When an earthquake hits, engineers and other qualified experts afterwards must evaluate a building’s structural integrity, a process that can take days, or even longer depending on how severe the quake was. This is vexing to any of the building’s occupants displaced by the post-quake safety evaluation. But there’s typically no other way to ensure a structure is safe to re-enter, or even to know definitively whether any damage happened. Fortunately, affordable technology is now available that makes it faster and easier to detect damage after a quake.
Pasadena-based Kinemetrics is one company specializing in earthquake and building monitoring technology. It offers sensor-based systems installed throughout a building which gather and transmit seismic data, measuring an earthquake’s severity, duration and more.
Using this data with specialized software, engineers can get a better idea of how likely a building was to be damaged following a seismic event. One key data point the systems measure using floor- and ceiling-mounted sensors is interstory drift, or how one story of a building moves in relation to another. The more interstory drift, the more likely a building is to have suffered damage.
After a major earthquake, the damage done to a structure might be obvious and visible. But it’s smaller quakes and tremors that make it much harder to know for sure. Rather than relying solely on lengthy inspections, engineers can now target their efforts on areas of a building most likely to have suffered damage, and systems like Kinemetrics’ OasisPlus make it possible. OasisPlus and similar systems can provide custom reports to building owners, analyzing data to determine the likelihood a building was actually damaged, and where the damage is most likely to have occurred.
“We empower…onsite teams to respond appropriately to the level of shaking and to see what damage is real and what isn’t,” Kinemetrics project engineer Derek Skolnik told Construction Dive. The system has so far been put to use in three hospitals in the U.S.
Another company focusing its efforts on earthquake detection and smart building monitoring is Mexico City-based Grillo. The company offers an early earthquake warning system, called Pulse, which relies on its “seismic networks” that send real-time alerts when it detects impending seismic activity, even automatically tweeting its warnings. In its 4 years in existence the company has so far deployed its sensors in buildings in Mexico and Chile.
A few factors are making this kind of detection and advance warning possible. First is the increasing ubiquity and intelligence of cloud computing, which allows collecting and processing data faster than any human is capable of. The price of sensors has also continued to fall, making it easier for public or private sector building owners to deploy them, even in the developing world.
Thomas Heaton, a civil engineer and geophysicist at California Institute of Technology in Pasadena, told Science Magazine that the ability to detect the health of structures after an earthquake has “been a dream of the engineering community for a long time.” He compares this field, dubbed structural health monitoring, to “taking a building’s blood pressure.”
A structure could seem perfectly untouched by an earthquake, but even a building showing no obvious signs of damage might not be safe. Being able to automatically evaluate structural damage allows structural engineers to inspect buildings more efficiently, and more easily identify any unseen damage following a quake. The more information owners and engineers have, the faster their buildings and occupants will be able to recover.