Geosense® VWTCM-4600 3D crack meters monitor three-way displacement across cracks and joints in concrete, rock, soil and structures.

The central reference block allows the vibrating wire transducers to show independent movement in all directions, irrespective of each other.

The VWTCM-4600 comprises a 3D mounting frame comprising two arms and two groutable anchors and three vibrating wire displacement transducers complete with built-in thermistors.

Groutable anchors are installed either side of a joint or crack; the installation jig provided ensures that the two anchors are positioned correctly. Once they are set in position the installation jig is removed and the the VWDT-6000 transducers installed. They are positioned against the reference block and typically set to their mid-point.

Any movement in the monitored position will result in relative change between the two anchors which will cause one or more of the VW transducer rods to move independently, thus changing the frequency of the wire. This change in frequency is converted to show the movement in millimetres.

Typically, signal cables run from the sensors to a data logger for remote reading. Alternatively, a terminal/junction box is used and a handheld readout or data logger is used to record the readings manually.

An initial datum reading is taken, which is then compared to all subsequent readings to give the change and magnitude of displacement.