Structural Health Monitoring of Veterans Affairs’ Hospital Buildings
In collaboration with the U.S. Department of Veterans Affairs (VA), the National Strong Motion Project of the U.S. Geological Survey has been installing sophisticated seismic systems that will monitor the structural integrity of 29 VA hospital buildings located in conterminous United States, Alaska and Puerto Rico during earthquake shaking. These monitoring systems, which combine sensitive accelerometers and real-time computer calculations, are capable of determining the structural health of each instrumented structure rapidly after an event, helping to ensure the safety of patients and staff.
Click on an orange circle on the map to see details at each instrumented structure.
Assessing a Building’s Structural Health and Detecting Damage
Flow chart showing the functioning of a real-time earthquake monitoring system for instrumented buildings. The system provides important information on the structural health of the building. After a significant earthquake, its near-real-time data analysis capabilities help to rapidly assess building safety.
After a major earthquake it is imperative to monitor the condition of hospital buildings in near-real time in order to be able to assess their structural integrity immediately. Structural health monitoring is achieved by the array of sensors in the building and an open-source on-site data analysis system called USGS OpenSHM. This innovative system provides information about how buildings move and distort during shaking and where possible damage likely occurred. Several independent algorithms check for variations in movements of a building frame and its vibration characteristics, for travel time of seismic waves between foundation and roof, and for exceedance of the building’s seismic design capacity. If the damage detection algorithms agree, alarm messages are sent.
This information allows rapid assessment of building safety in the aftermath of a major quake and supports decisions about necessary repairs, replacements, and other maintenance and rehabilitation measures. In the long run, this system also monitors the building’s structural components for indications of deterioration and fatigue, enabling the building to be made more resilient and sustainable through improved maintenance. Recordings from structural-health monitoring systems are critical to designing safer hospitals and other buildings and to preventing loss of life. In particular they will help engineers to:
- assess building safety immediately following a damaging quake,
- understand how damage to structural and nonstructural components (such as equipment and pipes) occurs from strong shaking,
- evaluate and improve earthquake-resistant design techniques and also methods for predicting the seismic performance of structures, and
- improve earthquake-resistant design provisions of building codes.
These efforts in turn will help the U.S. Department of Veterans Affairs safeguard its building inventory from future earthquake losses.
Fact Sheets
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Helping Safeguard Veterans Affairs’ Hospital Buildings by Advanced Earthquake Monitoring
USGS Fact Sheet 2012–3094, by Erol Kalkan, Krishna Banga, Hasan S. Ulusoy, Jon Peter B. Fletcher, William S. Leith, and James L. Blair
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Real-Time Seismic Monitoring of Instrumented Hospital Buildings
USGS Fact Sheet 2012–3028, by Erol Kalkan, Jon Peter B. Fletcher, William S. Leith, Jill McCarthy, and Krishna Banga
