VW Embedment Strain Gauge
VW embedment strain gauges are used to measure strain in reinforced concrete and mass concrete.
The strain gauge operates on the principle that a tensioned wire, when plucked, vibrates at a frequency that is proportional to the strain in the wire. The gauge is constructed so that a wire is held in tension between two end flanges. Loading of the concrete structure changes the distance between the two flanges and results in a change in the tension of the wire. An electromagnet is used to pluck the wire and measure the frequency of vibration. Strain is then calculated by applying calibration factors to the frequency measurement.
In reinforced or pre-stressed concrete applications, the embedment strain gauge is usually tied to the reinforcing cage. In mass concrete applications, the gauge may be installed either before or immediately after placement of the concrete. Gauges may be configured in a rosette either by direct placement in the soft concrete or by attachment to a rosette adapter.
Permanently Attached Coils: The coils used to excite and read the vibrating wire cannot be accidentally separated from the body during installation and wiring operations.
Built-in Temperature Sensor: The temperature sensor is useful for temperature corrections when the gauge is installed on materials that have a different temperature coefficient.
Reliable Signal Transmission: The arc-weldable strain gauge provides a strong signal which can be transmitted reliably over long distances with properly shielded cable.
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