PRECISION GEOTECHNICAL MONITORING

English (United Kingdom)Slovenčina (Slovenská republika)
Tuesday, 15 October 2019
Measurements of strain in constructions

Purpose: Vibratory (string) strain gauges are sensors with high precision by which it is possible to derive indirectly from the relative deformation of steel or concrete structures the stress in the civil, industrial, hydraulic and transport buildings (high-rise buildings, bridges, piles, tunnel linings, etc.). In the monitoring of the buildings we use the following strain gauges of company Geokon: VSM-4000 strain gauges, VK-4100 (stress in steel structures), VCE-4200, VCE-4210 (stress in the concrete structures).

Description of the system: The tensometers (strain gauges) are composed of two parts: of a steel wire stretched between the two mounting-blocks and of the measuring excitation coil. The mounting -blocks can be attached to the monitored construction of by welding, bonding or lashing to the stiffening. The deformations of the structure shall cause mutual displacement of the blocks of the tensometer, changing the length or tension of the steel wire, which is measured as its own frequency of vibration after excitation. The reading units send out the excitation impulse for vibration of wire and transfer the resulting vibrations directly to the microstrains. The gauges are supplied with a built-in thermistor for temperature measurement in the place of the sensor instalment. The readings of the gauges are possible using a portable reading units, or automatically at set intervals by data-loggers. For the evaluation of the measurements in units of voltage it is necessary to know the deformation modulus of building material.

Specifications:
GAGE TYPE:

Active gage length

Standard range

Resolution

Temperature rang
VSM-4000

150 mm

3000 με

1,0

-20 ÷ +80°C
VK-4100

57 mm

2500 με

0,5

-40 ÷ +120°C
VCE-4200

153 mm

3000 με

1,0

-20 ÷ +80°C
VCE-4210 
 
250 mm

3000 με

0,5

-20 ÷ +80°C

 tenzometer_1Vibrating wire strain gage – model 4000 (for steel) and 4200 (for concrete) tenzometer_2Vibrating wire strain gage – model 4100Inštalácia tenzometra na VTL plynovod Strain gage installation at the high-pressure gas pipeline

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