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Geotechnical Instrumentation |
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The resonant frequency of vibration of a tensioned steel wire is proportional to the strain or tension in that wire. This fundamental relationship is utilised in a variety of configurations for the measurement of strain, load, force, pressure, temperature and tilt. The advantages of vibrating wire sensors over more conventional types lies mainly in their long-term stability and the sensor output which is frequency rather than voltage. Frequencies can be transmitted over long (>2000m) cables without noticeable degradation of the signal caused by variations in cable resistance which can arise from water penetration, temperature fluctuations, contact resistance or leakage to ground. This factor, coupled with the sophistication and ruggedness of the design results in sensors which exhibit excellent durability and which are ideally suited for long-term measurements in adverse environments.
Instruments supplied by Strainstall are used primarily for monitoring the safety and stability of civil structures such as tunnels, foundations, piles, embankments, retaining walls, slopes, subway systems, bridges, pipelines, shafts, groundwater remediation schemes and the like, and include: |
  
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- Dataloggers (Single & Multi Channel)
Easy to use dataloggers for all types of vibrating wire sensors and their internal temperature sensors.
- Pieszometers
Designed to measure fluid pressures such as ground water elevations and pore pressures when buried directly in embankments, fills etc
- Inclinometers (In Place & Portable)
Used for the remote, continuous and automatic monitoring of the stability of slurry walls, sheet piling and tie-back walls around excavations, lateral ground movements and differential settlements in, around and above tunnels and underground openings.
- Load Cells
Vibrating load cells are used to monitor long-term loads in concrete dam tie-downs, loads in steel arch tunnel supports and for the measurement of loads during pile testing.
- Strain Gauges (Weldable & Embedment)
Designed primarily for long-term strain measurements of steel structures such as tunnel linings, excavation bracing, piles and bridges.
- Extensometers
Extensometers measure displacement or deformation in soil, rock and concrete structures. Typical applications include measurement of ground movements and tunnels, subsidence above tunnels and mine openings and settlement and heave of foundations in soft soil.
- Tiltmeters
Designed for attachment to structures, on either a vertical or horizontal surface by means of an adjustable bracket, and for the subsequent measurement of any tilting that may occur.
- Crackmeters
Crackmeters are designed to measure movement across joints such as construction joints in buildings, bridges, pipelines etc, tension cracks and joints in rock and concrete.
- Pressure Cells
The Jackout Pressure Cell is designed for installation in diaphragm walls (slurry walls) to monitor soil pressures on walls and excavation proceeds. This allows the build-up of excessive pressure to be detected in time to take remedial measures.
- Sister Bars
Sister bars are designed to be embedded in concrete for the purpose of measuring concrete strains due to imposed loads.
- Convergence Meters
Designed to detect deformation in tunnels and underground taverns by measuring the contraction or elongation between two anchor points fixed in walls of the tunnel or cavern.
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Strainstall Middle East LLC,
Member of James Fisher & Sons plc
PO Box 111007, Plot# 599-1254, Jebel Ali Industrial Area #1, Dubai, United Arab Emirates
Tel: 00971 4 880 4380 · Fax: 00971 880 4381 · Email: info@strainstall.ae
© 2006 Strainstall Middle East LLC, All Rights Reserved
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