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Summary of Contents for Geokon 4000 Series
- Page 1 Model 4000 Series (4050 included) Vibrating Wire Strain Gauges Instruction Manual ©2018, GEOKON. All rights reserved. Document Revision: DD | Release date: 12/6/18...
- Page 3 WARRANTY STATEMENT warrants its products to be free of defects in materials and workmanship, GEOKON under normal use and service for a period of 13 months from date of purchase. If the unit should malfunction, it must be returned to the factory for evaluation, freight prepaid.
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Page 5: Table Of Contents
3.4 INSTALLING ON CONCRETE SURFACES USING ANCHOR STUDS ..3.5 SETTING THE STRAIN GAUGE ....................4. GAUGE PROTECTION ..........................4.1 PROTECTION FROM MECHANICAL DAMAGE USING GEOKON MODEL 4000-6 ............................4.2 PROTECTION FROM DIRECT SUNLIGHT AND RAPID CHANGES IN AMBIENT TEMPERATURE ...................... - Page 6 6.4.1 CONNECTING SENSORS WITH 10-PIN BULKHEAD CONNECTORS ATTACHED ............................6.4.2 CONNECTING SENSORS WITH BARE LEADS ..............6.4.3 OPERATING THE GK-403 ......................6.5 MEASURING TEMPERATURES .................... 7. DATA REDUCTION ..........................7.1 CONVERSION OF THE READINGS TO STRAIN CHANGES ......7.2 CONVERTING STRAINS TO STRESSES ...............
- Page 7 FIGURES FIGURE 1: MODEL 4000 VIBRATING WIRE STRAIN GAUGE .........1 FIGURE 2: SPACING JIG ....................3 FIGURE 3: WELDING SEQUENCE FOR THE MOUNTING BLOCKS ........3 FIGURE 4: PROTECTION ON DRIVEN PILES ..............4 FIGURE 5: INSTALLATION USING EPOXY ...............5 FIGURE 6: INSTALLATION ON CONCRETE USING GROUTABLE ANCHORS ....6 FIGURE 7: COVER PLATE INSTALLATION, TOP VIEW ............8 FIGURE 8: COVER PLATE INSTALLATION, SIDE VIEW ...........8 FIGURE 9: LIGHTNING PROTECTION SCHEME .............10...
- Page 8 TABLES TABLE 1: STRAIN GAUGE READOUT POSITIONS............15 TABLE 2: SAMPLE RESISTANCE ..................21 TABLE 3: RESISTANCE WORK SHEET ................21 TABLE 4: SPECIFICATIONS ....................23 TABLE 5: THERMISTOR RESISTANCE VERSUS TEMPERATURE ........26...
- Page 9 EQUATIONS EQUATION 1: AXIAL STRESS CALCULATION ..............12 EQUATION 2: STRESS DUE TO BENDING ON AXIS YY ..........12 EQUATION 3: STRESS DUE TO BENDING ON AXIS XX..........12 EQUATION 4: MAXIMUM STRESS .................. 12 EQUATION 5: THEORETICAL MICROSTRAIN ..............19 EQUATION 6: STRAIN CALCULATION................
