3D Jointmeters

VW 3D Jointmeters

Applications

3D Jointmeters are used to monitor movement at joints and cracks. Submersible sensors for 3D jointmeters are designed to withstand extended underwater operation. Typical applications include:

  • Monitoring movement at submerged construction joints in concrete dams.
  • Monitoring joints or cracks in tunnels and tanks.
schematic diagram of 3d jointmeters in use

Operation

3D jointmeters consists of three submersible displacement sensors and a mounting system. The exact design of the mounting system, which consists of a reference bracket and and three end brackets, depends on site specific details, such as the height of the joint covers and the degree of protection required. The drawing above illustrates the concept. In practice, the brackets are often designed by engineers at the site.

Two types of sensors are available: VW sensors, which are suitable for pressures up to 17 bar and and potentiometers, which are suitable for pressures up to 24 bar. The sensors are mounted parallel to the axis of expected movement. A change in the distance across the joint causes a change in the signal output by the sensor.

The initial reading is used as a datum. Subsequent readings are compared to the datum to calculate the magnitude, rate, and acceleration of movement at the joint.
 

Advantages

Submersible

Two types of sensors are available.

  • The vibrating wire sensor is rated for 17 bar (250 psi) of water pressure.
  • The potentiometer-based sensor is rated for 24 bar
    (348 psi) of water.
Easy Installation

Installation requires only small diameter, shallow drill holes in the concrete slab.

Manual or Automatic Readings

The jointmeter is easily connected to a data logger for unattended monitoring.

For more information

Please download the VW 3D Jointmeter datasheet and manual or the Potentiometer-based submersible sensor datasheet and manual
These documents can be viewed and printed with Adobe Reader.

VW 3D Jointmeters Specifications

3D JOINTMETER COMPONENTS
The VW 3-D Jointmeter consists of several components that are ordered separately. Required components include three VW displacement sensors, signal cable for the sensors, and one 3-D mounting system. Accessories include anchors and a reusable mounting template.
3-D MOUNTING SYSTEM
Sensor Mount and Target 52632205 Three aluminum brackets, six universal joints, and necessary hardware. Does not include anchors. Overall dimensions of the 3-D jointmeter, with transducers,are: 965mm deep, 790 mm wide, and 520 mm high (38" x 31" x 20.5")
Anchor Kit 52632210 Nine M10x 250mm stainless steel all-thread anchors with washers and nuts. Does not include epoxy grout
Drilling Template 52632206 Reusable template aids placement of drill holes for anchors
VW DISPLACEMENT TRANSDUCER
60 mm VW Transducer 52636388
Type Vibrating wire
Range 60 mm
Resolution 0.025% FS
Calibration Accuracy ±0.1% FS/td>
Repeatability ± 0.5% FS
Non-Linearity <.5% FS
Temperature Rating 20 to + 80°C
Waterproof Rating 17 bar (250 feet)
SIGNAL CABLE
Signal Cable 50613824 Order signal cable for each transducer. Shielded cable with four 22-gauge, tinned copper conductors and polyvinyl chloride (PVC) jacket.
READOUTS
Readouts VW Data Recorder and other pluck-type VW readouts. See separate data sheets for details.
Universal Terminal Box 57711600 Optional terminal box provides connections for 12 sensors and an indicator. Sensors selected by rotary switch. Weatherproof fiberglass box measures 290 mm wide x 345 mm high x 135 mm deep (11.5 x 13.5 x 5.25")
Universal Connector 57705001 Optional connector. Not required for terminal box or data logger
DATA LOGGERS
VW MiniLogger for 1 Sensor 52613310
4-Channel V-Logger 52615140
Campbell Scientific Data Loggers VW displacement transducers connect directly to the VW MiniLogger, V-Logger and Campbell Scientific CR6. Campbell Scientific CR800 or CR1000 require an AVW200 vibrating wire adapter. See separate data sheets.

Submersible Jointmeter Sensor Specifications

SUBMERSIBLE SENSOR
Submersible Sensor 91706150
Type Potentiometer
Range 150 mm (6 inches)
Resolution 0.03 mm FS (0.001" FS)
Precision ±0.15% FS
Waterproof 24 bar (348 psi)
Temperature Rating -20 +50 °C
Materials Stainless Steel (all wetted parts)
Length 590 mm closed, 740 mm fully extended, including swivel joint at each end
Mounting One end of the sensor is fixed to the reference bracket by an M10 bolt (supplied). The other end of the sensor is fixed to the end bracket by an M10 all thread rod (supplied), which can be cut to the required length