Structural monitoring involves the use of various equipment to collect data on the structure's performance, which is then analyzed to determine if any action needs to be taken to ensure its safety.
The type of equipment required for structural monitoring varies depending on the structure being monitored, the environmental conditions, and the data required. However, there are some essential equipment that every ideal structural monitoring system should have.
Importance of Structural Monitoring
Structural monitoring is crucial for ensuring the safety of any structure. It helps to identify any changes in the structure's behavior that may indicate a potential problem. This can help to prevent catastrophic failures that could result in injury or loss of life.
Structural monitoring also provides valuable data that can be used to optimize the design of future structures. By analyzing the behavior of existing structures, engineers can identify areas where improvements can be made to increase the safety and durability of future structures.
1. Parameters Monitored
There are various types of instruments used in monitoring the following parameters:
- Deformation, settlement
- Lateral movement, ground movements
- Tilt, inclination
- Displacement
- Stress, strain, pressure
- Load/force
2. Sensors
Sensors are the most critical component of any structural monitoring system. They are responsible for collecting data on the structure's behavior, such as vibrations, strain, temperature, and movement.
- Monitor existing buildings during restoration or for long-term monitoring:
- Tilt meter (EAN-95MW) for measurement of tilt in the X-Y axis
- Crack meter (EDJ-40V) to measure the cracks/widening of joints
- Borehole extensometer (EDS-70V) to monitor sub-surface settlement and lateral movement at different depths.
- Monitor existing buildings during nearby construction
- Tilt meters (EAN-95MW) to monitor tilt or inclination structures within the zone of influence
- Crack meter (EDJ-40V) to monitor existing cracks in structures within the zone of influence
- Prism targets (ERT-20P2) to monitor 3D movements of structures within zone of influence
- In-place inclinometer (EAN-52M) to monitor sub-surface lateral movements between construction and structure
- Piezometer (EPP-30V) for the study of pore pressure/ground water level between construction and structure
- Multipoint borehole extensometer (EDS-70V) to monitor settlement of sub-surface soil between construction and structure
- Monitor high-rise buildings during new construction
3.1. Deep excavation
- In-place inclinometer (EAN-52M) to monitor lateral deformation of sub-surface soil surrounding the excavation
- Multipoint borehole extensometer (EDS-70V) to monitor settlement of sub-surface soil surrounding the excavation
- Piezometer (EPP-30V) to monitor water pressure within and outside the excavation zone
- In-place inclinometer (EAN-52M) to monitor retaining wall inclination
- Anchor load cells (ELC-30S) to monitor stresses in the retaining structures
- Strain gauge (EDS-20V-AW) or compression load cells (ELC-210S) to monitor strut load
- Surface settlement targets (ESMP-10) to monitor ground settlement
3.2. High-rise building during construction
- Strain gage (embedment (EDS-20V-E) and arc weldable (EDS-20V-AW)) to monitor strain on structural columns
- Tilt meters (EAN-95MW) to monitor tilt
- Prism targets (ERT-10P2) to monitor 3D deformations
- Building settlement points (EBS-16) in basement levels
- Laser plummet to monitor the verticality of the structure
3. Placement of Sensors
The placement of sensors is essential for accurate data collection. Sensors should be placed in locations that are most likely to experience the highest stresses and strains, such as at the base of columns or on the surface of a bridge deck.
4. Data Acquisition System (DAS)
The data acquisition system (DAS) is responsible for collecting data from the sensors and transmitting it to the data processing and analysis software. The DAS should be designed to collect data at a high frequency to capture any changes in the structure's behavior.
5. Communication System
The communication system is responsible for transmitting data from the DAS to the data processing and analysis software. The communication system should be reliable and able to transmit data in real-time to ensure that any changes in the structure's behavior are detected promptly.
6. Data Processing and Management Software
The data processing and management software is responsible for analyzing the data collected by the sensors and the DAS. The software should be able to process large amounts of data quickly and accurately to detect any changes in the structure's behavior.
7. Power Supply System
The power supply system is responsible for providing power to the sensors, DAS, and communication system. The power supply system should be reliable and able to operate for an extended period without the need for maintenance.
8. Maintenance and Calibration
Regular maintenance and calibration of the structural monitoring system are essential to ensure accurate data collection and analysis. The sensors should be checked periodically to ensure that they are functioning correctly and calibrated to provide accurate readings.
The DAS, communication system and data processing and analysis software should also be regularly maintained to ensure that they are functioning correctly and updated with the latest software updates.
9. Cost Considerations
The cost of a structural monitoring system can vary depending on the equipment required, the structure being monitored, and the data required. However, the cost of not having a structural monitoring system can be much higher in the event of a structural failure.
When considering the cost of a structural monitoring system, it is essential to consider the long-term benefits, such as improved safety and reduced maintenance costs.
Read more: Structural Health Monitoring: Instrumentation & Monitoring During Construction
Conclusion
An ideal structural monitoring system should include sensors, a data acquisition system, a communication system, data processing and analysis software, a power supply system, and regular maintenance and calibration. By monitoring the behavior of structures over time, engineers can ensure their safety and optimize the design of future structures.
FAQs
Q1. What types of structures require structural monitoring?
Ans: Structural monitoring is required for any structure that is subject to external loads or changes in environmental conditions, such as bridges, buildings, and dams.
Q2. How often should the sensors be calibrated?
Ans: The sensors should be calibrated periodically, depending on their type and usage. Strain gauges and displacement sensors may need to be calibrated more frequently than temperature sensors or accelerometers.
Q3. Can structural monitoring systems detect potential problems before they occur?
Ans: Yes, structural monitoring systems can detect changes in a structure's behavior that may indicate a potential problem. This allows engineers to take corrective action before a catastrophic failure occurs.
Q4. How much does a structural monitoring system cost?
Ans; The cost of a structural monitoring system can vary depending on the equipment required, the structure being monitored, and the data required. It is essential to consider the long-term benefits of improved safety and reduced maintenance costs when considering the cost of a structural monitoring system.
Q5. Can a structural monitoring system be retrofitted to an existing structure?
Ans: Yes, a structural monitoring system can be retrofitted to an existing structure. However, the installation may require modifications to the structure, such as drilling holes for sensor placement. It is important to work with a qualified engineer to ensure the retrofit is performed correctly.