How Much Does Your Building Weigh?

Architects struggling to get in touch with their inner environmentalist may need to look no further than the weight of their buildings.

I'm heading back from New York City, after an Imaginit-hosted event on sustainability in architecture. I'm composing this on an airplane. Airlines are slavishly weight conscious (a trait not shared by my 300 lb neighbor who is very much in my personal space). The building industry may do well to copy the airlines' lead. After all, less bulding materials equal less trees being cut for lumber, less earth ripped up to make concrete and gather ore, and less energy used to create steel.

Duh, you say? Yeah, I know, it seems obvious. Yet, weight optimization -- a requirement for just about every part that flies --is a rarity for things that sit on the ground. While a slender skywalk may have a FEA done (after all who wants another Kansas City hotel disaster?), most build structures seem incredibly overdesigned -- and weighty. Concrete is poured by the truckload and massive I-beams are in place to support circus elephant acts on every floor.

A ThorntonTomasetti-designed stadium (top), which relies on structural members in tension, may be an order of magnitude less weighty than Beijings's famous birds nest stadium, which doesn't.

So forget the living roof, the epitome of green design, even if you are trying to get on the cover of Architecture magazine, there is a substantial amount of man made material used in the construction of a living room. It might take a hundred years before the environmental benefits of a living roof negate the cost of creating it. 

Shaving tons of your next high rise may not get you any prizes. But at least you and your inner environmentalist will know you did the right thing.

Comments

[stugod]

in light of the recession you will continue to see over design and lots of it in the public sector hmmmmm

[Brian D]

I think it is also worth bearing in mind that least mass does not equal least cost or least environmental impact: much of the cost/impact relates to the method of construction, which can be far higher for slender structures unable to support themselves until complete. Also note that most of an occupied building's environmental impact occurs during use, not construction, and a high thermal mass can mitigate the operating costs considerably.

[ralphg]

As for former professional engineer, I can say that structures are overdesigned to handle things airplanes don't need to worry about, such as earthquakes, hurricanes, and the like.

Considering the liability that engineers work under, they'd rather "Mother" Earth suffers than themselves.