Structural Health Monitoring Sensors
- 3-Axial ACCELEROMETERS and INCLINOMETERS: in-house developed low-noise MEMS accelerometers and inclinometers with analog-to-digital conversion, and EtherCAT interface. Ideal for permanent monitoring of structures.
- WEATHER STATIONS and GNSS antennas: monitoring wind speed, wind direction, sun intensity, precipitation, temperature, relative humidity and other weather conditions as well as accurate overall motion of structure with GNSS antennas is possible by using the Dewesoft solution.
- VIBRATING WIRE SENSORS: Dewesoft supports almost any vibrating wire sensors starting with strain gauges, piezometers, inclinometers, crack meters, extensometers and others.
- INTEGRATION SUPPORT: Dewesoft supports you with integration of any kind of sensor required in geostructural monitoring applications into a centralised software interface.
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...),
- 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 Static Measurements
We offer several sensors for performing static measurements:
- Crack and joint meters
- IPI inclinometers
- Vibrating wire strain gauges
- Vibrating wire load cells
Supported Sensors for Dynamic Measurement
We offer several sensors for performing static measurements:
- 3-axial MEMS accelerometers
- Bolt-on strain gauges
- Low-noise seismic accelerometers
Tiltmeters are used for measuring changes of inclination or vertical rotation of structures due to water level changes, ground heave, or other factors.
Dewesoft offers different tiltmeters depending on the application requirements. Our tiltmeters are MEMS-based and can be installed on a vertical or horizontal surface and can be single-axis (measuring inclination in one direction) or dual-axis (measuring inclination in two directions).
Tiltmeters are normally used for monitoring the inclination of retaining walls, foundation settlement, bridge piles, and structure health monitoring (SHM) of bridges and dams.
Resolution: from 0.001° up to 0.0006°
Available types: In-place tilt meter, tilt beam meter, submersible tilt meter, track monitoring tilt system
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
Piezometers are sensors used to monitor pore water pressure and groundwater level. They have a significant effect on ground behavior.
Piezometers are typically used for understanding drained or undrained behaviors of soil formations under loads, dewatering programs efficiency assessment, short term, and long-term soil settlement behaviors, and safety of slopes.
Over range: 25, 50, 100, 150, 200 mm
Resolution: 0.2% F.S up to 0.1% F
Accuracy: Crack meter and Vibrating Wire Joint meter
Linearity spec: <0.5% F.S.
Operating Temperature: -20 to 80°C (-4 to 176°F)
Diaphragm Displacement: <0.001 cc at F.S.
Thermal Zero Shift: <0.05% F.S./°C
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 Strain Gauges
Vibrating Wire Strain gauges are sensors capable of precise measurement of strain in different materials including concrete and steel. They are used to determine stress and its changes over time.
Vibrating Wire Strain Gauges are designed to be welded to or embedded in various structures for monitoring strain.
VW Strain gauges can be embedded or welded on any structure including high-rise buildings, dams, bridges, tunnels, nuclear plants, etc.
Strain range: 3000 μɛ
Sensitivity: 1.0 microstrain
Operating temperature: -20C to +80C
Thermal coefficient of expansion: 12.2 ppm/C
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
For temperature measurements thermistor strings are normally used sice are easy to install and reliable under demanting geotechnical conditions. Thermistor string assemblies areare available in single-point or multi-point strings..
The strings incorporate interchangeable, curve tracking, negative temperature coefficient (NTC) thermistors. As the thermistors are curve matched to desired temperature tolerance over selected temperature ranges, this permits the use of multiple sensors with a single readout or data logger, eliminating costly calibration procedures.
Interchangeability Tolerance: ±0.1°C.
Interchangeability Temp. Range: 0°C to +75°C.
Operating Temp. Range: -80°C to +75°C.
Stability: 0.01°C or better /100 months at 0°C.
Resistance at 25°: 3k ohms.
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
Low-Noise Accelerometers and Seismic Accelerometers
Low noise/Seismic accelerometers have, in comparison to MEMS accelerometers, better sensitivity and are normally used in seismic and structural monitoring projects. However, they are way more expensive compared to MEMS accelerometers.
Frequency response: 30s - 100Hz or 60 s - 100 Hz
Noise: self-noise below the USGS NLNM from 30 s to 16 Hz
High linearity: > 107 dB horizontal, 111 dB vertical
Dynamic range: over 140 dB dynamic range over a wide frequency band
Cross axis rejection over 62 dB. Sensor axes are orthogonal to within ± 0.05°
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)
Microphones are sensors that convert sound in the air into an electrical signal. They are used for noise or overpressure measurement, especially during construction works. Activities like jackhammering, pile diving, or blasting are noisy and cause concerns to neighbors. In worst-case scenarios, they lead to complaints and work suspensions.
Dewesoft offers a variety of microphones suitable for measuring and recording noise according to your application needs.
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