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Page 11: Introduction
This manual contains installation instructions, readout instructions, recommended maintenance, and troubleshooting procedures. The theory of the gauge is also given, along with some suggestions for data interpretation. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | INTRODUCTION | 1... -
Page 12: Preliminary Checks
Resistance between thermistor leads (usually green and white) will vary based on temperature; see Table 5 on page 26. Resistance between any conductor and the shield should exceed two megohms. Should any of these preliminary tests fail, see Section 8 for troubleshooting tips. 2 | PRELIMINARY CHECKS | GEOKON... -
Page 13: Gauge Installation
Weld the edges of the mounting blocks in the order shown in the following figure. Weld FIGURE 3: Welding Sequence for the Mounting Blocks MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE INSTALLATION | 3... -
Page 14: Installation On Driven Steel Piles
Cables must be restrained by welding studs at three-meter intervals, to which the cables can then be tied. Channel Iron Angle Iron Welded Stud Window for Gauge Install 4000 Gauge Mounting Block Weld End View FIGURE 4: Protection on Driven Piles 4 | GAUGE INSTALLATION | GEOKON... -
Page 15: Installation Using Epoxy Cements
(see the figure below). Bottom View Loctite 410 Instant Adhesive Spacer bar Devcon Underwater Putty on two thirds FIGURE 5: Installation Using Epoxy MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE INSTALLATION | 5... -
Page 16: Steel Surfaces
Once the grout has cured, continue with the installation by proceeding to Section 3.5. Groutable Anchors (Product 4000-5) Grout or Epoxy Setting Distance 5.875 inches / 149 mm FIGURE 6: Installation on Concrete Using Groutable Anchors 6 | GAUGE INSTALLATION | GEOKON... -
Page 17: Setting The Strain Gauge
Celsius. An GEOKON ohmmeter can also be used. (The relationship between resistance and temperature is shown in Appendix C.) MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE INSTALLATION | 7... -
Page 18: Gauge Protection
GAUGE PROTECTION 4.1 PROTECTION FROM MECHANICAL DAMAGE USING GEOKON MODEL 4000-6 Special cover plates made from sheet steel formed into a channel shape are available from . Use the mounting hardware provided to install the cover GEOKON plates as follows: Weld the two 9.5 x 51 mm (3/8 x 2") long hex bolts in place head down. -
Page 19: Protection From Direct Sunlight And Rapid Changes In Ambient Temperature
Unlike numerous other types of instrumentation available from GEOKON vibrating wire strain gauges do not have any integral lightning protection components, such as transorbs or plasma surge arrestors. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE PROTECTION | 9... -
Page 20: Figure 9: Lightning Protection Scheme
Consult the factory for additional information on available lightning protection. Steel Beam Terminal Box or Multiplexer Gauge 4000 Lab3 Copper Ground Wire Enclosure Instrument Cable (usually buried) Ground Connections FIGURE 9: Lightning Protection Scheme 10 | GAUGE PROTECTION | GEOKON... -
Page 21: Gauge Location
(see Appendix H). Consider the example of an I-beam, as shown in the figure below. AXIS XX AXIS YY FIGURE 10: Strain Gauges Mounted on Central Web MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE LOCATION | 11... -
Page 22: Equation 1: Axial Stress Calculation
It is also not uncommon for local blocking (e.g., tunnel arch supports) and the addition of struts, to cause strain changes on a single nearby gauge. 12 | GAUGE LOCATION | GEOKON... -
Page 23: Figure 11: Strain Gauges Mounted On Flanges
Another possible two-gauge configuration is shown in Figure 13 on page 14. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | GAUGE LOCATION | 13... -
Page 24: Figure 13: Axial Strain And Bending Moments About Xx Axis
This configuration is not recommended. AXIS XX AXIS YY FIGURE 14: Axial Strain and Bending Moment About Axis XX (NOT RECOMMENDED) 14 | GAUGE LOCATION | GEOKON... -
Page 25: Taking Readings
20 hours continuously on two AA batteries. It is designed for the readout of all vibrating wire instruments, GEOKON and is capable of displaying the reading in either digits, frequency (Hz), period (s), or microstrain (). The GK-404 also displays the temperature of the transducer (embedded thermistor) with a resolution of 0.1 °C. -
Page 26: Gk-405 Readout Box
Align the grooves on the sensor connector (male), with the appropriate connector on the readout (female connector, labeled senor or load cell). Push the connector into place, and then twist the outer ring of the male connector until it locks into place. 16 | TAKING READINGS | GEOKON... -
Page 27: Connecting Sensors With Bare Leads
6.3.2 CONNECTING SENSORS WITH BARE LEADS Attach the GK-403-2 flying leads to the bare leads of a vibrating wire GEOKON sensor by connecting each of the clips on the leads to the matching colors of the sensor conductors, with blue representing the shield (bare). - Page 28 14.7 per 1000 feet (48.5 per km) at 20 °C. Multiply these factors by two to account for both directions. Look up the temperature for the measured resistance in Appendix C. 18 | TAKING READINGS | GEOKON...
