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Vibrating Wire Embedment
Strain Gauge (VWSG-E)
Installation and User Manual
All efforts have been made to ensure the
RST Instruments LTD.
accuracy and completeness of the information
11545 Kingston St.,
contained in this document. RST Instruments Ltd.
Maple Ridge, BC
reserves the right to change the information at
Canada V2X 0Z5
any time and assumes no liability for its accuracy.
SALES + SERVICE +MANUFACTURING
Copyright © 2022. RST Instruments Ltd. All rights
reserved.
604-540-1100
|
info@rstinstruments.com
Document Number: ELM0085D
Toll Free (USA & Canada) 1-800-665-5599
Release Date: 02 April 2025
www.rstinstruments.com
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Related Manuals for RST Instruments VWSG-E
Summary of Contents for RST Instruments VWSG-E
- Page 1 Maple Ridge, BC reserves the right to change the information at Canada V2X 0Z5 any time and assumes no liability for its accuracy. SALES + SERVICE +MANUFACTURING Copyright © 2022. RST Instruments Ltd. All rights reserved. 604-540-1100 info@rstinstruments.com Document Number: ELM0085D Toll Free (USA &...
- Page 2 Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual EVISION ISTORY Rev. Revision History Date Prepared By Approved By Initial release. 2017-Dec-04 Updated references to other manuals, updated formatting, updated equation reference on p. 13 2019-Sep-23 to “Using Equation 6” (previously 10), added list of tables, added specification table.
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Page 3: Table Of Contents
Notes on Vibrating Wire Readout Units .............. 1 ..................2 NSTALLATION INTO ONCRETE VWSG-E Strain Gauge for Concrete Embedment ..........2 VWSG-E Strain Gauge Attachment ..............3 2.2.1 Direct Attachment to Rebar with Blocking ..........3 2.2.2 Suspended Attachment to Rebar Mat ............3 Using Pre-cast Briquettes or Grouting ............... - Page 4 Equation 7 True Load Related Strain Calculation ..............12 Equation 8 Convert Thermistor Resistance to Temperature ............15 IST OF IGURES Figure 1 Attaching VWSG-E Strain Gauges to Rebar ..............4 Figure 2 Lighting Protection Scheme ..................6 IST OF ABLES Table 1 Sweep Frequencies .......................
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Page 5: Introduction
Installation and User Manual NTRODUCTION RST VWSG-E Vibrating Wire Strain Gauges are designed for the measurement of strains in Civil and Structural Engineering. VWSG-E Type Strain Gauges may be directly embedded within mass concrete. Stress changes within these materials can then be calculated, based on the strain measurement changes, if the modulus of the material is known. -
Page 6: Notes On Vibrating Wire Readout Units
Strain Gauge Calibration Record Sheet for the instrument to be read, in order to confirm these requirements. In general, VWSG-E Vibrating Wire Strain Gauge instruments use a sweep frequency of 450 to 1200 Hz. However, the operator must always refer to the VW Calibration Record Sheet for the VWSG-E Strain Gauge sensor to be read, in order to determine the correct sweep frequency required to obtain a correct reading. -
Page 7: Installation Into Concrete
No adjustment of the initial wire tension is possible by the User, without specialized equipment and instructions. VWSG-E Strain Gauges are normally installed into concrete pours by tying the Strain Gauges to adjacent reinforcing bar or alternatively casting the Strain Gauges into briquettes, which are subsequently tied to a reinforcing bar. -
Page 8: Vwsg-E Strain Gauge Attachment
VWSG-E S TRAIN AUGE TTACHMENT The following directions are provided for attaching model VWSG-E Strain Gauges within a rebar cage. 2.2.1 Direct Attachment to Rebar with Blocking 1. Wrap a layer of self-vulcanizing rubber tape around the Strain Gauge at the two locations where the gauge will be mounted to the rebar (refer to Figure 2). -
Page 9: Using Pre-Cast Briquettes Or Grouting
Installation and User Manual 5. Tighten the wire by twisting on the loops and orient the Strain Gauge. 6. Tie the instrument cable off to a nearby rebar using nylon Ty-Raps. Figure 2: Attaching VWSG-E Strain Gauges to Rebar SING CAST... -
Page 10: Lightning Protection
IGHTNING ROTECTION VWSG-E Vibrating Wire Strain Gauges, unlike numerous other types of Vibrating Wire instruments available from RST, do not have any integral lightning protection components included. Integral surge protection devices are normally not required because the installation environment, which is usually well grounded, provides adequate protection. -
Page 11: General Installation Guidelines
