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

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, a 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 Target52632205Three 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 Kit52632210Nine M10x 250mm stainless steel all-thread anchors with washers and nuts. Does not include epoxy grout
Drilling Template52632206Reusable template aids placement of drill holes for anchors
VW DISPLACEMENT TRANSDUCER
60 mm VW Transducer52636388
TypeVibrating wire
Range60 mm
Resolution0.025% FS
Calibration Accuracy±0.1% FS/td>
Repeatability± 0.5% FS
Non-Linearity<.5% FS
Temperature Rating20 to + 80°C
Waterproof Rating17 bar (250 feet)
SIGNAL CABLE
Signal Cable50613824Order signal cable for each transducer. Shielded cable with four 22-gauge, tinned copper conductors and polyvinyl chloride (PVC) jacket.
READOUTS
ReadoutsVW Data Recorder and other pluck-type VW readouts. See separate data sheets for details.
Universal Terminal Box57711600Optional 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 Connector57705001Optional connector. Not required for a terminal box or data logger
DATA LOGGERS
VW MiniLogger for 1 Sensor52613310
4-Channel V-Logger52615140
Campbell Scientific Data LoggersVW 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 Sensor91706150
TypePotentiometer
Range150 mm (6 inches)
Resolution0.03 mm FS (0.001" FS)
Precision±0.15% FS
Waterproof24 bar (348 psi)
Temperature Rating-20 +50 °C
MaterialsStainless Steel (all wetted parts)
Length590 mm closed, 740 mm fully extended, including swivel joint at each end
MountingOne 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