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Page 29: Data Reduction
MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | DATA REDUCTION | 19... -
Page 30: Troubleshooting
If the resistance is very high or infinite, the cable is probably broken. If the resistance is very low, the gauge conductors may be shorted. If a break or a short is present, splice according to the instructions in Section 4.4. 20 | TROUBLESHOOTING | GEOKON... -
Page 31: Table 2: Sample Resistance
TABLE 2: Sample Resistance Vibrating Wire Sensor Lead Grid - SENSOR NAME/## Black White Green Shield Black White Green Shield TABLE 3: Resistance Work Sheet MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | TROUBLESHOOTING | 21... - Page 32 22 | TROUBLESHOOTING | GEOKON...
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Page 33: Appendix A. Specifications
A.2 THERMISTOR (see Appendix C also) Range: -80 to +150 °C Accuracy: ±0.5 °C A.3 4000-4 MOUNTING BLOCKS Material: Carbon Steel Plating: Bright Zinc with Clear Chromate MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | SPECIFICATIONS | 23... -
Page 34: Appendix B. Theory Of Operation
Note that the tension (F) can be expressed in terms of strain, e.g., Where: Ɛ is the wire strain (inches/inches). E is the Young’s Modulus of the wire (30 x 10 Psi). Combining the equations from steps four and five gives: 24 | THEORY OF OPERATION | GEOKON... - Page 35 Note: In the previous two steps, T is in seconds x 10 and Ɛ is in microinches per inch. Alternatively: Ɛ = 4.062 x 10 micro strain, where f is the frequency in Hz. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | THEORY OF OPERATION | 25...
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Page 36: Appendix C. Thermistor Temperature Derivation
64.0 21.89K 3000 624.7 176.4 62.5 20.70K 2872 603.3 171.4 61.1 19.58K 2750 582.6 166.7 59.6 18.52K 2633 562.8 162.0 58.3 17.53K 2523 543.7 157.6 56.8 55.6 TABLE 5: Thermistor Resistance versus Temperature 26 | THERMISTOR TEMPERATURE DERIVATION | GEOKON... -
Page 37: Appendix D. Model 4050 Special Instructions
If mounted on concrete, use a K factor of 2 microstrain / C Other gauge lengths are possible with the Model 4050. Consult the factory for additional information. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | MODEL 4050 SPECIAL INSTRUCTIONS | 27... -
Page 38: Appendix E. Temperature Effects
EQUATION 13: Actual Strain is the coefficient of expansion of steel = 12.2 microstrain / C. Where CF 28 | TEMPERATURE EFFECTS | GEOKON... -
Page 39: Appendix F. Temperature Correction When Used On Concrete
= 30 °C Note: Because assumptions have been made regarding the thermal coefficients for the concrete, these equations should only be used as a general guide. MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | TEMPERATURE CORRECTION | 29... -
Page 40: Appendix G. Calculations From Three Strain Gauges, At 60 Degrees, On A Circular Pipe
Y = ±(300 / 3 - 20) = ±80 tan = 80 / 60 = 1.333 and = 53 degrees from the X axis P = ±[60 x 0.6 + 80 x 0.8] + 100 = 200 microstrain, tensile, 0 microstrain minimum 30 | CALCULATIONS | GEOKON... -
Page 41: Appendix H. Two Strain Gauges Mounted One Above The Other
The Axial Strain along the neutral axis = (RE ) / (R–1) The Bending Strain at a distance d – E from the neutral axis = (E ) / (R–1) MODEL 4000 SERIES (4050 INCLUDED) VIBRATING WIRE STRAIN GAUGES | TWO STRAIN GAUGES | 31... - Page 46 GEOKON Phone: +1 (603) 448-1562 GEOKON 48 Spencer Street Email: info@geokon.com is an ISO 9001:2015 Lebanon, New Hampshire Website: www.geokon.com registered company 03766, USA...