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1. Perimetric Joint Meter Assembly User Manual Man115 Manual No User Manual 2 1 1 Revision 04 08 2014 Date Chris Spalton Originator soil INSTRUMENTS Andy Small Chris Rasmussen Checked Authorised for Issue Contents Section i Introduction r 2 3 22 22 Rainer 3 Section 2 General Information 2222422000n0020nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnnn nenne 4 Section 3 Installation Techniques 2s 2222002020nn0nnonnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnunnannnnnnnnnnnnnenn anne 5 3 01 Preliminary RES ne een ae ren asid ane beak Yani engere 5 3 02 Installihg th Gadges sms avin adm enter na din date aude reiner 5 3 03 Initial Setting Base Reading Ni iii 6 3 04 Cabling and Terminal Units 22320 ae ea alu 7 3 05 Cable Jointing with 3M Splice Kit sise 7 3 06 Terminal WES aes cede cote cs los cand Se Ses Re alent rare M M a a on AY Mica oe 7 Section 4 Data Reduction ar ee nennen 9 Section 5 Temperature Correction ua22222uaa200000nn00n0n0nnnannnnnnnannnnnnnannnnnnnannnnnnnannnnnnnannnnnnnnannnnnn 10 Section 6 Environmental Factors 222n0e22nn0nn0nnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnennnnnn ann 11 Section 7 Troubleshooting 4 2 2 eee sb 12 Appendix A Typical Works Calibration Data Sheet 13 User Manual Section 1 Introduction This instruc2. at the transducer gives clear steady signal throughout the range before it is installed Installing the Gauges The relative position of the jointmeter mounting bracket and the reaction target plate mounting bracket will determine the limits of movement of each instrument and its initial setting Once the direction of movement and initial setting has been decided for each installation point fixing of mounting and support brackets for jointmeter and the reaction target plate frames can be proceeded with Accurately mark out on the concrete face at the required construction joint the centres and axes of movement parallel perpendicular normal ensuring that all are precisely parallel etc to the joint making due allowances for the expected range of movement type and dimensions of the gauges joint width reaction target plate dimensions etc Drill suitable holes for the jointmeter mounting and support brackets Bolt these firmly to the concrete face with the expanding masonry bolts supplied bedding into epoxy resin as necessary for intimate contact ensuring perpendicularity of the jointmeter to the reaction plate Follow a similar procedure to mount the respective reaction target plate bracket When no shrink grout or similar epoxy resin used is fully cured the mounting brackets for jointmeter and reaction target plates are rigidly fixed to concrete Smooth polished User Manual stainless steel reaction plate is now assembled to t
3. ble end for approx 150mm Prepare the cable ends as shown Stagger the individual conductor connections Use crimped connectors to join the conductors Ensure Electrical continuity of outer armour screen is re established across joint Use the electrical insulation tape to wrap the connectors Stretch the tape to half its original width and apply one layer half lapped over connector area only Do not wrap the tape beyond the pencilled area Trim the ends of the mould with a sharp knife to suit the diameter of the cable Hold the mould halves in place centred over the splice Snap both halves together and fit the pouring spouts in the holes Ensure that both seams are completely snapped together Tape the ends of the mould body to form a seal Mix the resin thoroughly and maintaining the mould in a level position spouts uppermost pour the resin through one spout until both spouts are completely filled When the resin has solidified and cooled remove the spouts NOTE In cold weather below 15 degrees C the resin becomes very viscous It is therefore advisable to keep the resin in a warm place prior to mixing Mix the compound until its temperature starts to rise this decreases the viscosity Terminal Units The cables are normally terminated in multi channel terminal units The cables enter through waterproof glands The terminal units have a hinged cover secured by two screws Unscrew and open the hinged cover Unscrew the four fixing sc
4. ed Change P K 10 10 P K Ni N1 x 10 from reference setting Ni N1 Gauge Constant K R K R x 10 See Note 1 107 10 No Nr No Nr Where R Calibrated instrument range in millimetres No Nr Initial and full scale calibration readings Ni Reference reading at initial setting P Indicated change in millimetres K Gauge Constant Ni Routine Reading displayed by readout NOTE 1 The works gauge constant may be checked by user after recalibration by using the above formulae NOTE 2 For data on temperature and barometric pressure effects refer to the users manual NOTE 3 Zero reading No must be established by user on site on installation NOTE BAROMETRIC PRESSURE DOES NOT AFFECT VW JOINTMETERS TRIAXIAL User Manual 13 User Manual 14 User Manual 15
