Engineers worldwide will learn much from watching the processes and back-up precautions embraced by the resilient people and industries in Japan as they rebuild, restructure, and in many cases are able to maintain operations through the aftermath of the recent Earthquakes and Tsunami disasters. Their rebuilding efforts started before the Tsunami washed back out to sea, and the systems they engineered to survive the quakes have delivered astounding service.
Earthquakes are more common in Japan than they are in much of the rest of the world. So engineers have spent a lot of time thinking about how to make buildings that won't collapse during quakes. That may be one reason why the recent earthquake in Japan wasn't worse.
Did you see the videos from the downtown area that shows the high rise buildings actually swaying during the quake? (Skyscrapers, High rise buildings swaying) This impressive video actually records the result of fully employing the earthquake design principles that have been around for decades. Most engineers know about them, but in Japan they actually execute the design and construction with them. After the quake, the buildings are still standing!
From PRI on March 14th: "In many places in the world where you don't have earthquakes, people make the structures to be fairly strong and durable against wind and the weather," Stephen Mahin, director of the Pacific Earthquake Engineering Research Center told PRI's Here and Now. "But they're built in a way that if you bend them, they'd break like piece of chalk. So they're fairly stiff and strong, but brittle."
In Japan and California, engineers have started building structures that are more ductile. Mahin describes it like a paperclip: "you can bend it, and at some point it gives way but it doesn't break. And you can bend it over and it will stay in that misplaced shape."
"The idea is to allow that structure sway but not to break," Mahin says. That design is what caused many buildings to shake rather violently, but not fall down. Mahin says, "tall buildings especially sway back and forth quite aggressively and frighten people understandably."
In spite of the magnitude of Japan's earthquake, or what some people are calling a "megaquake," Mahin says: "It seems that most of the new structures were able to go through the earthquake." Some of that can be attributed to this flexibility being designed into the buildings.
"A lot of these ideas have only been developed fully in the last two or three decades," Mahin says. Some of the older, concrete buildings in Japan were likely at risk. But the Japanese government had been taking steps to retrofit old buildings to make them more earthquake resistant. California has been takings similar steps as well.
I don’t think that any of us could ask for a higher testament to the earthquake design principles than what our friends in Japan just endured. Count me in on the “I’m convinced” list!
By K.B. Elliott
K. B. Elliott is a freelance writer for Engineer-Jobs.com. Working many related positions in the Detroit area for over 30 years gives him a unique perspective on the process. To read more of his blogs, please go to Engineer-Jobsblog.com, and be sure to check out the postings for jobs in nearly any industry at Nexxt
Are you ready for that next job as a Professional Engineer? Find your niche position at Engineer-Jobs.com .