Vibrating Wire Strain Gauge - Embedment
Strain gauges offer the ability to measure the effect of loads, settlement or other changes in a structure. They record strain, which is a dimensionless measure of deformation. Stress is related to strain by a material’s properties and is predictable within a certain range of applied strain.
Strain gauges are useful for determining the effects of applied loads to a structure, such as the loading of post tension cables or removal of temporary supports. Piles of driven, cast or pre cast construction can also benefit from strain measurement as with sufficient strain gauges information such as the depth at which the load is transferred to the soil and the percentage of the load born as end bearing can be determined.
Geosense® VWS-2100 series vibrating wire [VW] embedment strain gauges are designed for direct embedment in concrete.
Features
- Reliable long term performance
- Rugged, suitable for demanding environments
- High accuracy
- Insensitive to long cable lengths
- Totally waterproof
- Direct embedment in concrete
- Auto resonant units available
Applications
Measurement of stress and strain deformation in:
- Driven and bored piles
- Tunnels and deep excavations
- Mass concrete pours
- Pre-cast piles
- Concrete dams
- Retaining walls
- Dynamic measurements w. auto resonant version
- Building foundations
Specifications
- VWS-2100 vibrating wire strain gauges may be read by the VW-2106 or any vibrating wire readout device and may be readily connected using any datalogger with vibrating wire interface modules.
- Vibrating wire strain gauges output a frequency signal and are therefore insensitive to resistance changes in connecting cables caused by contact resistance or leakage to ground.
- Cable may be readily and simply extended on site without special precautions. Gauges may be read up to 1000 metres away from their installed location without change in calibration.
- VWS-2100 strain gauges are fully waterproof all stainless steel construction with coils encapsulated with epoxy resin. The protective tube assembly is totally sealed to the embedment flanges by laser welding, eliminating any possibility of seal degradation. During the testing and stressing procedures welds are fully checked by tensile testing carried out in excess of the elastic limit of the protective tube assembly.
- Strain gauge rosettes and zero strain containers are available for VWS-2100 gauge series. VWS-2125 can be used within mass concrete with coarse aggregates as heavy duty construction resists bending and the large end flanges provide a high contact area.
Model Number | VW S-2100 | VW S-2120 | VW S-2125 |
Gauge length | 150 mm | 50 mm | 250 mm |
Overall length | 156 mm | 54 mm | 260 mm |
Resolution | 1 με | 1 με | 1 με |
Strain range | 3000 με | 3000 με | 3000 με |
Accuracy1 | ±0.1% to ±0.5% FS | ±0.1% to ±0.5% FS | ±0.1% to ±0.5% FS |
Non linearity | <0.5% FS | <0.5% FS | <0.5% FS |
Temperature range | -20°C to +80°C | -20°C to +80°C | -20°C to +80°C |
Frequency range | 850 - 1550 | 1500 - 3500 | 1500 - 3500 |
Readout and Datalogger Systems
Custom datalogger systems for any number of sensors in any configuration are also available and can be designed on request. Please see our other webpage for details of readout equipment, terminal boxes and data loggers specific to vibrating wire devices.