Extensometers & Jointmeters

DIGITAL TAPE EXTENSOMETER

Geotechnical instrumentation_Geozone Geoservices_Digital tape extensometerTape extensometer is used to take accurate distance measurements between pairs of target points that have been permanently installed. The instrument is a removable stainless steel measuring tape with equally-spaced punched holes incorporated in an aluminium and stainless steel body with external pneumatic tensioning device and incorporated dial gauge. At the same time, the tape extensometer provides constant tension on the tape and accurate readings on the dial gauge. A portable compressor provides compression air to adjust the tape tension during measurements. Typical applications include convergence monitoring of tunnel linings, according to NATM practice, and of shafts, underground openings and caverns.

Technical Specifications

0DNP0150000 15 M TAPE
0DNP0300000 30 M TAPE
0DNP0CF1100 CALIBRATION FRAME
Digital gauge 5 digits LCD, 6mm height
Gauge range 100 mm
Gauge resolution 0.01 mm
Repeatabilty ± 0.1 mm
Tape width 13 mm
Tape scale division centimetre punched every 25mm
Body diameter 60 mm
Overall length 870 mm

REFERENCE BOLTS
A wide range of measuring bolts are available that can be grouted, welded or anchored to the structure.

0DN0CH20000 200mm groutable 3/8” stud bolt
0DN0CH50000 500mm groutable 3/8” stud bolt
0DN0CHE1000 1000mm groutable 3/8” stud bolt
0DN0CH05000 weldable 3/8” stud bolt
0DN0CH20E00 200mm groutable eyebolt
0DN0CH05E00 weldable eyebolt
0DN0TS10E00 wall eyebolt

REMOVABLE TARGETS
(Product code 0GCTR005000)
Reflective targets allow automatic convergence monitoring by topographic total station. Designed to fit the 3/8” stud convergence bolts by its own adaptor.

0GCTR38ADS0 3/8”G stainless steel stud adaptor
0GCTR38ADP0 3/8”G plastic stud adaptor

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MECHANICAL JOINTMETERS

Geotechnical instrumentation_Geozone Geoservices_Mechanical jointmetersA wide range of mechanical crackmeters (jointmeters) are produced in order to provide for all client requirements. The removable extensometer allows the measurement of relative movements between two reference pins positioned across the joint (fissure). The extensometer, which comes with its own portable, storage case, has a precise sliding rail with adjustable base length. Uniaxial and 3-D (triaxial) mechanical jointmeters are also available to monitor joints and cracks. The movements between the two anchors are obtained with mechanical dial gauges. Simple and inexpensive, the TT-1 tell-tale crack monitor installed across a fissure allows the crack survey to be conducted in two directions.

REMOVABLE EXTENSOMETER
(Product code 0DF250C5000)

Measuring range 50mm
Base length adjustable at 200, 300 or 500mm
Resolution 0.01 mm
Repeatability better than ±0.02mm
Accessories
0DF25PIN200 UNIAXIAL CRACKMETER
0DF20TKIT00 3-D CRACKMETER ASSEMBLY
MECHANICAL JOINTMETERS
0D3101D3000 UNIAXIAL CRACKMETER
0D3103D3000 3-D CRACKMETER ASSEMBLY
Mechanical range 0-30mm (±15) in all directions
Base lengths 500 mm (uniaxial) or 200 mm (3-D triaxial)
DIAL GAUGE KIT
(Product code 0DIG30KIT00)
Measuring range 0-30mm (±15) in all directions
Resolution 0.01 mm
Accuracy 0.05 mm
TELL-TALE CRACK MONITOR
(Product code 0D300LINE00)
TT-1 type 2-D biaxial
Mechanical range ±25 mm in both directions
Resolution 0.01 mm
Accuracy 0.05 mm

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DBS MEASURING ANCHORS

Geotechnical instrumentation_Geozone Geoservices_DBS Measuring anchorsMeasuring anchors are a combination of rock bolt and extensometer. They are used to evaluate the performance of rock anchors in all types of applications. Measuring anchor consists of a hollow anchor body with inside installed a 4-point mini extensometer with anchor points at 4 different levels. Sisgeo measuring anchor is available for nominal load of 250KN with lengths of 4,6 or 9 meters. Readings are taken manually by a dial gauge or could be also automated by using vibrating wire displacement transducers.

