plan, and he replied:
    “You need take a good look at your apartment and building floor plans or walk through them with an architect. You can get
    copies at the Dirección de Obras Municipales (DOM) in your municipality. The plans will show you which walls are structural (thicker). Everybody should be aware of how their dwellings are built!”

  10. So interesting and informative. I have been reading a little about the triangle of life/triangle of death controversy. When I first saw that email that was circulating, it made sense…until I read the problematic assumptions it is based on and the counter-arguments. Of course, many of the official recommendations seem to presuppose that you don’t have to take care of anyone else but yourself. I would be crawling for my kids’ rooms first.

    I also had the impression that the toppled building was wide and split in half– I was horrified to see that it had in fact just fell over.

  11. I agree with you Annje–kids come first, whatever the risk… I even had a dream child last night and was very upset when I woke up with a jolt and at first felt I had to get back to save her from some destruction or other in Turkey–that’s the problem with seeing a movie like Avatar right after a major earthquake–the mother instinct kicks in even for dream kids!

  12. Good editorial in the NYT. I was happy to see it, but wondering if indeed heads will roll. A cynics perspective about the most recent building boom in Chile is that low quality materials were used in some buildings to lower fixed costs and maximize profit, the last of which among Chilean companies is an art.

    You addressed the issues of hasty construction and lack of code enforcement from the 1980s but while the dictatorship is a good whipping boy for all that ever goes wrong, la Concertación has been in power since 1990. Until now.

    I read somewhere, i may be incorrect, that newly appointed positions from the Piñera government overseeing Stgo. and Conce are folks from the building industry.

    The ball is in Piñera’s court. I imagine many people are reclamando desperately about the faulty consturction of their buildings. It will be interesting to see how the new government, a moderate? conservative will address issues like regulations of buildings, reconstruction of cities and towns, and formal complaints to private construction companies.

  13. Hi Tomas- Yes, heads have already rolled (Carmen Fernández, the former director of ONEMI was one of the first)… and I suspect Chile will have its own London Tower full of heads on stakes before this is done… Piñera and crew have their work cut out for them… and tonight’s nation-wide blackout just added more fuel to the fire! These are definitely interesting times (as they always seem to be in Chile!)… Xtreme 24-7 / 365!

  14. “Other improvements include compulsory soil mechanic analysis, sophisticated structural performance modeling, and the use of shock-absorbing devices”

    Those all sound like classes that Seba had to take in college.

    And I don’t understand — isn’t an architect the one who designs a building? So why would a structural engineer be the one responsible?

  15. Great info Margaret…

  16. Kyle:

    Although commonly mistaken, architecture and construction are not the same thing. There can be sound construction without any architecture (call it either vernacular, trivial or downright ugly). While architecture deals with and understands every discipline involved in construction, its trascendental purpose is mainly conceptual (issues of beauty, comfort, symbolic representation, efficiency, etc.) Of course, good architecture always implies good construction.

    A building is designed by many professionals and technicians who work simultaneously and in close collaboration, all under the driving concept of an architect (who is in turn at the service of a client, such as a developer or investor). Each one of these professionals has a liability in their specific role in the project, and there’s always great feedback among them. A given team of designers is committed throughout construction and, even for a small house, is usually comprised of:

    -Architect
    -Structural Engineer
    -Electrical Engineer
    -Plumbing Engineer (water, sewage and gas)
    -HVAC Engineer (Heating, ventilation, air conditioning)
    -Lighting designer
    -Landscape designer

    Other professionals involved and liable after the construction phase are the General Contractor and the Technical Inspector (usually hired by the client to supervise construction).

    These are not just classes I took in college; this is the reality of everyday life in our professional practice.

  17. Thank you Sebastian for explaining the difference between all the people involved.
    But just to clear up a funny “alcance de nombres” I think Kyle was referring to her husband, your tocayo, when she said “Seba.” I believe he’s an engineer, though I don’t remember what area he specialized in.

  18. Great post. A lot of my post-earthquake questions have been answered! I was going to comment last night, but then the power went out…

    Is it a coincidence that most of the structually damaged high-rises in Vina are on the Plan, which I believe is more sandy? Vina definitley seems to have been/still be in the middle of a building boom.

    Overall, though, I’m pretty darn impressed with how well buildings did in the earthquake. And I hope a way of reconstructing the traditional buildings to modern standards can be found.

  19. Great! I’m glad it was helpful! And I’ll let someone more qualified than me answer the question about Viña.

  20. Sorry! I was wondering if we had already met…

  21. Perfectly understandable confusion!!

  22. Very interesting! Thank you Margaret and Sebastian both! I will be very curious to see how the new government handles the regulation issues. The neo-liberal model calls for less government “intervention” but I would think people will be calling for more stringent regulation.

  23. Personally this is one area that I would like to see tightened up considerably!

  24. One of the biggest dangers I see on a daily basis in Chile is the use of “maestros” for everything with no regulations as to exactly what a maestro is. Anybody can suddenly decide he’s a maestro of cement, wiring, plumbing, welding, anything his heart desires on any given day & when they say they are, everybody believes them & puts them to work. A lot of what I witness is really frightening.

  25. Yes, the maestros. I saw (on another blog) a right wing, less govt intervention guy who happened to be a US contractor wishing for the licensing of maestros. It looks different when you see the affects up close and personal.

  26. Hi Lauri & Laura-
    Ahhh, the maestros… sore subject with me! I’ve had more than my share of bad luck… It’s really hard to get someone qualified to do small projects, so that means you’re left either doing it yourself or depending on “maestros.”
    I certainly understand that small repairs and odd jobs are an important source of income for many people in this country, but it amazes me how many people use them for things like putting on roofs and major plumbing–in large part because architects and contractors don’t want the small jobs… There just doesn’t seem to be a happy medium!

  27. In some cases small repairs might be ok for our “maestros” but since the main causes of house fires here are faulty wiring & gas stoves, both usually jobs done by maestros even simple things are serious. In the last 3 months just in my neighborhood I’ve watched 2 entire houses be built by neighborhood “maestros” & that’s frightening!

  28. Hmmm–I wonder what the deal is with building permits, etc. Do they exist for work done on private homes? Are there inspectors to insure that completed work is safe? I get the impression from what Sebastian said that there are now few (or no) building inspections…
    Sebastian? Can you comment?

  29. I’m certainly not an expert on what laws exist for sure however I read on another site (& possibly here also) that we did use to have inspectors for large buildings but during the Pinochet years “on site” inspections were ended. Also, on the national news one of the engineers stated that building codes don’t apply to private homes & smaller buildings. I’ve never seen any type of inspection being done either so ….. What does Sebastion say??

  30. Thanks for the article – very informative, and also for the link to the Times article by Sebastian. I’ve just moved to Chile and have (understandably) been wondering what to look for during our apartment search; but saw the article just after signing for our place. Now at least we feel a bit reassured that we should be ok in a relatively new (17 yrs old) 7-story building built with reinforced concrete, but will also look for the supporting beams you mentioned in your follow up Margaret. My only unanswered question is: if the regulations say it has to be able to withstand a “magnitude 9” earthquake, what about those above that? In 1960 it was 9.5, so just looking for a bit more precision (and security🙂. Thanks.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s