Vibrating wire strain gauges
The vibrating wire strain gauges are used to measure the stress in load-bearing structures or to monitor the tensions in tunnel linings, during tunnel excavation phases. Such control is necessary for the verification of the tensions and deformations of both temporary and permanent retaining structures.
The vibrating wire strain gauges consist of a stainless steel tube inside which a thin rope, secured at the two ends, is made to vibrate by an excitation coil. An internal thermistor detects the temperature. The gauge can work both in tension and compression, and is also watertight and can be installed externally in stressed structures or embedded in concrete castings for stress measurements.
Data can be read through the portable control unit or by using an automatic data acquisition system, designed to provide continuous monitoring.