VW Spot-Weldable Strain Gauges

Designed to measure strain in steel, this vibrating wire strain gauge is spot-welded to the surface of the steel. A sensor is then fixed atop the gauge. Readings are obtained with a VW readout or with a data logger.

Applications

Spot-weldable strain gauges are used with strain gauge sensors and a vibrating wire indicator or data logger to monitor strain in steel members. Typical applications include:

  • Monitoring structural members of buildings and bridges during and after construction.
  • Determining load changes on ground anchors and other post-tensioned support systems.
  • Monitoring load in strutting systems for deep excavations.
  • Measuring strain in tunnel linings and supports.
  • Monitoring areas of concentrated stress in pipelines.
  • Monitoring distribution of load in pile tests.
Spot-Weldable Strain Gauges

Operation

The spot-weldable strain gauge, with its tensioned wire inside, is welded to the structural member, so that an increase in tensile strain increases tension in the wire, and a decrease in tensile strain decreases tension in the wire. A strain gauge sensor is mounted on top of the strain gauge.

On flat surfaces, the sensor is typically held in place by weld-down straps. On reinforcing and tieback bars, the sensor is often secured by cable ties and tape.

The strain gauge sensor uses an electromagnet to pluck the strain gauge and then returns a frequency signal to the readout or data logger, where it is converted to units of microstrain or period. The VW strain gauge sensor also incorporates a temperature sensor, which supplies data for temperature compensation.

Advantages

For more information

Please download the datasheet and manual for the VW Spot-Weldable Strain Gauges. These documents can be viewed and printed with Adobe Acrobat Reader.

Spot-Weldable Strain Gauges Specifications

SPOT-WELDABLE STRAIN GAUGE
Gauge Set Midrange52602100
Gauge for Compressive Strain52602101
Gauge for Tensile Strain52602102
RangeApproximately 2,500 microstrain
Gauge Length62 mm (2.45")
Height of Wire0.96 mm (0.038") above measured member
Thermal Coefficient10.8 x 10-6 per °C, 6 x 10-6 per °F
MaterialsStainless steel flange and tube, steel wire
Dimensions66.7 x 7.6 x 1.8 mm, (2.65 x 0.3 x.07 inch)
VW STRAIN GAUGE SENSOR
Strain Gauge Sensor52623000VW strain gauge sensor is a pluck-type vibrating wire sensor for spot-weldable strain gauge. Includes a thermistor or RTD for temperature measurements and two stainless steel weld-down straps for fixing the sensor to the structure. Does not include signal cable
Frequency Range0.8 to 2.4 kHz
Temp Rating-29 to 105 °C, -20 to 220 °F
Waterproof Rating10.4 bar, 150psi
MaterialsResin-filled ABS plastic case
Dimensions80 x 26 x 16 mm, 1 x 3.17 x 0.64"
Weight28 g (1 oz)
SIGNAL CABLE
Signal Cable50613824Shielded cable with four 22-gauge tinned-copper conductors and polyvinyl chloride (PVC) jacket that is rated for 80 °C (176 °F). Attached to the sensor at the factory
Universal Connector57705001
Universal Terminal Box57711600Provides connections for 12 sensors and an indicator. Sensors selected by rotary switch. Weatherproof fiberglass box measures 290 mm wide x 345 mm high x 135 mm deep (11. 5 x 13.5 x 5.25")
INSTALLATION ACCESSORIES
Scotchkote06700019For applying moisture barrier. 440 ml (15oz) can. Note that Scotchkote is flammable and may not be shipped via air freight. In addition, a hazardous materials shipping surcharge will be added to the freight cost for ground shipments
Spare Weld-Down Straps52623110Two weldable stainless steel straps designed to hold the sensor onto structure
Protective Cover52623120Formed stainless steel cover for sensor
3M Mastic Pad06700180Self-vulcanizing sealing material
Spot Welder, 115VAC52602550Includes tip, hand piece, welding unit, battery, and case
Spot Welder, 220VAC52602560Includes tip, hand piece, welding unit, battery, and case
READOUTS
Compatible readouts include the VW Data Recorder and other pluck-type VW readouts. See separate data sheets for features and specifications
DATA LOGGERS
VW MiniLogger for 1 Sensor52613310
4-Channel V-Logger52615140
8-Channel V-Logger52615180
Campbell Scientific Data LoggersVW strain gauges connect directly to the VW MiniLogger, V-Logger and Campbell Scientific CR6. Campbell Scientific CR800 or CR1000 require an AVW200 vibrating wire adapter. See separate data sheets