
I
TABLE OF CONTENTS
1. INTRODUCTION............................................................................................................................................1
1.1 THEORY OF OPERATION...............................................................................................................1
1.2 LOAD CELL DESIGN AND CONSTRUCTION ................................................................2
1.2.1 FRICTION BETWEEN THE BEARING PLATE AND LOAD CELL.......................................3
1.2.2 WARPING OF THE BEARING PLATES AND BEARING PLATE DESIGN ......................4
1.2.3 ECCENTRIC LOADING .....................................................................................................................4
1.2.4 ELASTIC BEHAVIOR .........................................................................................................................5
1.2.5 TEMPERATURE EFFECTS...............................................................................................................5
2. INSTALLATION..............................................................................................................................................6
2.1 PRELIMINARY TESTS......................................................................................................................6
2.2 LOAD CELL INSTALLATION .......................................................................................................6
2.2.1 TRANSPORTATION...........................................................................................................................6
2.2.2 INITIAL NO-LOAD READING.........................................................................................................6
2.2.3 INSTALLATION ON TIE-BACKS AND ROCKBOLTS .............................................................6
2.3 CABLE INSTALLATION AND SPLICING ..........................................................................6
2.4 ELECTRICAL NOISE ...........................................................................................................................7
2.5 ENVIRONMENTAL FACTORS ....................................................................................................7
2.6 LIGHTNING PROTECTION............................................................................................................7
3. TAKING READINGS .................................................................................................................................9
3.1 GK-404 VIBRATING WIRE READOUT................................................................................9
3.1.1 OPERATING THE GK-404 ...............................................................................................................9
3.2 GK-405 VIBRATING WIRE READOUT............................................................................ 10
3.2.1 CONNECTING SENSORS WITH 10-PIN BULKHEAD CONNECTORS
ATTACHED ....................................................................................................................................... 10
3.2.2 CONNECTING SENSORS WITH BARE LEADS................................................................... 10
3.2.3 OPERATING THE GK-405 ........................................................................................................... 10
3.2.4 READOUT IN LOAD UNITS........................................................................................................ 11
3.3 MEASURING TEMPERATURES ........................................................................................... 12
4. DATA REDUCTION ................................................................................................................................13
4.1 LOAD CALCULATION ................................................................................................................... 13
4.2 TEMPERATURE CORRECTION FACTOR ...................................................................... 14
5. TROUBLESHOOTING .......................................................................................................................... 16
APPENDIX A. SPECIFICATIONS .................................................................................................. 17
A.1 MODEL 4900 LOAD CELL SPECIFICATIONS.......................................................... 17
A.2 THERMISTOR...................................................................................................................................... 17