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual Figure 3: Lightning Protection Scheme ENERAL NSTALLATION UIDELINES For every Strain Gauge installation, the installer needs to identify the key construction sequence events and the key instrument installation steps that will occur at the site. A successful installation must consider both interdependent activities in detail. -
Page 12: Taking Readings With Vw2106 Readout Unit
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual 8. Following installation of first rebar cage into the excavation 9. Following splicing of second rebar cage onto the first rebar cage 10. Following installation of second rebar cage into the excavation 11. -
Page 13: Operation Of The Vw2106 Vw Readout Box
3. The operator must refer to the VW Calibration Record sheet for the VWSG-E Strain Gauge sensor which is to be read in order to determine correct sweep frequency to use to obtain a correct reading. -
Page 14: Initial Readings
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual Refer to the table below indicating the various sweep frequencies provided by the RST VW2106 VW Readout Box for reading VW sensors. Note the following Sweep Frequencies used for reading Strain Gauge instruments: C Sweep –... -
Page 15: Data Interpretation
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual NTERPRETATION ONVERSION OF EADINGS TO HEORETICAL ICROSTRAIN The VW2106 Vibrating Wire Readout unit provides B Unit readings which are related to the resonant vibration frequency of the Vibrating Wire sensor. This relationship to reading frequency is provided in the following equation. -
Page 16: Conversion Of Readings To Strain Changes
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual Example Calculation – Change in Strain NOTE: The values used in this example calculation are for explanation purposes only. Please refer to the provided Calibration Sheet for actual values. - For a Model VWSG-A Arc Weldable Strain Gauge - VW Readings taken using Sweep C at 450 to 1200 Hz ... -
Page 17: Strain Resolution
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual Note: – R When (R ) is positive The strain is TENSILE – R When (R ) is negative The strain is COMPRESSIVE TRAIN ESOLUTION The VW2106 Vibrating Wire Readout unit provides B Unit readings with a resolution of 0.1 B Units. -
Page 18: Temperature Corrections
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual EMPERATURE ORRECTIONS Temperature variations of considerable magnitude are not uncommon in concrete, particularly during the curing period with may take up to several weeks, or longer. Therefore, it is always advisable to measure and record temperature along with every Strain Gauge measurement. -
Page 19: Shrinkage Effects
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual Using Equation 6-6: Apparent Strain = (2900 - 3000 ) x 0.975 = -100 x 0.975 = - 97.5 (compression) Temperature Related Strain = ... -
Page 20: Troubleshooting
Incorrect excitation sweep frequency used. Check sweep frequency recommended on the VW Calibration Record sheet. • For VWSG-E the Strain Gauges should be pre-installation tested on a solid surface, otherwise the entire gauge may oscillate, causing erroneous and unstable output values. -
Page 21: Service & Repair
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual ERVICE EPAIR ONTACT NFORMATION This product does not contain any user-serviceable parts. Contact RST for product services or repairs. • For sales information: sales@rstinstruments.com • For technical support: support@rstinstruments.com •... -
Page 22: Thermistor Temperature Derivation
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual HERMISTOR EMPERATURE ERIVATION Thermistor Type: YSI 44005, Dale 41C3001-B3, Alpha #13A3001-B3 Resistance to Temperature Equation: QUATION ONVERT HERMISTOR ESISTANCE TO EMPERATURE - 273.2 A + B(LnR) + C(LnR) where: Temperature in °C. - Page 23 Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual ABLE HERMISTOR ESISTANCE VERSUS EMPERATURE Ohms Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp 201.1K 16.60K 2417 525.4 153.2 +110 187.3K 15.72K 2317 507.8 149.0 174.5K 14.90K 2221 490.9 145.0...
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Page 24: Vw Embedment Train Auge Pecifications
Vibrating Wire Embedment Strain Gauge (VWSG-E) Installation and User Manual VW E MBEDMENT TRAIN AUGE PECIFICATIONS ABLE PECIFICATIONS Specification Value 3000 με Range 1.0 με Resolution Accuracy Batch Calibration: ±0.5%FS Individual Calibration: ±0.1%FS Using curve fitting techniques (second order polynomial Linearity 0.5%FS...
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