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Geotechnical load cells BA-EST/CV

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The BA-EST / CV vibrating string extensometer bars are used to measure the existing tension states in load-bearing structures or to monitor
the tensions existing in the ribs during tunnel excavation. This control is necessary for checking the tensions and deformations of both
temporary and permanent support structures.

The vibrating string strain bars consist of a stainless steel tube inside which a thin rope, fixed at both ends, is vibrated by an excitation coil. An
internal thermistor also measures the temperature. The BA-EST / CV strain gauge rod can work either tensile or compressive, and the
sensitized part is resin-coated in order to preserve the functionality of the instrument in case of impact or immersion.

Data can be read out by using the portable control unit or by an automatic data acquisition system, designed to carry out continuous
monitoring. The bar is watertight, can be applied externally to stressed structures or drowned in concrete castings for stress measurements

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Geotechnical load cells BA-EST/CV

Technical Specifications

MaterialStainless steel
Measuring range3000 μ ɛ
Sensitivity1 μ ɛ
Operating temperature-20 / +80C (-4 / +176F)
Protection classIP 68
Sensor typevibrating string
Total accuracy< 0.5% of full scale
Internal thermistorNTC 3 kΩ
Cord length153 mm (welding), 145 mm (concrete)
Type of installationWelding on metal, sinking in concrete
Typical frequency800 Hz
Resistance of the spool150 Ω
Dimensions welding bar165 x 25 x 25 mm (6.49 x 0.98 x 0.98 in.)
Dimension concrete bar157 x 25 x 25 mm (6.18 x 0.98 x 0.98 in)
Standard cable length3 m 4 x 0,25 (shield not connected to the load cell body)
For the complete and latest technical specifications, please refer to the technical data sheet which can be downloaded here:
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General precautions to be followed in the installation and assembly of load cells:

  • Follow the direction of application of force on the load cell
  • Do not exceed the limits of the temperature as indicated in the data sheet
  • Do not remove labels from the load cell
  • Adequately protect the cables with sleeves or channels
  • Carry out on each load cell a ground connection with suitable cable, shunt on mounting accessories
  • Do not carry out any welding on the mechanical structure after mounting the load cell
  • Avoid or reduce to a minimum level any mechanical constraints between the rigid structure and the weighing structure to avoid error in weighing and return to zero
  • In case of vibration or dynamic loads product the load cells with puffers / shock absorbers
  • Protect load cell from any dust accumulation with any appropriate means