Structural Health Monitoring

by Andy Slote - Dec 01 2020

All Posts Structural Health Monitoring

When structures built by humans experience issues affecting their integrity, early detection and remediation can improve safety, reduce financial impact, and increase useful life. 

Singular events like hurricanes, earthquakes, and flash floods inflict damage in the short term, triggering the need for an assessment. If a structure is still sound, ongoing monitoring is often needed to determine if non-critical issues become significant over time. 

For problems that develop more slowly due to factors like water intrusion, shifting soils, and sub-standard building materials, collecting structural health data helps determine when to take action. 

Structural Health Monitoring (SHM) is a process where gathering data contributes to an assessment of well-being for structures including: 

  • Bridges
  • Dams
  • Commercial Buildings
  • Stadiums
  • Platforms
  • Retaining Walls
  • Tunnels

Cracks in construction materials are a common issue, affecting many different types of structures. Assessing structural cracks is an excellent example of Structural Health Monitoring. Cracks often start small and remain so for long periods, potentially never becoming significant. When they are increasing in size, however, it’s crucial to track the progression. Collecting relevant data can be time-consuming and inefficient when done manually. The considerable effort required can cause delays in responses, which may increase the cost of remediation and compromise safety.  

Periodic manual inspections are useful, but installing a device that continually measures a crack’s size provides significantly more effective oversight at a lower cost. Connecting this device to a network regularly transmitting data to a well-designed application delivers the Internet of Things’ benefits. 

Let’s assume an IoT solution is monitoring a large structure with significant amounts of concrete, such as a stadium. Distributing devices throughout the stadium at key locations provides intelligence at multiple positions. There may be particular locations where the rate of increase is more significant, leading to an analysis of contributing factors. Is there an issue with soil stability, for example? If the soil issue is corrected, does this effectively reduce the rate of change? A well-constructed IoT application “dashboard” provides visibility to this kind of information.

Configuring an alert is a beneficial IoT application capability. When monitoring structural cracks, notifying someone about a potential problem when detected improves responsiveness and can lower risk. Alerts may appear on a dashboard view of the data and can be communicated via email, text message, etc., to a mobile device. Think about how useful this could be in extreme weather conditions such as hurricanes where concerns about structural integrity are more immediate!

Installing other types of sensors provides a more comprehensive view of factors affecting a structure and additional indicators of potential problems, including:

  • Temperature
  • Vibration
  • Stress
  • Materials Degradation
  • Tilt

Eventually, when we have historical data from many devices, other valuable analyses are enabled. 

What if we added our monitoring capability to multiple structures in different geographic locations built by the same contractors? What if architectural designs or construction materials differed? We now have more information to evaluate designs. Ideally, all of this information will help make us better decisions for future projects.

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