JOINT METERS (VW)
Vibrating wire (VW) joint meters are used to monitor joints of mass concrete structures. The instrument consists of two parts, a socket and the main body with a waterproof vibrating wire sensing gauge. During construction of the structure, the socket is secured to the form and embedded into a lift of the block to be constructed. After removal of the form and prior to concreting of adjacent block, the gauge is screwed into the socket, set to the desired range, and then embedded into the concrete. Opening and closing of the joint is measured by the gauge, which is anchored in both blocks. All measurements are compared to an initial datum reading, providing a history of magnitude and rate of movement at the joint.
Four different ranges: 12.5, 25, 50 and 150 mm
Accuracy of 0.1% to 0.2% F.S.
Resolution of 0.02% to 0.025% F.S.
Long-term stability in difficult environments
Accommodates shear movement
Can monitor both new and existing cracks
Temperature ranges from -20C to +80C