Stories tagged buildings

In the quest for developing better building methods to withstand hurricane winds, this experiment with about 100 high-powered fans shows what happens to a non-hurricane-proofed home vs. one that's using special building methods. It's estimated the winds got up to 96 mph in this test, equal to a Category 2 hurricane.

Mar
31
2009

The new I-35W bridge: now bigger, stronger, and greener.
The new I-35W bridge: now bigger, stronger, and greener.Courtesy anjouwu
Ever stand on a sidewalk and wonder about the concrete beneath your feet? Where did it come from, and how did this hard grey material get to be pretty much everywhere? Though you may not think about it at all, concrete is used more than any other building material in the world. In fact, concrete is so ubiquitous that the production of concrete contributes 5% of the world's human-caused carbon dioxide emissions to the atmosphere.

Add it all up and it starts to look like concrete is more than just the stuff of sidewalks and building blocks. Concrete is a V.I.P. (which is how I like to refer to Very Important Polluters).

While concrete is a huge contributor of CO2, it also has loads of potential to be an innovative and important "green" material that helps us to build stronger and more environmentally friendly roads, bridges and buildings. This really great article from the New York Times science section explains the basics of concrete chemistry, and how new concrete mixes are being developed that are not just stronger and better for buildings, but that also can scrub carbon from the air.

Here in the Twin Cities we have our own example of cutting-edge concrete in the I-35W bridge, which was built to replace the bridge that collapsed in 2007, killing 13 people. You might not realize it as you pass over this bridge, but it's made of many different mixes of concrete, each developed to do a particular job.

Some of the concrete in the I-35W bridge was mixed and cured (that's what they call the hardening process) to be strong and stable, others to resist the road salts and other effects of weather and climate in Minnesota. The wavy concrete sculptures on the bridge even scrub pollutants from the air, In fact, they stay white because of a chemical process that uses the sun to help break down staining pollutants. Who knew concrete could be so fascinating?!

More Than You Ever Wanted to Know About Concrete

Science Buzz Posts on the I-35W Bridge Collapse

Jun
27
2008

High Bridge power plant smokestack: Things are gonna be different around here...
High Bridge power plant smokestack: Things are gonna be different around here...Courtesy tboard
At 7:30 on Saturday morning, the 570-foot-tall, 5770-ton smokestack of the High Bridge power plant will come crashing down. Xcel Energy’s new gas-fired plant is complete, and the old coal-burning plant, built in 1923, is being torn down. If you want to watch, try the bluff across the river. (Traffic will be stopped on the High Bridge, Randolph Avenue, and Shepard Road.) And be on time: the stack is expected to fall in about 10 seconds. Even the dust cloud should dissipate quickly.

More info from the Star Tribune and the Pioneer Press.

An icon on the skyline
An icon on the skylineCourtesy edkohler

Jun
11
2007

White roofs reflect heat, leaving the structures below cooler: Photo by gadfly pro from Flickr.com
White roofs reflect heat, leaving the structures below cooler: Photo by gadfly pro from Flickr.com

Looking for an easy way to reduce global warming, and save yourself a few bucks in the process? Paint your roof white! Most rooftops in America are black or some other dark color. These absorb heat, making the building hotter and less comfortable. People in the building run fans and air conditioners to cool off. Not only do they spend more on energy, but the power companies have to burn coal and oil to produce the electricity.

But a white roof reflects heat. The building stays cooler, and needs less electricity.

For maximum effect, you should use special heat-reflective materials. And keep the roof clean – dust and dirt darken the roof, reducing its reflective properties.

It’s been estimated that if every roof in the world were white, it would counteract all the global warming of the last 30 years! Now, the authors of this study admit that they used a very simple model – climate is much more complicated than their equations allow – but still, like changing your lightbulbs, this seems like an easy way to start having an impact now. In California, the government is giving rebates to building owners who install cool roofs.