[GSBN] natural building in haiti, pt 2

[ejgeorge at riseup.net]

Another Haiti email, including a recent article from Science magazine:

from Mark Piepkorn:

I have to confess a lot of ignorance about Haiti, but that doesn't dampen my sympathy. 
And I've been seeing a lot of the same in various lists and groups that have people with 
pet materials and methods gearing up to supply (what most often seems to be inadequate) 
knowledge and muscle for strawbale, cob, adobe, earthbag, shipping containers (talk about 
inflicting evil with good intentions), tents, and more. I have huge appreciation for Andy 
- not just that he's doing something, but for the way he's going about it.

Apparently traditional housing in the Port Au Prince area was of lightweight, easily 
worked palm wood - typically two rooms, single story, with a porch, like Andy described. 
(Materials used in other parts of Haiti varied according to what was on hand, including 
stone and wattle-and-daub.) I haven't been able to find a breakdown of failure rates 
between homes built of various types of materials... everything just points fingers at 
the failures of concrete houses - which evidently could have withstood the quake if they 
were properly engineered and built for it. (I'm not advocating the use of concrete, I'm 
just sayin'.) I worry that other heavy materials, including earth-based ones, won't fare 
any better in preventing loss of life the next event if they're also not engineered for 
seismic resistance. (Shipping containers would most likely be great in that aspect, if 
hellish on every other way.)

I know seismic design is right up there on Andy's list. I hope that the reinforcing and 
other details aren't skimped on or omitted down the road like they have been in the 
ubiquitous concrete buildings there.

There's not enough palm trees to support a return to indigenous housing. Introducing 
strawbale as an option seems to make more sense than most others. That, and other 
notions, are suggested in a recent article in Science magazine - pasted below since it's 
a subscription-required site.

//Science
5 February 2010:
Vol. 327. no. 5966, pp. 638 - 639
DOI: 10.1126/science.327.5966.638

News Focus
Rebuilding: From the Bottom Up

Sam Kean

Haiti needs robust buildings that cost little and are acceptable to locals. Can 
scientists provide them?

Rebuilding the cities of Haiti to withstand natural disasters seems both simple and 
impossible. Engineers in the United States, Europe, and Japan have known for decades how 
to buttress buildings against earthquakes. The 1989 quake near San Francisco, California, 
for example---although it had the same magnitude as the Haiti tremor (7.0)---killed only 
63 people. But Haiti simply doesn't have the money to adopt first-class solutions. 
Although various governments pledged to support Haiti over the next decade at a meeting 
in Montreal, Canada, in late January (Haiti is seeking $3 billion), Haiti has very little 
time to develop a rebuilding plan. With perhaps 170,000 dead and most survivors living 
outdoors and scared to enter standing structures, Port-au-Prince cannot wait. 
Nevertheless, scientists do see quick and cheap ways to rebuild---if Haiti is willing and 
able to accept foreign ideas.

Long vulnerable to disaster, Haiti has seen the danger grow in recent years, says Pierre 
Fouché, a Haitian citizen studying at the University at Buffalo's graduate school and, he 
says, one of Haiti's few earthquake engineers. Jobs drew millions to Port-au-Prince from 
rural areas, and the crowding forced people to build homes on dangerous slopes or 
unstable wetlands. He says the government lacked the power to dissuade anyone: "You just 
select a place to live and put up a house there, and no one is going to say anything."

Compounding that problem, the buildings themselves are made of concrete that's heavy and 
brittle, the worst combination in an earthquake. People also tend to skimp on 
reinforcements like rebar, partly because no one in Haiti enforces building codes, Fouché 
says. Even when people do try to build safe houses, they cannot always trust the material 
they buy: There are already reports of people wrenching steel out of fallen buildings 
after the earthquake, bending it straight, and reselling the brittle, compromised rods.

Buildings toppled for less censurable reasons, too. Some were designed to withstand a 
more common natural threat, the sheer force of hurricane winds, not the back-and-forth 
shaking of earthquakes. Hurricane winds also produce a lift force that can pull rooftops 
off. Heavy roofs were therefore popular, but they became deadly during the quake. Perhaps 
most poignantly, people in Haiti saw modern concrete houses as a status symbol and 
aspired to have one. Indeed, the earthquake devastated both upper- and lower-class 
neighborhoods in Port-au-Prince. Both the shanties and the presidential palace fell.

New ideas

Much research into earthquake-resistant buildings today focuses on fine structural 
damage---research almost too sophisticated to apply to Haiti. Before he began developing 
ideas for cheap homes in seismically vulnerable countries, John van de Lindt, a civil 
engineer at Colorado State University, Fort Collins, studied topics such as how to alter 
the patterns of nails in wooden houses, mostly to prevent small frame shifts. He admits, 
"In Haiti, this stuff is overkill. You're basically trying to prevent collapses."

Some engineers want to rethink the basic materials used in developing countries. Darcey 
Donovan advocates replacing concrete walls with load-bearing straw bales. Her nonprofit 
group, Pakistan Straw Bale and Appropriate Building, erects 7.3-m-by-7.3-m houses in 
northwest Pakistan, which was ravaged by an earthquake in 2005. The bales are stacked and 
bound together top to bottom with a fishnet, which keeps them from slipping apart during 
shaking, then plastered over. Her team has built 11 houses so far, with six more coming. 
The design recently survived, with minimal damage, a violent test on a shake table, a 
large platform that simulates earthquakes. Because the tough, fibrous plants used for 
straw are ubiquitous, Donovan believes the bale design could easily be exported, and her 
team is discussing traveling to Haiti.

