Geokon 4000 Series User manual

©2018, GEOKON. All rights reserved.
Document Revision: DD | Release date: 12/6/18
Model 4000 Series
(4050 included)
Vibrating Wire Strain Gauges
Instruction Manual

WARRANTY STATEMENT
GEOKON warrants its products to be free of defects in materials and workmanship,
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. Upon examination by GEOKON, if the unit is found to be defective, it will be
repaired or replaced at no charge. However, the WARRANTY IS VOID if the unit shows
evidence of having been tampered with or shows evidence of being damaged as a
result of excessive corrosion or current, heat, moisture or vibration, improper specifi-
cation, misapplication, misuse or other operating conditions outside of GEOKON’s
control. Components that wear or are damaged by misuse are not warranted. This
includes fuses and batteries.
GEOKON manufactures scientific instruments whose misuse is potentially dangerous.
The instruments are intended to be installed and used only by qualified personnel.
There are no warranties except as stated herein. There are no other warranties,
expressed or implied, including but not limited to the implied warranties of merchant-
ability and of fitness for a particular purpose. GEOKON is not responsible for any
damages or losses caused to other equipment, whether direct, indirect, incidental,
special or consequential which the purchaser may experience as a result of the instal-
lation or use of the product. The buyer’s sole remedy for any breach of this agreement
by GEOKON or any breach of any warranty by GEOKON shall not exceed the purchase
price paid by the purchaser to GEOKON for the unit or units, or equipment directly
affected by such breach. Under no circumstances will GEOKON reimburse the
claimant for loss incurred in removing and/or reinstalling equipment.
Every precaution for accuracy has been taken in the preparation of manuals and/or
software, however, GEOKON neither assumes responsibility for any omissions or
errors that may appear nor assumes liability for any damages or losses that result
from the use of the products in accordance with the information contained in the
manual or software.
No part of this instruction manual may be reproduced, by any means, without the written consent of GEOKON. The
information contained herein is believed to be accurate and reliable. However, GEOKON assumes no responsibility
for errors, omissions or misinterpretation. The information herein is subject to change without notification.
The GEOKON® wordmark and logo are registered trademarks with the United States Patent and Trademark Office.

I
TABLE OF CONTENTS
1. INTRODUCTION............................................................................................................................................1
2. PRELIMINARY CHECKS......................................................................................................................2
3. GAUGE INSTALLATION.......................................................................................................................3
3.1 CONNECTING THE MOUNTING BLOCKS.......................................................................3
3.2 INSTALLATION ON STEEL SURFACES ............................................................................3
3.2.1 WELDING..............................................................................................................................................3
3.2.2 INSTALLATION ON DRIVEN STEEL PILES ..............................................................................4
3.3 INSTALLATION USING EPOXY CEMENTS....................................................................5
3.3.1 CONCRETE SURFACES ...................................................................................................................5
3.3.2 STEEL SURFACES .............................................................................................................................6
3.4 INSTALLING ON CONCRETE SURFACES USING ANCHOR STUDS.......6
3.5 SETTING THE STRAIN GAUGE ................................................................................................7
4. GAUGE PROTECTION.............................................................................................................................8
4.1 PROTECTION FROM MECHANICAL DAMAGE USING GEOKON
MODEL 4000-6.......................................................................................................................................8
4.2 PROTECTION FROM DIRECT SUNLIGHT AND RAPID CHANGES IN
AMBIENT TEMPERATURE ...........................................................................................................9
4.3 CABLE AND CONNECTOR PROTECTION........................................................................9
4.4 CABLE SPLICING AND TERMINATION............................................................................9
4.5 PROTECTION FROM CORROSION........................................................................................9
4.6 LIGHTNING PROTECTION............................................................................................................9
5. GAUGE LOCATION ................................................................................................................................11
5.1 END EFFECTS...................................................................................................................................... 11
5.2 WELDING EFFECTS........................................................................................................................ 11
5.3 BENDING MOMENTS................................................................................................................... 11
6. TAKING READINGS ............................................................................................................................. 15
6.1 STRAIN GAUGE READOUT POSITIONS ...................................................................... 15
6.2 GK-404 READOUT BOX.............................................................................................................. 15
6.2.1 OPERATING THE GK-404 ........................................................................................................... 15
6.3 GK-405 READOUT BOX.............................................................................................................. 16
6.3.1 CONNECTING SENSORS WITH 10-PIN BULKHEAD CONNECTORS
ATTACHED ....................................................................................................................................... 16
6.3.2 CONNECTING SENSORS WITH BARE LEADS................................................................... 17
6.3.3 OPERATING THE GK-405 ........................................................................................................... 17
6.4 GK-403 READOUT BOX (OBSOLETE MODEL) ........................................................ 17