Technical Specifications

0DBS2503244 DBS 4M LONG
0DBS2503264 DBS 6M LONG
0DBS2503294 DBS 9M LONG
Loading capacity 250 KN
Anchoring points 4
Overall outer diameter 38 mm
Drilling diameter 50 mm
Materials:
– Rods iron
– Central anulus brass
– Head Stainless steel
MANUAL MEASURING EQUIPMENT
(Product code 0DIG10KDBS0)
Range 0 – 10 mm
Resolution 0.01 mm
4-FOLD VIBRATING WIRE MEASURING HEAD
(Product code 0DBS04DTE00)
Displacement transducer 4 nos. vibrating wire
Range +/- 5mm
Resolution 0.01 mm
Accuracy < 0.5% FS
Operating temperature -20°C +80°C
Signal output frequency
Dimension Length 270mm, OD 54mm

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BOREHOLE ROD EXTENSOMETERS

Geotechnical instrumentation_Geozone Geoservices_Borehole rod extensometersRod extensometers are installed in boreholes in order to monitor displacements at various depths using rods of different materials and lengths. A pre-set length of measuring rod is inserted into a nylon tube to avoid soil friction and its tip is fixed to a steel groutable anchor. Preassembled fibre glass rods are coiled when manufactured and shipped ready for installation. Stainless steel and invar rods are supplied in bars of 2 metre lengths and need to be mounted on-site. The complete rod extensometer assembly is grouted through a dedicated tube, but at the same time, allowing free movement of each rod within its sleeve.

Technical Specifications

0D222AC00A0 s/steel or invar rods, DTE < 100 mm
0D222AC00B0 s/steel or invar rods, DTE > 100 mm
0D222FG00A0 fibre glass rods, DTE < 100 mm
0D222FG00B0 fibre glass rods, DTE > 100 mm
Number of bases 1 (single), from 2 to 7 (multiple)
Multiple head top tube OD 120 mm
Extensometer rods FG fibre glass continuous
AC stainless steel, 2 m sections
IN invar, 2 m sections
Protective sleeve nylon 11 (rilsan), OD 12 mm
Groutable anchor FG: rebar 16mm OD, 400 mm long
AC/IN: rebar 22m OD, 400 mm long
System Components
0D221BMFG00 FIBRE GLASS ROD, 0D 7mm
0D221BMAC00 STAINLESS STEEL ROD, OD 8mm
0D221BMIN00 INVAR ROD, OD 8 mm
0D222TOP200 PROTECTIVE CAP, DTE: 10, 25, 50mm
0D222TOP320 PROTECTIVE CAP, DTE: 100,150,200mm
0D222KTOP01 SINGLE BASE CAP KIT
0D222K7AC00 INSTALLATION KIT FOR AC/IN RODS
0D222K6FG00 INSTALLATION KIT FOR FG RODS
DIGITAL GAUGE
(Product code  0DIGD020000)
Measuring range from 0 to 200mm
Resolution 0.01 mm

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DISPLACEMENT TRANSDUCERS

Geotechnical instrumentation_Geozone Geoservices_Displacement transducersBorehole rod extensometers could be simply read with mechanical depth gauge. The mechanical system is easily converted to provide an electrical output for remote monitoring and data acquisition. An electrical or vibrating wire linear displacement transducer is fitted to each extensometer rod on the instrument head. The range of the displacement transducer is selected to match the rod displacement. The transducer can be adjusted on the extensometer head to trim the zero position. An electric cable connects the displacement transducers to the measuring box for manual readings with portable readout, or to the ADK-100 automatic data acquisition system.

Technical Specifications
DTE DISPLACEMENT TRANSDUCERS
DTE transducers are available either with linear potentiometer or vibrating wire transducer.

