Haiti: Comments About Concrete Technology

Haiti shanties, from CNN.com

In January 19th 2010, Times of India published this article “Haiti earthquake: Architects blame shoddy steel, concrete for destruction”. Architects say that the poor conditions of the structures were the main cause of the death toll.

“ Poor quality concrete and steel explains the extent of quake devastation in Port-au-Prince, a team from the Emergency Architects Foundation said after three days in the Haitian capital.

Architects Patrick Coulombel and Serge Guno said they have visited over 30 key buildings to assess their structural soundness since Tuesday's quake which levelled much of Port-au-Prince”. Architects are afraid of the aftershocks as so many buildings are unsafe, collapsed or not: “shoddy steel reinforced bars, known as rebars, and bad quality concrete surrounding them.

"The rebars are soft, you can bend them with your hand and they're smooth while good rebars should be ridged. As for the concrete, the proportion of cement

is wrong, and there's the bad quality of the aggregate," said Coulombel”

"To save money, people use bad steel, less cement, and then the concrete, it's very technical and complicated (to make), here people aren't able to create good quality concrete," …Coulombel said certain building shapes are less prone to collapse than others -- and recommends pyramid shapes, where possible, even though he admitted "people don't necessarily want to live in a pyramid”.

Star shapes of buildings are better to resist earthquakes –it does not need to be a pyramid-; nobody knows the direction of the earthquake, concrete structures must be tied like rings.

Haitian houses. From http://www.wehaitians.com/mixed_photo_5.jpg

Unicef’s official photo of the year 2008. 21 years old Alice Smeets comes from a slum in Port Au Prince, called the “Cite Soleil” (City of Sun). From www.speedofcreativity.org/

I have been working long years in construction, and if an Argentine architect is considered experienced, he/she must know the concrete technology to perfection, and more than this: what we have to expect from workers pouring concrete and bending rebars, and which quality of materials manufacturers sell.

Trying to save money, sometimes a good quality cement is disregarded and cheapest cement is bought. First thing, the color is different, this is not the same composition, usually more cheap cement has to be used for the mortar. It means that the mortar is not exactly a formula that we follow from books.

Regarding rebars, it is scary to know that Haitian architects could bend them with their hands. Again, this is not enough to follow the drawings on the structural plans. The steel composition could vary, so the rebar “behavior” would not be as expected in calculations. It happened to me to receive silver color rebars for the concrete of a public building under construction; as soon as the workers bent them, they broke in two pieces. Being a new architect of 23 years old, I did not know how to resolve this issue. I called the structural engineer, who explained the rebars were too “ steeled” (“muy aceradas” he said) and the layout of rebars in beams and slabs was changed to use them without bending. It was more money invested in rebars but much less money and time in labor. Why didn't we return the rebars to the manufacturer? It was faster to change the layout than waiting for the new supplies, we couldn’t dismiss the one hundred concrete workers.

Labor is very important in concrete technology. If the quantity of rebars is too heavy, the workers will complain, they would not lift them up as required to allow the stones and mortar enter in the small gaps in between the bars; in consequence, the mortar would not pass through and the rebars could be exposed below the beams. On time, they will oxidate and collapse. A similar issue I’ve seen when workers are pouring concrete; the addition of water makes the mortar more flexible and easy to work with shovels, so it’s the architect or supervisor obligation to see for the correct consistence of the mortar; of course, the quantity of water should vary based on climatic conditions too. And at last, the worst of situations for works without supervision: “concrete” containing trash, wire, pieces of brick inside it, whatever to save the contractor’s money.

Haitian slum from the air. www.gadling.com/photos/haiti-from-the-air/615282/

Haiti from the air. From michael5000.blogspot.com/2008/07. Michael thinks this land must have been left for a park. I agree with him, overpopulation can spread anywhere. Note the different urban fabric of  settlements " under urban regulations", if I can say it....

In another article in CNN.com, January 12th, 2010, I’ve read “Haiti was a 'catastrophe waiting to happen'. Haiti’s ambassador declared that Haiti's infrastructure was among the world's worst even in the best of times; "It was a catastrophe waiting to happen," Raymond Alcide Joseph told CNN from Washington shortly after a 7.0 earthquake leveled parts of his home country”

"Among the numerous factors explaining the extent of the loss of lives and goods are the absence of land use zoning and building guidelines, and comprehensive enforcement mechanisms." The OAS report added Haiti has no national building codes. Former U.S. Ambassador to Haiti Timothy M. Carney told CNN that Port-au-Prince was particularly at risk because it grew rapidly from a population of about 250,000 in the mid-1950s to more than 2 million today, all with little oversight. City planners had called for the surrounding hills to remain undeveloped in order to protect an aquifer. "That didn't happen," Carney said. "People started building up those hillsides." Instead of building concrete structures, they built shanties, he said. "My fear is that they all fell down." Here I see one of the consequences of overpopulation without affordable housing plans of appropriate technology.

Another consideration, even if they used concrete footings, they cannot superimpose to each other. Every foundation has a volume of action around it, to support the construction, this virtual volume cannot be part of another one. Those shanties would have fallen down even in a mudslide or heavy rain. After all, this is not the inhabitants’ fault. Strict regulations in Codes and inspections would have been applied, if people built on the hillsides, overcrowding themselves in the worst conditions, is because they were allowed to. And now, the terrible consequences.

The anecdote, please read in BBC on the news, date december 18th, 2006 (!!!!!!): The UN has made an appeal for $98m (£50.26m) to help Haiti's transition. “The appeal, for the period 2006-2007, aims to strengthen Haiti's government and to help it meet humanitarian needs. It is also aimed at "ensuring that authorities are better prepared in the event of natural disasters", said Joel Boutroue of the UN's Haiti mission.

"All indicators show that Haiti continues to be the poorest country in the northern hemisphere," Mr Boutroue told journalists.

Mr Boutroue, who is the UN's deputy special representative in Haiti, launched the appeal in Geneva.

He said the appeal had three main goals:

to address insecurity in Haiti's shanty towns

to improve the situation in rural areas and thus stem the exodus to the cities

to strengthen the capacity of the government”.

What happened with those goals? It’s been three years since then. Maybe this sad event make Haiti authorities to reflect that new models of decision-making in a group could be developed, with a great respect for individual opinions and necessities.

REFERENCES

Haiti was 'catastrophe waiting to happen' January 12th, 2010
http://www.cnn.com/2010/WORLD/americas/01/12/haiti.earthquake.infrastructure/index.html
Haiti earthquake: Architects blame shoddy steel, concrete for destruction PTI, 19 January 2010, 12:56am IST
http://timesofindia.indiatimes.com/world/rest-of-world/Haiti-earthquake-Architects-blame-shoddy-steel-concrete-for-destruction/articleshow/5474650.cms
The UN has made an appeal for $98m (£50.26m) to help Haiti's transition. Monday, 18 December 2006, 14:01 GMT. From news.bbc.co.uk/2/hi/americas/6190305.stm