5. he bracket with four screws Perimetric jointmeter can now be mounted on the fixed brackets In order to check the initial setting obtains a pre installation base reading No by connecting a readout to the jointmeter with piston rod fully out of the body Pass the jointmeter through the support bracket U bolt and the mounting bracket piston rod facing the reaction target plate Push the piston rod against the reaction target plate and screw the nut on nose mounting thread of the jointmeter Fully tighten the nut The jointmeter piston rod semi spherical head is in firm contact with polished stainless steel reaction target plate 3 03 Initial Setting Base Reading Ni Initial setting of the Triaxial Jointmeter is achieved by assembling it to pre fixed mounting brackets facing the reaction plate When fully assembled the reading will correspond to the position of the piston at a point on its full scale deflection This can be calculated as follows e Obtain the gauge constant of the Jointmeter from its Calibration Certificate e Obtain the pre installation zero reading e Note the current reading with a Vibrating Wire readout in Period x 10 units e Substitute the values in the formula given in the Calibration Certificate Example Gauge Constant K 80 1028 Pre installation Test No 4166 Initial Setting N 5028 Position of piston d at initial setti 80 1028 ga DA rod at initial setting A146 5028 14 91mm The Jo
6. intmeter is set at 14 91mm of its full scale span This method can be used to check the initial setting of each Jointmeter Having finally locked it in position a note of initial zero reference reading Ni must be recorded on the installation sheet of each Jointmeter All subsequent readings from the Jointmeter will represent linear movement of the structure from the time of initial setting Good installation practice requires making a note of date time atmospheric conditions temperature pressure and detail of readout equipment used Having completed the installation and recorded initial reading cables can be routed through the ducts and tubes to a junction box according to procedure described below User Manual 3 04 Cabling and Terminal Units 3 05 3 06 It is possible to use a portable readout or data logger to take readings from Jointmeters individually at the installation point But it is often more convenient to extend the transducer cables to a central location Because vibrating wire transducers have an output signal in frequency rather than current or voltage slight variations in cable resistance have no detrimental effect on gauge readings Consequently splicing has no effect on instrument performance allowing cables to be spliced and routed to junction boxes and then connected to multi conductor cables for transmission to a central location Cable Jointing with 3M Splice Kit Thoroughly scrape all wax and dirt from each ca
7. rews holding the terminal panel and carefully remove it without straining the connecting leads Prepare the cables by stripping and cutting back 20 mm approx of the outer insulation and armour screen Remove the insulation and strip back 5 mm of the conductor insulation Slacken the entry glands and insert the cables Make connections to the contact blocks The earth leads from transducers are not normally connected at the terminal units but leave sufficient lengths available to allow this to be done retrospectively should site User Manual conditions require it Then tighten the glands to grip the cables Replace the terminal panel and secure Connect the readout unit to each instrument in turn to check connections User Manual Section 4 Data Reduction Each Soil Instruments Limited Vibrating Wire Jointmeter is calibrated and comes with a standard Calibration Certificate giving the Gauge constant and temperature at the time of calibration A sample Calibration Certificate is included in this manual as Appendix A Calibration is carried out by pushing in the piston rod to full range while it is coupled to a micrometer Slip gauges can also be used for this purpose by wedging them between the piston rod and the reaction plate Readings are taken at full range displacement a number of intermediate points and at zero extension The gauge factor is then calculated using the expression given in the Calibration Certificate specimen Follo
8. t which can be corrected accordingly Physical dimensional changes due to temperature in the transducer and the structure on which it is mounted are of the order of 10 m m C and can be neglected User Manual Section 6 Environmental Factors Since the purpose of the transducer installation is to monitor site conditions factors which may affect these conditions should always be observed and recorded Seemingly minor effects may have a real influence on the behaviour of the structure being monitored and may give an early indication of potential problems Such factors include but are not limited to blasting rainfall tidal levels excavation and fill levels and sequences site traffic temperature and barometric changes changes in personnel reading the instruments nearby construction activities seasonal changes etc User Manual 11 Section 7 Troubleshooting Maintenance and troubleshooting of vibrating wire Jointmeters is confined to periodic checks of cable connections and maintenance of terminals The transducers themselves are sealed and cannot be opened for inspection If a unit fails to read the following steps should be taken 1 Check the coil resistance Nominal coil resistance is 130 50 plus cable resistance for 22 gauge copper resistance is approximately 10 15m Check resistance across positive negative and earth conductor 2 If resistance is high or infinite a severed cable must be suspected 3 If the resis