Linear Potentiometers
Measuring range 25, 50, 100, 150, 200mm
Resolution 0.01 mm (depending of readout)
Accuracy <0.3% FS
Signal output 4-20 mA (current loop)
Power supply 12-24V DC
Operating temperature -20°C +60°C
Overall diameter 16 mm
Environmental IP68 (watertight up to 200 kPa)
Vibrating Wire Transducers
Measuring range 25, 50, 100, 150 mm
Resolution 0.01 mm (depending of readout)
Accuracy < 0.5% FS
Signal output frequency
Operating temperature -20°C +80°C
Overall diameter 16 mm
Environmental IP68 (watertight up to 200 kPa)

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EMBANKMENT EXTENSOMETERS

Geozone Geoservices_Geotechnical instrumentation_Embankment extensometersEmbankment (soil) extensometers are used to measure soil strains in large earth structures. During the construction stage, the embankment extensometers are usually incorporated in the filling material. The system consists of a number of anchor plates connected by extension rods to the measuring elements. The measuring element is a telescopic tube equipped with a vibrating wire displacement transducer to monitor the change in distance between two anchor plates. A number of elements may be chained together by means of 1, 2 or 3 m extension rods. Vibrating wire displacement transducers are available in different ranges for measuring up to 150 mm of displacement.

Technical Specifications

System Components
0D2320BM100 EXTENSION ROD, 1 M
0D2320BM200 EXTENSION ROD, 2 M
0D2320BM300 EXTENSION ROD, 3 M
0D111PV5500 PVC CORRUGATE ANTIFRICTION SLEEVE
0D232AN5000 ANCHOR PLATE, DIAM 500 MM
0D232AN5500 ANCHOR PLATE, 500×500 MM
MEASURING ELEMENTS
0D232T050VW 50 mm (±25) range
0D232T100VW 100 mm (±50) range
0D232T150VW 150 mm (±75) range
Type of sensor vibrating wire with built-in thermistor
Measuring range 50, 100, 150mm
Resolution 0.01 mm (depending of readout)
Accuracy <0.5% FS
Signal output frequency
Operating temperature -20°C +80°C
Material stainless steel

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CRACKMETERS AND JOINTMETERS

Geozone Geoservives_Geotechnical Instrumentation_Crackmeters & jointmetersCrackmeters and jointmeters are used to monitor movements across surface cracks and joints in concrete structures or rock. The instrument assembly includes a sensor housing and a target. Both parts are equipped with screw anchors. Typically, the anchors are bolted on the opposite sides of the joint (crack). The displacement transducer housed in the sensor body is positioned across the joint/crack which enables measurement of the changes in the distance between the anchors. CRID is an integrated system for fissure monitoring of building and monuments, which reduces the visual impact. CRID includes four miniature fissure meters (sensors) connected by signal cable to a compact, battery-powered datalogger for automatic data acquisition.

Technical Specifications

Linear potentiometer transducers
Full scales 10, 25, 50, 100, 150mm
Resolution 0.01 mm (dependent of readout)
Total accuracy ± 0.3% FS including linearity and hysteresis
Signal output 4-20 mA (current loop)
Power supply 12-24V DC
Operating temperature -20°C +60°C
Sensor diameter 16 mm
Anchor distance 500 mm
Environmental IP68 (watertight up to 200 kPa)
Material stainless steel
Vibrating wire transducers
Full scales 10, 25, 50, 100, 150mm
Resolution 0.01 mm (dependent of readout)
Total accuracy <0.5% FS including linearity and hysteresis
Signal output frequency
Operating temperature -20°C +80°C
Sensor diameter 16 mm
Anchor distance max 500 mm
Environmental IP68 (watertight up to 200 kPa)
Material stainless steel
Accessories for 2-D and 3-D monitoring
0D31Y1DTE00 Y-AXIS FIXING PLATE
0D31Z1DTE00 Z-AXIS PAIR OF FIXING PLATE