II
6.4.1 CONNECTING SENSORS WITH 10-PIN BULKHEAD CONNECTORS
ATTACHED........................................................................................................................................ 17
6.4.2 CONNECTING SENSORS WITH BARE LEADS ................................................................... 17
6.4.3 OPERATING THE GK-403............................................................................................................ 17
6.5 MEASURING TEMPERATURES............................................................................................ 17
7. DATA REDUCTION................................................................................................................................. 19
7.1 CONVERSION OF THE READINGS TO STRAIN CHANGES ......................... 19
7.2 CONVERTING STRAINS TO STRESSES....................................................................... 19
8. TROUBLESHOOTING........................................................................................................................... 20
APPENDIX A. SPECIFICATIONS................................................................................................... 23
A.1 VIBRATING WIRE STRAIN GAUGE.................................................................................. 23
A.2 THERMISTOR ...................................................................................................................................... 23
A.3 4000-4 MOUNTING BLOCKS ................................................................................................ 23
APPENDIX B. THEORY OF OPERATION .............................................................................. 24
APPENDIX C. THERMISTOR TEMPERATURE DERIVATION ....................... 26
APPENDIX D. MODEL 4050 SPECIAL INSTRUCTIONS ................................... 27
APPENDIX E. TEMPERATURE EFFECTS ............................................................................. 28
APPENDIX F. TEMPERATURE CORRECTION WHEN USED ON
CONCRETE..................................................................................................................... 29
APPENDIX G. CALCULATIONS FROM THREE STRAIN GAUGES,
AT 60 DEGREES, ON A CIRCULAR PIPE ................................... 30
APPENDIX H. TWO STRAIN GAUGES MOUNTED ONE ABOVE
THE OTHER ................................................................................................................... 31

III
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
FIGURE 10: STRAIN GAUGES MOUNTED ON CENTRAL WEB ....................................11
FIGURE 11: STRAIN GAUGES MOUNTED ON FLANGES .............................................13
FIGURE 12: AXIAL STRAIN MEASUREMENT/BENDING MOMENT ABOUT YY AXIS .13
FIGURE 13: AXIAL STRAIN AND BENDING MOMENTS ABOUT XX AXIS ..................14
FIGURE 14: AXIAL STRAIN AND BENDING MOMENT ABOUT AXIS XX (NOT
RECOMMENDED) .........................................................................................14
FIGURE 15: GK-404 READOUT .......................................................................................15
FIGURE 16: LEMO CONNECTOR TO GK-404 .................................................................15
FIGURE 17: GK-405 READOUT .......................................................................................16
FIGURE 18: MODEL 4050 VIBRATING WIRE STRAIN GAUGE .....................................27
FIGURE 19: THREE STRAIN GAUGES MOUNTED ON A CIRCULAR PIPE DIAGRAM .30
FIGURE 20: TWO STRAIN GAUGES MOUNTED ONE ABOVE THE OTHER .................31

IV
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

V
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............................................................................. 19
EQUATION 7: RESISTANCE TO TEMPERATURE ............................................................ 26
EQUATION 8: READING TO MICROSTRAIN ................................................................... 27
EQUATION 9: GAUGE-ONLY TEMPERATURE EFFECTS ................................................ 27
EQUATION 10: TEMPERATURE-INDUCED STRESS ...................................................... 28
EQUATION 11: APPARENT STRESS ................................................................................ 28
EQUATION 12: LOAD-RELATED STRESS........................................................................ 28
EQUATION 13: ACTUAL STRAIN ..................................................................................... 28
EQUATION 14: THERMAL CONCRETE STRAINS ........................................................... 29
EQUATION 15: ACTUAL STRAIN ..................................................................................... 29
EQUATION 16: STRAIN DUE TO LOAD CHANGES ONLY ............................................. 29
EQUATION 17: AVERAGE AXIAL STRAIN ....................................................................... 30
EQUATION 18: MAXIMUM BENDING STRAIN AROUND THE YY AXIS ...................... 30
EQUATION 19: MAXIMUM BENDING STRAIN AROUND THE XX AXIS ...................... 30
EQUATION 20: MAXIMUM STRAIN ................................................................................ 30

VI