
VWCM-4000 crack meters are used to measure movement across surface cracks and joints in concrete, rock, soil and structures.
Overview | GX1 vs GX2 | SUE & Utilities | Structures & Pavements | Software & Outputs | Case Studies | Specifications | Support
Collect high-density, georeferenced GPR data across wide areas and view the subsurface in 3D as you scan. Choose the GX2 array for SUE and utility mapping, or the GX1 array for structural, bridge and pavement investigations.
Best suited to:
Best suited to:
Recommended array: GX2
Recommended array: GX1
Cover more ground
Collect multiple parallel profiles in one pass instead of uilding a grid line by line.
See results during acquisition
View georeferenced radargrams and time-slice information in the field rather than waiting until the data is returned to the office.
Produce repeatable mapped data
Combine wheel-positioned GPR data with GNSS, project coordinates and survey linework.
Use one platform for two very different applications
Exchange GX1 and GX2 arrays without purchasing two complete cart platforms.
The GX2 transforms the GS9000 into a high-density subsurface utility mapping system. Its 11-channel, low-frequency GPR array captures an 83 cm-wide swath in each pass, helping operators detect and map buried pipes, ducts, cables, voids and other subsurface features. Live georeferenced data lets SUE teams review coverage on site and produce accurate CAD, GIS and project-coordinate deliverables.
1. Plan the survey
Load satellite imagery, CAD information, project coordinates or survey control.
2. Collect dense multichannel data
Survey an approximately 0.82 m-wide swath with 11 channels in each pass.
3. Review data live
Examine radargrams, georeferenced time slices and marked features while still on site.
4. Interpret and digitise
Add points, linework, tags, photographs and field observations.
5. Process and deliver
Merge survey areas, apply processing and export mapped information for the customer’s CAD, GIS or reporting workflow.
View the images below to see these in action.
They consist of a sensor outer body tube and an inner free-sliding rod which is connected at the internal end to a vibrating wire sensor by a spring. At the sensor end of the outer body and the external end of the rod anchors are attached which can be fixed either side of a crack to be monitored.
The gauge operates on the principle that a tensioned wire, when plucked, vibrates at its resonant frequency. The square of this frequency is proportional to the strain in the wire. Around the wire is a magnetic coil which when pulsed by a vibrating readout or data logger interface plucks the wire and measures the resultant resonant frequency of vibration.
A change in distance between the anchors caused by the crack opening or closing causes the inner free-sliding rod to move within the outer body which changes the tension on the spring and the vibrating wire thus altering the resonant frequency of the wire.
VWCM-4000 crack meters are installed by grouting, bolting, bonding or fixing expandable anchors to the structure to be monitored. The anchors incorporate ball joints where they are fixed to the gauge to accommodate any differential cross-axis movement and prevent the inner rod from binding within the outer casing.
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The GX1 transforms the GS9000 into a high-resolution structural assessment system for concrete slabs, bridge decks and pavements. Its dense, dual-polarisation array captures detailed 3D data across wide areas, supporting reinforcement and cover mapping, moisture and deterioration assessment, and analysis of asphalt and pavement layers. Live visualisation helps confirm survey coverage on site, while post-processing tools produce clear, report-ready condition maps.
1. Define the inspection area
Import the structure, bridge, pavement or survey background.
2. Collect closely spaced profiles
Capture 35 longitudinal and 15 cross-polarised channels with dense spacing.
3. Review coverage in the field
Use live radargrams and time slices to confirm that the required area has been captured.
4. Process the dataset
Apply velocity, gain, background removal, migration, filtering and topographic correction as appropriate.
5. Generate diagnostic maps
Create depth slices, reinforcement maps, layer information or application-specific condition maps.
6. Integrate with the engineering assessment
Export figures, mapped anomalies and raw data for inclusion in the engineer’s final interpretation and report.
Field information
Processed Diagnostic Information
Engineering deliverables
View some of these features at work below, and our case study if you'd like to see more of what the GS9000 can do.
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GS9000 cart with:

Manual for Geosense's VWCM-4000 range of Vibrating Wire Crack Meters.
Data sheet for Geosense's VWCM-4000 range of Vibrating Wire Crack Meters