Haiti needs seismic-resistant buildings
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The massive 7.3-magnitude earthquake that hit Haiti on Tuesday could have resulted in less fatalities and destruction with better-engineered buildings and structures.
This is the argument of seismology engineer Sarada Sarma of Imperial College London’s Department of Civil and Environmental Engineering.
‘The only way to avoid death and destruction in big earthquakes is to build structures with proper seismic-resistant design,’ he said.
According to the Red Cross, thousands have been killed as a result of the earthquake, which hit the capital Port-au-Prince and other areas of the country.
The quake, which is the worst to strike the island in more than 200 years, wrecked and demolished numerous buildings, including the presidential palace and the UN headquarters.
Sarma said that most of these buildings were ‘un-engineered’ designs based mostly on reinforced concrete.
‘In such a poor country, they really should not go for un-engineered designs,’ he said. ‘Instead of reinforced concrete, they should use timbers for beams and columns and joints. While they would not last long, they will withstand earthquakes.’
Yet Sarma warned that those involved in the rebuilding of buildings and structures in Haiti should not consider over-engineering designs to withstand bigger earthquakes because it will end up being too costly.
‘They need to try and build them in a way so that they become failsafe,’ he said. ‘So the structure will fail after an earthquake, but it will fail in a safe way that does not end lives.’
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Readers' comments (15)
Stephen Mosley | 18 Jan 2010 12:56 pm
America and Japan have spent a lot of money developing earthquake resistant structures but I doubt Haiti could have afforded to engage the experts on a large scale. What is more, unless the developed world can be persuaded to share the technology involved without charging a premium, somehow I doubt that Haiti will build anything other than conventional structures in the near future. Perhaps its a case of the way international aid is used to rebuild a country is more important than the act of rebuilding itself?
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Kerry Green | 18 Jan 2010 1:15 pm
I think it's important to at least use a midpoint solution. That is to use cross bracing and stick to single story buildings. Timber is great as at least it can flex. The concrete buildings that collapsed are just not acceptable for any country where quakes occur. Schools, and hospitals where high numbers of people are concentrated must have higher safety. I suspect that the problems do not occur from lack of knowledge but come from poor planning control and profiteering.
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Marcus Gibson | 18 Jan 2010 1:26 pm
Contrary to Mr Sarma's view, timber-framed buildings last a very long time, and would be ideal for Haiti as a long-term habitation model. Haiti now needs 250,000 pre-fab buildings. Who is going to supply them? About 15 years ago Scandinavia paid for 20,000 Bosnian Muslims to return home after the former had delivered thousands of pre-fab homes for them to live in, post-conflict. We can do it all again.
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Neil Tilley | 18 Jan 2010 1:36 pm
Buildings with seismic capability are needed that is for sure and local resources will play a part. Reinforced concrete is fine to a point but it is clear from the pictures on the news that there is insufficient rebar used and I would suspect the quality of the concrete wouldn't stand up to muster either. Steel would be an option as has been shown in the USA after Northridge but limited perhaps by the need for importing. Timber has the local angle but given that corners will undoubtedly be cut I would have concerns about the fire aspect, just consider the fires in the UK over the past few months. Important buildings need to be designed to resist earthquakes i.e. Government buildings, schools, hospitals, embassies so that the coordination effort post quake can be deployed quickly.
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Colum McCavana | 18 Jan 2010 2:48 pm
The discussion about Haiti regarding building structures may be appropriate for larger and public buildings, control of which may be possible. With people so poor, construction of shanty towns was the norm for the ordinary person, which is what resulted in so much damage and death. Building control standards may have been non-existent, in practice and perhaps in statute? Unless the people find an organized economic alternative (aid?), they may continue doing what they always have done.
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Philip Spiers | 18 Jan 2010 6:18 pm
The Structural Engineering requirements for seismic resistant structures are generally well understood and documented by Engineers and Buidling Regulation Authorities worldwide.
For large structures and public buildings the analysis can be complex. However for small to medium size buildings simple rules for seismic resistance are available which relate to minimum wall areas and and their geometric distribution on building plan.
Adherence to these rules would significantly reduce building failures with little or no additional construction cost. Witness to this is that buildings unaffected by the same earthquake event sit, undamaged, adjacent to similar sized buildings that have catastrophically failed.
Aid, Disaster Relief, and Overseas Development Agencies in particular should insist on a programme of basic Siesmic Design and Risk Assessment for water works, schools, hospitals, and places where large numbers of people congregate, as a condition allied to any form of support in high Seismic risk areas.
The financial provision for such seismic design, simple building regulation, and risk assessment would be significantly less than the aid expended on rescue, disaster relief, medical attention, and reconstruction and would more humanely utilised.
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olu | 18 Jan 2010 10:22 pm
Ground investigation should be carried out first before taking any decision on the types of building to be employed as discussed by others contributors above. This will enable whether to go for stiff or flexible structures depending on the soil capacity. The ideal is that if the soil is stiff, then flexible structure must be provide in order to prevent resonance and vice-versa. Though, there other factors that a good earthquake engineer will consider before selecting appropriate techniques for the design of earthquake-resistant structures.
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JG | 19 Jan 2010 6:49 am
"The British government has said it will treble its aid to Haiti to £20m ($32m)."
We should insist that all our "aid" is delivered in kind, better designed/earthquake-proof buildings, water supplies, sustainable farming etc. Using only British or local input, supervised by British firms.
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D B LeChat | 22 Jan 2010 2:17 pm
I'm sure that somewhere out there are some Japanese architects who are familiar with ancient construction techniques. For at least 1,000 years, they have been building structures that are both dirt-cheap in materials and earthquake-resistant.
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Jerry Abbott P.E. | 23 Jan 2010 0:05 am
There is NO Wood in Haiti! Wood buildings would be far more costly than anyone can imagine.
One major failing was the very great mass of the poured concrete roofs in comparison to the mass of the walls. Walls moved with quake, roof mass took more force than the walls could transmit.
Do need stronger walls but also need roof covers with less mass.
Multi-story buildings are a new subject entirely. I address the typical up scale family dwelling.
Jerry Abbott P.E.
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