Construction Informer

People may have to stop referencing the Three Little Pigs story while extolling the virtues of one building material over another. It appears that straw may be just as resilient as brick.

Darcey Donovan, a civil engineer, and the Reno alumna of the University of Nevada, built a straw house that survived the 82-ton force of an earthquake simulation. The house was a full-scale, 14-foot by 14-foot replica of the kinds of houses Donovan has been building in Pakistan. It took seven increasingly forceful quake simulations to cause the house to sway and crack at the seams – but it stayed standing.

Donovan described her work in Pakistan as an effort to increase survival rates for people who have traditionally lived in housing that doesn’t stand up to quakes. A major challenge she explained is in making the housing affordable and earthquake resistant.

Straw bale houses are used around the world, but those have posts and beams for support and rely on energy-intensive materials, skilled labor and complex machinery, making it unaffordable for the poor,” Donovan said. “In our design, the straw bales are the support, and not just for insulation. Our design is half the cost of conventional earthquake-safe construction in Pakistan. The materials we use — clay soil, straw and gravel — are readily available; and we utilize unskilled labor in the construction.

Donovan also claims the structures are 80 percent more energy efficient while being 50 percent of the cost of conventional buildings.

How Much Stimulation Will Your School District Lose? Or, maybe by now it should read – Did Lose. Pro Publica has put up a tool on the Web where you can see how much construction money won’t be flowing to your school system if the Senate version of the stimulus package gets passed. Some builders may have to forego those new tape measures since even in small communities the money that won’t be flowing is significant. I checked on a town with a population of 20,000 that is nearby and the amount was more than $1.5 million.

Earthquake Proofing According to Purdue: In light of the disastrous collapses of schools and other public buildings around the world as a result of earthquakes some civil engineers at Purdue have looked at building failures and found a built-in flaw that makes buildings more susceptible to earthquake damage. Buildings in Turkey, China and Latin America use too many partial height walls between structural columns. That leads to weak points that could easily be strengthened by replacing some windows with ordinary masonry bricks.

Brazil To Build Its Way Out Of Economic Doldrums: Government in Brazil plans to build a million homes and increase government-backed home loans by 42 percent in order to reactivate the domestic construction sector. The Brazilian President is bent on getting a package that generates more jobs while building cheaper housing for poor people.

Got an Infection? Eat Your Plaster. Chinese scientists are putting the finishing touches on a self-sanitizing building plaster that is more powerful than penicillin. Dubbed “supramolecular” the material can be used for wall coatings, paints and art work, to name a few applications. It is capable of killing five types of disease-causing bacteria and controls the growth of four other kinds of bacteria better than penicillin.

One part of the country’s flirtation with rebuilding its infrastructure could be a new style of bridge in certain locales. Called a flexible bridge, it is engineered to withstand an 8.0 earthquake.

Engineers at the University of Nevada built and tested a 200 ton model that survived 10 seconds of shaking. Its resilience is attributed to the reinforcement in the concrete – smart nickel titanium or Nitinol. This material has shape memory (perhaps much like that material recovered from the alien ship crash at Roswell more than 50 years ago). Because it remembers the shape it was cast into, after being deformed it springs back to that original shape. These Nitinol bars are used in critical places in the bridge’s structure, like in the columns.

Apparently, the “dumb” steel used in bridges today, stays deformed after earthquake shocks often causing the entire bridge to be rebuilt. The test also suggests that Nitinol might be a great material for the cables of suspension bridges.