Vibrating Wire Strain Gauges

The G1-BVC vibrating wire strain gauges by Tecnopenta are measuring instruments designed for deformation monitoring and stress condition control of structural elements in steel and concrete.

Thanks to vibrating wire technology, they provide high sensitivity, accuracy and long-term measurement stability, making them particularly suitable for structural and geotechnical monitoring applications, both temporary and permanent.

The G1-BVC strain gauges are available in two versions: weldable, for installation on metallic elements, and embedment, for integration within concrete structures.

Both versions allow deformation to be measured in both tension and compression and include a temperature sensor for evaluating thermal effects on measurements.

Operating principle

The operation of the G1-BVC strain gauges is based on vibrating wire technology.

A metal wire, maintained under tension inside a stainless steel body, changes its natural vibration frequency according to the deformation transmitted by the structure on which it is installed.

The frequency is detected by an electromagnetic coil and used to determine the deformation of the monitored element.

The integrated NTC thermistor also measures the temperature near the sensor, providing a useful parameter for evaluating the influence of thermal variations.

This technology is particularly suitable for long-term monitoring systems, thanks to the possibility of transmitting the signal over long distances.

Main applications

The G1-BVC vibrating wire strain gauges are used in numerous civil, structural and geotechnical engineering applications:

• Tunnels and underground works: monitoring deformation of steel ribs and structural linings.
• Steel structures: deformation control of metallic elements subjected to loads and stresses.
• Concrete structures: monitoring internal deformation of structural elements.
• Foundation piles and load tests: deformation measurement during load application.
• Diaphragm walls and foundations: deformation control of retaining elements and underground structures.
• Bridges, viaducts and infrastructure: structural monitoring during operation.
• Dams and hydraulic works: deformation control of structural elements.
• Port structures: monitoring deformation of works subjected to mechanical stresses.

Features and advantages

• Vibrating wire measurement technology.
• Measurement of tensile and compressive deformation.
• High sensitivity and accuracy.
• Robust stainless steel body.
• IP68 protection rating.
• Integrated temperature sensor.
• Suitable for long-term structural monitoring.
• Overvoltage protection.
• Signal transmission over long distances.
• Compatible with manual reading units and automatic acquisition systems.
• Available in weldable and concrete embedment versions.

Weldable version

The G1-BVC weldable version is designed for monitoring deformation in metallic structures.

The sensor is fixed by welding to the element to be monitored, allowing structural deformation to be transferred to the internal vibrating wire.

It is particularly suitable for steel ribs, structural steel elements and retaining structures.

Embedment version

The G1-BVC embedment version is designed to be directly embedded within concrete.

It allows internal deformation of structural elements to be measured and is suitable for foundations, piles, diaphragm walls, beams, columns and other concrete structures.

Technical specifications

Weldable version

• Installation type: welding on structure
• Wire length: 153 mm
• Measurement range: 3,000 µε
• Sensitivity: 1 µε
• Total accuracy: less than 0.5% F.S.
• Typical frequency: 800 Hz
• Temperature sensor: NTC thermistor 3 kΩ
• Coil resistance: 150 Ω
• Operating temperature: from -20 to +80 °C
• Dimensions: 165 × 25 × 25 mm
• Material: stainless steel
• Protection rating: IP68

Embedment version

• Installation type: embedment in concrete
• Wire length: 145 mm
• Measurement range: 3,000 µε
• Sensitivity: 1 µε
• Total accuracy: less than 0.5% F.S.
• Typical frequency: 900 Hz
• Temperature sensor: NTC thermistor 3 kΩ
• Coil resistance: 150 Ω
• Operating temperature: from -20 to +80 °C
• Dimensions: 175 × 25 × 25 mm
• Material: stainless steel
• Protection rating: IP68

Data acquisition and monitoring systems

The G1-BVC strain gauges can be used both for periodic measurements with portable readout units and within automatic continuous monitoring systems.

Compatibility with automatic acquisition systems allows the sensors to be integrated into structural and geotechnical monitoring networks for the collection and analysis of deformation over time.