Donovan would like to eliminate concrete, but other engineers don't mind it, provided 
people use it safely. James Kelly, professor emeritus of civil engineering at the 
University of California, Berkeley, expects people in Haiti to continue building with 
concrete because it's cheap and easy to shape into blocks, and because deforestation has 
left few other materials. So Kelly focuses on keeping concrete buildings upright with 
rubber isolators to absorb shocks.

Many buildings in California and Japan sit on hundreds of rubber pads that absorb seismic 
energy by deforming, as opposed to cracking or shifting. A building on a rubber 
foundation essentially shakes independently of the ground and at a slower frequency, 
which helps brittle walls survive intact. But because isolators are usually custom-made 
and contain steel, they cost up to $10,000 apiece. Kelly designed cheaper isolators for a 
few hundred dollars, with embedded carbon fibers instead of steel. Carbon preserves the 
material's strength but makes it easy to mass-produce and cut into strips, which can be 
used in the foundations of small homes.

Van de Lindt works on a similar isolator design, but with recycled rubber tires instead 
of strips. And beyond redesigning walls and foundations---which only help new homes---Van 
de Lindt wants to retrofit existing homes. He says that drilling holes into concrete 
walls and inserting bamboo buttresses 1.3 meters long would keep many modest-sized homes 
in developing countries standing during quakes. This isn't sophisticated science, "it's 
more a social question," van de Lindt acknowledges: "Can we provide fixes that may not be 
perfect but are much, much better than anything they have now?"

In addition to rethinking building designs in Haiti, scientists are studying risks in the 
land itself. Marc Levy, an environmental management expert at Columbia University, was in 
Port-au-Prince when the earthquake struck. The building next door toppled, and he saw 
walls fallen over onto cars and pedestrians. He now worries about a secondary disaster: 
landslides, which usually happen during the rainy season starting in May. "The pattern of 
risk is going to shift," he says. "Areas not due to experience a catastrophic landslide 
for a decade" may have "moved to the top of the queue because of the loosening of the 
soil."

To address concerns like these, a team led by Brady Cox, a civil engineer at the 
University of Arkansas, Fayetteville, who surveys disaster zones worldwide, is currently 
mapping the soil in Haiti. They're doing so with the most sophisticated equipment they 
could ship in. At each site, they plant a sensor in the ground, walk about 30 meters 
away, and begin banging on the ground with a hammer. The energy of the blows propagates 
through the soil, and the sensor records higher or lower readings depending on how 
compact it is.

Cox says two types of soils in Haiti are vulnerable to earthquake damage. First is wet, 
sandy soil, which shifts unpredictably because sand grains, when shaken, grow compact and 
squeeze water out into confined spaces. Water then builds up underground and erupts like 
a geyser as the pressure grows. Cox suspects that this process opened the rifts along 
Port-au-Prince's harbor. Second is softer soil like clay, which shakes violently when the 
energy waves from an earthquake, straitjacketed in stiff bedrock underground, suddenly 
emerge in the softer material. Cox is mapping these types of soil not to tell Haitians 
where to avoid developing as much as to provide sorely lacking information. "We have the 
ability to design [buildings] for all these soil types," he says. "You just have to 
understand what type's there."

Small window

Even if scientists hit on a perfect design, other challenges remain. People must actually 
use the design---and quickly.

Georg Pegels, a civil engineer at the University of Wuppertal in Germany, has helped 
spread safer designs in Iran that rely on diagonal steel beams. Iran lost 30,000 people 
to a 2003 earthquake and experiences quakes of magnitude 6.0 or greater many times a 
decade. Despite the danger, Pegels says people often resisted living in his buildings for 
aesthetic reasons: They didn't like homes different from their neighbors'. Allowing 
artists to decorate the buildings helped convince people to accept them, he notes.

Pegels smartly concentrated on building schools, which gets many people in the community, 
including the next generation, comfortable with the design. His team has built more than 
30 schools so far. In Pakistan, Donovan adds, people actually embrace new designs if they 
see them as status symbols. Some beneficiaries "think of [a straw-bale house] as high 
technology because it's earthquake resistant," she says. "It's all how it's presented."

Pegels also discovered that people often fear that inept or corrupt workers will cheat 
them out of the safe but expensive materials they pay top price for. (He mentioned cases 
of people putting steel in wet cement, showing the reinforcements to customers, then 
secretly pulling the metal out before the cement sets.) So his team builds steel frames 
at a trusted local factory and ships them to the site intact. This allows people to see 
they are getting a safe house. And unlike fully prefabricated homes, it also preserves 
jobs for locals, who fill in the masonry around the skeleton.

Scientists can foresee disaster in many seismically vulnerable countries: Iran, Turkey, 
Indonesia, China. But Haiti's acute need for housing presents a special challenge. Fouché 
fears his fellow Haitians will fall back on whatever design is most expedient: "If 
nothing is done quickly to set a new framework, the people there are going to do the same 
thing," he says. "They think, 'A big earthquake just happened, so there isn't going to be 
another one for a while.'"

Fouché knows there's a short time to establish the new framework. He has not visited 
Haiti since the earthquake but hopes he will have a chance to return after he has his 
degree and finally help Haiti build properly. 
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