Soil Instruments 1030, User Manual

Page 1: ...User Manual 1 Vibrating Wire Embedment Strain Gauge User Manual Man142 6 1 0 06 08 14 P Day Andy Small Chris Rasmussen Manual No Revision Date Originator Checked Authorised for Issue ...

Page 2: ...nstallation in Pre cast blocks 7 Section 4 Protection of the Installation 8 Section 5 Cable Routing and Protection 9 Section 6 Monitoring 10 Section 7 Data Interpretation 11 Section 8 Temperature Effects 13 Section 9 Troubleshooting Guide 14 Appendix A Vibrating Wire Data 15 Appendix B Troubleshooting Flowchart 16 Appendix C CE Declaration 17 ...

Page 3: ...lege London and incorporate the latest materials and techniques to make these gauges suitable for use in hostile conditions The nature of the instrument dictates that it is used to measure changes in strain i e change in length per unit length The gauges are designed for use in installations where they are cast directly into the mass of the concrete structure The pre casting of the gauges into bri...

Page 4: ...er each barrel see Figure1 to protect the gauge barrel when it is tied to support bars during mounting Although gauges are checked prior to leaving Soil Instruments damage can occur during transit It is suggested that the gauges are visually checked immediately upon receipt Additionally it is prudent to check the operation using a vibrating wire readout device to ensure steady readings if an audio...

Page 5: ... pre casing into a concrete block which is then cast into the main concrete pour When affixing gauges to rebar for direct encasing into concrete care must be taken to avoid over range forces being applied to the gauge end blocks by the speed and or weight of concrete being poured Do not tie the gauge too tightly to the rebar as this can move during pour and or curing and thus damage the gauge If p...

Page 6: ...ve to the above small rebar sections cut to length can be used to replace the soft steel wire with cable ties attaching these short lengths to the gauge and the main rebar If this method is selected under no circumstances over tighten the cable ties so that no movement is allowed An indicative picture is below ...

Page 7: ...Fill the mound and position the gauge in the middle of the fill Do not cure for more than 3 days or less than one day Place blocks in position in main pour note comments on cable protection to follow in section 4 TABLE INDICATING SUGGESTED DIMENSIONS FOR SUPPORT BARS Refer to Figure 1 Gauge Length A B 150 mm 90 mm 8 mm INFORMATION If the reinforcement spacing exceeds 3 x A then bar size B should b...

Page 8: ...inforcement performance Where the gauge is installed in a vulnerable position good practice is to spray the area with marker paint as a warning and or cover the area with fine wire mesh It may be necessary to fix additional reinforcement steel around the gauge position to offer protection during concreting though this could affect subsequent gauge readings ...

Page 9: ...e cables especially where movement loading could take place when placing the cage The reinforcement bars can be used to protect the cables for example by running the cables under the bars to reduce the risk of damage where vibrating pokers are to be used Where significant movement could take place the cable ties should be left a little slack and sufficient cable left free and positioned so that it...

Page 10: ... Where loading tests are to be performed the Base reading for the test data should be recorded just prior to the beginning of the test Data from Vibrating Wire instruments can be recorded in 3 formats Period Linear or Engineering Units The required format should be established prior to any test beginning and remain consistent for the duration of the monitoring program The Soil Instruments Model 10...

Page 11: ...ied with each gauge Please note when is positive the resultant strain is tensile Linear Units Where Change in micro strain Gauge Calibration Constant Base reading in units Current reading in units Batch Factor supplied with each gauge Please note when is positive the resultant strain is tensile The calculation of Load in a member using data from strain gauges is often complex The fundamental probl...

Page 12: ...ipe outside diameter 1 016m Steel pipe inside diameter 0 984m Calculated change from the strain gauges 54 688 Young Modulus of Elasticity of the steel pipe 200 000 000 000 N m Stress E x 200 000 000 000 x 0 000054688 10937600 N m Area r x outside diameter 2 x inside diameter 2 x 1 016 2 x 0 984 2 x 0 508 x 0 492 x 0 258064 x 0 242064 0 810732 m 0 760466 m 0 050266 m Force S x A 10937600 x 0 050266...

Page 13: ... in the concrete if the concrete is restrained these are superimposed on other load related stresses Differences between the coefficient of expansions of the concrete and that of the steel in the strain gauge itself give rise to an apparent change in strain in the concrete This apparent change can be corrected for using the equation below corrected 0 1 Temp Temp x TC TC c g Where is the change in ...

Page 14: ...uctors and earthing screen of the electrical cable If continuity exists a damaged cable is confirmed Step 2 The resistance across the two conductors of the electrical cable should be checked This can be done using a multimeter device across the two exposed conductors if the cable has not been connected to a terminal cabinet or can be done just as easily across the two conductors if the instrument ...

Page 15: ...its Period Units represent the time taken for the wire to vibrate over one full oscillation expressed in seconds Due to the very small size of the number generated most equipment manufacturers display the unit multiplied by 10000000 or 10 7 The relationship between Period Units and frequency units is expressed as P µ 1 Frequency Period units are therefore convenient to measure but do not have a li...

Page 16: ...ected Check reading of instrument with another unit A damaged cable is suspected causing a short See step 4 A severed cable is suspected causing very high or infinite resistance It must be suspected that the portable logger used first is faulty Contact Soil Instruments Ltd A faulty instrument is possible Contact Soil Instruments Ltd Is reading OK with alternative logger Does a continuity exist bet...

Page 17: ...User Manual 17 Appendix C CE Declaration ...

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Page 20: ...East Sussex TN22 1QL United Kingdom t 44 0 1825 765044 e info soilinstruments com w www soilinstruments com Soil Instruments Ltd Registered in England Number 07960087 Registered Office 3rd Floor Ashley Road Altrincham Cheshire WA14 2DT ...