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WIRE CRACKMETER AND DEFORMETER

Geozone Geoservices_Geotechnical Instrumentation_Wire crackmeter & deformeterWire crackmeter is used to monitor the changes in the distance between two anchor points located up to 30 m apart. Typical applications include measurements of large displacements associated with landslides, monitoring of rock-masses, masonry cracks and surveying of earth faults. The wire crackmeter consists of a stainless steel transducer box and target assembly made by an eyebolt expansion anchor. The electrical deformeter is used to monitor the displacement between two opposite surfaces and convergence in underground openings and tunnels. The displacement transducer is housed in a stainless steel body mounted on a fixing plate for wall/floor installation. A Kevlar rope forms the connection between the transducer and the target.

Technical Specifications

WIRE CRACKMETER
(Product code 0D241A20000)
Mechanical range 2000 mm
Sensitivity 0.03 mm
Accuracy ±1 mm (depends mainly from the thermal effects on the wire)
Repeatability ±0.03 mm
Signal output 4-20 mA (current loop)
Operating temperature -20°C +60°C
Wire diameter 2 mm, stainless steel
Max. wire tension 8 Kg
Base (wire) length up to 30 meter distance between transducer and target
Transducer housing 300x200x185 mm
Target assembly eyebolt expansion anchor
WIRE DEFORMETER
(Product code 0D313F00000)
Type of sensor linear potentiometer or vibrating wire
Signal output 4-20 mA, frequency
Measuring range 25 mm (±12.5), 50 mm (±25)
Resolution 0.01 mm (depending on readout)
Total accuracy <0.3%FS (4-20mA)
<0.5%FS (vibrating wire)
Operating temperature -20°C +60°C
Wire Kevlar rope
Base (wire) length up to 10 meter
Sensor housing 16mm diam.

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FIXED EXTENSOMETERS

Geozone Geoservices_Geotechnical instrumentation_Fixed extensometersFixed extensometer is a device placed in embankment fill or inside a borehole for monitoring settlement or heave between two points, without using a removable probe. The settlement platform or the tell- tale extensometer can be used, based on a string of settlement rods. These are, respectively, connected to a plate buried at the embankment foundation level or to a datum point grouted inside the borehole in firm soil. Optical levelling at the top of the riser rod provides precise monitoring. Electrical transducers can be used for automatic remote readings even in inaccessible locations.

Technical Specifications
SETTLEMENT PLATFORM
The primary advantage of the settlement platform is its simplicity. The settlement platform consists of a galvanized square plate to which a riser settlement rod is attached. Anti-friction corrugate pipe is placed around the riser rod. Optical levelling measurements to the survey point mounted on the top cap provides a record of plate elevation.

0D100A20000 2M SECTION RISER ROD
0D111PV5500 CORRUGATE PIPE, OD 55mm
0D100B05000 SQUARE PLATE 500x500mm
0D100T15000 TOP CAP AND SURVEY POINT

TELL-TALE EXTENSOMETER
The tell-tale extensometer is a single-point extensometer which is, typically, used for precise monitoring of ground surface settlement or heave. It consists of a stainless steel bottom anchor to which a string of riser measuring rods is attached. Anti-friction corrugate pipe is placed around the riser rods. Optical levelling measurements of the top head of the riser rod provides a record of ground settlement. Sliding rings are located at both ends in order to prevent down drag forces on the rod.

0D100A20000 2M SECTION RISER ROD
0D111PV5500 CORRUGATE PIPE, OD 55mm
0D100TT6000 BOTTOM ANCHOR
0D100TT0100 TOP CAP AND SURVEY POINT
0D100TTEL10 DTM MEASURING HEAD

DTM ELECTRICAL TRANSDUCERS
(Product code 0DTM0000000)
DTM electrical transducers can be mounted on either settlement platforms or the tell-tale extensometers.

Range 250mm, 500mm, 1000mm
Total accuracy 0.25% F.S.
Output signal 4-20 mA

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s/steel or invar rods, DTE > 100 mm