After an earthquake has occurred, it is critical for engineers and other experts to assess a building’s damage status and structural integrity. This is a process that can start from a few days and take much longer, depending on the severity of the earthquake. Of course, it can also be a frustrating process for building occupants displaced due to post-earthquake safety assessment.
But are there any methods that will enable us to get through this process more easily? The answer is yes, in its simplest form. So, what are the new technologies that make it faster and easier to detect damage after an earthquake? And what are the methods?
Pasadena-based Kinemetrics, a company specializing in earthquake and building monitoring technology, offers sensor-based systems installed throughout a building that collect and transmit seismic data, measuring the intensity, duration, and more of an earthquake.
How do sensors work in damage detection?
By processing this data from the sensors with special software powered by artificial intelligence, engineers can get a better idea of the probability of a building being damaged after a seismic event. One of the key data points the systems measure using floor- and ceiling-mounted sensors is inter-floor slip, or how one floor of a building moves relative to another. The greater the slip between floors, the higher the probability that a building has been damaged.
After a major earthquake, the damage to a structure can be clearly visible. However, it is much more difficult to know the exact damage, especially after small earthquakes and tremors (or at the outer boundaries of the earthquake affected area). With systems like Kinometrics’ OasisPlus, engineers can focus their efforts on the areas of a building that are most likely to be damaged, rather than relying solely on lengthy inspections. OasisPlus and similar systems can provide building owners with tailored reports and analyze data to determine the probability that a building has actually been damaged and where the damage is most likely to occur.
“We empower field teams to respond appropriately to the shaking level and see what damage is real and what isn’t,” Kinemetrics project engineer Derek Skolnik told Construction Dive. The system has been used in three hospitals in the USA so far.
Advantages of sensor systems in damage detection
Mexico City-based Grillo is another company focusing its efforts on earthquake detection and smart building monitoring. The company offers an early earthquake warning system called Pulse, which is based on “seismic networks” that send real-time alerts when it detects imminent seismic activity, or even tweet its alerts automatically. During its 4 years of existence, the company has so far installed its sensors in many buildings in Mexico and Chile.
There are several factors that make this type of detection and forewarning possible. The first is the ubiquity of cloud computing and the rise of the intelligent system, which allows for faster data collection and processing than any human can do. Sensor prices also continue to fall, making it easier for public or private building owners to deploy sensors, even in developing countries.
Thomas Heaton, a civil engineer and geophysicist at the California Institute of Technology in Pasadena, told Science Magazine that the ability to detect the health of structures after an earthquake has “long been a dream of the engineering community.” He says this field, called structural health monitoring, is like “measuring the blood pressure of a building.”
A structure may appear to have never been affected by an earthquake. But even a building that shows no obvious signs of damage may not be safe. Being able to automatically assess structural damage allows structural engineers to more efficiently inspect buildings and more easily detect unseen damage following an earthquake. The more information building owners and engineers have, the faster they can alert buildings and residents.
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