9. tance is low or near zero a short must be suspected 4 If the resistance of coil is 130 50 and coil and earth is of a finite value not infinite then a leakage to earth is suspected due to damaged cable 5 If resistances are within the nominal range and no reading is obtained the transducer is suspect and Soil Instruments should be consulted 6 Ifall resistances are within nominal range and readings cannot be obtained on any transducer the readout unit is suspect and Soil Instruments should be consulted 7 If cuts and shorts are located the cable can be spliced in accordance with recommended procedures Soil INSTRUMENTS Bell Lane Uckfield East Sussex t 44 0 1825 765044 e info itmsoil com TN22 1QL United Kingdom f 44 0 1825 744398 w www itmsoil com Soil Instruments Ltd Registered in England Number 07960087 Registered Office 5th Floor 24 Old Bond Street London W1S 4AW User Manual Appendix A Typical Works Calibration Data Sheet Soil Instruments VIBRATING WIRE INSTRUMENT CALIBRATION CERTIFICATE Instrument Type VW JOINTMETER Serial No 50 208 Range 0 to 50 mm Customer Contract Soil Instruments WORKS CALIBRATION DATA Date of Calibration 05 06 89 Gauge Constant mm K 121 1036 Ambient Temperature 21 C Calibrated By Certified By Barometric Pressure 1028 mbars Works File No XXX FIELD READINGS Readout displaying Readout displaying period x 107 frequency x 10 Routine Readings Indicat
10. tion manual describes the techniques required for the installation and reading of the acoustic Vibrating Wire Perimetric Jointmeter It is essential that the equipment covered by this manual should be installed and operated by competent and suitably qualified personnel The techniques described are intended to serve as a general guide and will vary to suit particular site conditions User Manual Section 2 General Information The Soil Instruments acoustic Vibrating Wire Perimetric Joint Meter has been designed specifically for use on concrete faced dams to measure movement across the perimetric joint between the concrete face and plinth either perpendicular or parallel to the perimetric joint in the plane of the concrete face or normal to it However the system is suitable for any application where remote monitoring of the differential movement in three dimensions of adjacent concrete blocks is necessary User Manual Section 3 Installation Techniques 3 01 3 02 Preliminary Tests Upon receipt of the instrument the Jointmeter should be immediately checked for proper operation including the thermistor if included This shall be done after removal of the PVC protective cap To avoid twisting the piston rod pressing in plugger must be used to remove force of the piston from the PVC cap while unscrewing it Due to the strength of the main spring this operation is advised to be carried out by two individuals When the protec
11. tive PVC cap is removed the piston rod will be pushed out by the main spring The jointmeter is ready for preliminary test as follows Connect the gauge leads to the readout unit The reading in Period x 10 units shall be within a band of 3500 to 3800 The reading stability shall be within 1 digit when the Jointmeter is in stationary vibration free environment Pushing in the piston rod by a few millimetres will change the reading which shall return to its original value when the piston rod returns under main spring force A swivel ball joint between piston rod and Transducer spring protects the wire from damage due to rotation of the piston rod As the ball joint is not entirely friction free rotation of the piston rod may cause the wire to twist slightly before the ball rotates in the socket This twist in the wire will result in a change in reading In severe cases the wire which has torsional stresses added to pure tensile stresses will give a distorted signal Check the transducer by pushing the piston rod into the Jointmeter body in small steps At each step a steady reading and clear ring of audio signal indicates a torsion free wire Push the rod in completely i e full range If the audio signal becomes dull with erratic reading during this check the wire is under torsion stress These can be cleared by assisting the ball to rotate in its socket by gently tapping the instrument with a soft object Repeat the check again and ensure th
12. wing the installation instructions the initial reference reading Ni is noted which indicates zero movement Subsequent data obtained from the Jointmeter can be reduced to linear movement in millimetres by using the gauge constant in the equation given in the Calibration Certificate An example of data reduction is as follows Gauge Constant K mm 120 4254 Reference Reading Ni 6320 Zero measurement Example 1 Subsequent Reading N 4820 Equivalent Li M ment P K po 17 ulvaien Inear Movement X s N N Joint opening 21 685mm Example 2 Subsequent Reading N2 6740 10 10 Equivalent Linear Movement 120 4254 er z 16740 Joint opening P 3 6404mm Note A negative sign represents opening up of a joint and vice versa User Manual Section 5 Temperature Correction The transducer working elements are made primarily of steel and stainless steel and are affected by changing temperature to a certain predictable degree In case of large temperature changes application of temperature correction will improve the accuracy of the measurements The approximate temperature effect on the gauge is 0 0125mm per degree Celsius Hence for a temperature increase of 10 C a transducer will indicate 0 0125 x 10 0 125mm reduction in linear measurement Correction is applied by adding 0 125mm to the result indicated by the transducer reading A fall in temperature will result in a positive change in linear measuremen
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