Structural Health Monitoring Sensors

Structural Health Monitoring Sensors Overview

When selecting a sensor, a lot of criteria need to be taken into account:

• environmental rating (temperatures, water resistance, dust resistance...),
• sensitivity,
• dynamic range,
• accuracy, and
• other criteria.

Depending on the application and customer request we can provide you with either our in-house developed or suggest you an appropriate 3rd party sensor.

Most importantly, data from any sensor, either our proprietary or 3rd party, performing static measurements or dynamic measurements are integrated into the same centralized software interface enabling automatic reporting and alarm notifications.

Supported Sensors for Dynamic Measurement

We offer several sensors for performing static measurements:

• 3-axial MEMS accelerometers
• Bolt-on strain gauges
• Microphones
• Low-noise seismic accelerometers

Crack and Joint Meters

Crack meters are sensors for monitoring displacements across joints or cracks in rock formations, dams, buildings, or bridges.

Once installed they monitor deformations caused by geotechnical activity. Depending on the application, movements can be monitored using single-axis or three-axial crack meters.

• Range: 25, 50, 100, 150, 200 mm 

• Resolution: 0.2% F.S up to 0.1% F

• Available types: Crack meter and Vibrating Wire Joint meter

IPI Inclinometers and Clinometers

IPI Inclinometers are sensors used for automated monitoring of lateral displacements to ensure the safety of infrastructure. It is essential to monitor ground stability (ground creep, slope stability, shear zone movement) during the construction works as well as over the construction life.

The installation of the inclinometer depends on the application.  Inclinometers need to be installed vertically when monitoring slope gradient in embankments or retention walls. To monitor the settlement of rocks or soil over the tunnel, horizontal installation of inclinometers is required.

• Range: ±30° (Biaxial)

• Resolution: ±0.0002° (0.004 mm/m)

• Non-linearity: ±0.002° (0.03 mm/m)

• Sensor: MEMS (Micro-Electro-Mechanical Systems) Accelerometer

• Gauge Lenght: 0.5 – 3 meters

Vibrating Wire Load Cells

Load cells are transducers used for the measurement of weight and its changes over time. They are composed of several strain gauges, to improve the sensitivity, accuracy, and reliability of the load cell. Load cells are used in the initial state during the research phase as well as at later stages, for monitoring the structure's health.

The applications for load cells include measuring and monitoring loads of ground anchors, struts, soldier piles, rock bolts, and pile load tests.

• Capacity: 445 kN to 4450 kN (100,000 to 1,000,000 lbs)

• Overrange Capacity: 150% full scale

• Sensitivity: 0.01% full scale

• Accuracy: 0.5% full scale

MEMS Accelerometers

Accelerometers are transducers used for monitoring vibrations. They produce electrical signals in proportion to acceleration.

MEMS accelerometer (Micro-Electro-Mechanical System) is actually a microchip that has a mechanical structure (a cantilever beam or seismic mass) that changes its electrical property (usually capacitance) related to the acceleration. Because of that, they are very good at measuring static and dynamic acceleration. A 3-axial accelerometer is a sensor capable of measuring acceleration in all three directions (X, Y, and Z).

IOLITE 3-axial MEMS accelerometers are used in the research phase of civil engineering projects, during construction works (especially if blasting or pile driving activities are executed) as well as at later stages, for monitoring the structure's health (for operational modal analysis). 

• Measurement range: +- 8g or +- 40g

• Bandwidth: 1.000 Hz

• Sampling speed: 4.000 S/s

• Noise density (+-2g): 25 µg/√Hz

Bolt-on Strain Gauges

Bolt-on strain gauges are transducers ideal for measuring live-load strain on all structures. They are very rugged, water and dust resistant, and build to withstand the harshest environments. They have been designed for easy installation, without the need of soldering or gluing, and are used in bridge monitoring, live-load testing, fatigue monitoring applications.

Dewesoft offers a variety of bolt-on strain gauges suitable for measuring strain in your applications.

• Strain range: 10 - 1100 μɛ

• Maximum strain: 1.500 μɛ

• Rated Output: 1.5mV/V for 1,000 micro-strain

• Linearity & Repeatability: 0.1% of rated output (FSD)

Other Supported Sensors

Our structural health monitoring system offers support also for sensors like:

• GNSS antennas for GPS positioninig
• Weather station for monitoring wind speed, wind direction, sun intensity, relative humidity, brightness
• WIM – Weigh in motion