Many schools are designed like the building at left, above, with masonry halfway up the space between columns and windows above. In an earthquake this can cause the columns to bend and break at the midpoint. A stiffer, safer design results by using the same amount of masonry, but filling the gap between one pair of columns, and having windows filling the next (video here), according to Purdue University engineers. (Credit: Santiago Pujol, Purdue)An important theme of Dot Earth is limiting losses from inevitable disasters — what I call “hard knocks.” As the human population heads toward 9 billion, more or less, with most of the growth coming in struggling places, unless more is done to boost resilience to known hazards — earthquakes included — there will be ever more wrenching imagery like that out of China (and Myanmar, as well).
Students in a new quake-resistant schoolroom in Balakot, Pakistan. The country saw 17,000 students and teachers die in an earthquake in 2005. (Credit: Swiss Agency for Development and Cooperation)On the earthquake front, a global network of engineers, activists, parents, earth scientists, development officials, builders and others has for years been trying to push countries and communities to make schools and other keystone structures less likely to collapse into rubble in an earthquake. In my Science Times story this week, they say the impediments to building safer schools are more social than structural. Many of the biggest problems, they say, are with institutions, the lack of oversight and inspection, the lack of accountability. The basics of earthquake engineering are as simple as the diagram above (more on that below, including a neat little video clip).
The biggest hurdle may be the same one that has made it hard for people to work now to limit human-caused climate disruption: a tendency for societies to deeply discount long-term, but potentially catastrophic risks.
For earthquake dangers, at least, once society “gets it” (hopefully not just after some local disaster, experts say), changes in design and materials are very straightforward — and often simply a matter of rearranging a conventional assortment of materials. The illustration at the top of this post, and the video below, show how engineers at Purdue University, simply by filling the gap between two adjacent columns fully with brick and mortar, made a full-scale model of a typical three-story structure twice as strong and five times as stiff.
Here’s a half-minute video clip provided by Purdue that shows the test structure, shown to be unsafe without the masonry walls, easily withstood an earthquake-style jolt with the modification.
Often school buildings are designed in the most vulnerable way, with walls rising only halfway up spaces between columns and the rest of the space taken up by weak windows. Simply changing the configuration to have alternating column gaps filled completely could greatly cut the tendency of such columns to shear or buckle sideways in an earthquake, the Purdue researchers say.
Adding simple walls to make stiffer buildings is one route to earthquake resilience, Santiago Pujol, one of the Purdue engineers, told me. In areas with more money and materials, another route is making buildings lighter and more flexible.
One way or the other, it’s clear that moving to a world that is resilient against hard knocks from a world of “rubble in waiting” — as one Caltech seismologist calls many cities in quake hot zones today — is more a matter of awareness and will than wealth.
I encourage you to look at the map we created for the Science Times story showing numbers of school-age children in places with big earthquake threats. Do you know anyone with children in schools in Oregon, British Columbia, Washington state, poorer school districts in California, India, or other known seismic hot spots?
Send this post their way.
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