> Detailed description of G6 gauge
The purpose of the G6 gauge is to measure variations in the opening and rotation of the edges of a crack, or of any sort of joint, in a single plane.
The combined use of 2 verniers, for translational movement and rotation, allows the device to indicate the variations in distortion subject to different types of stress.
This device is recommended for studying a phenomenon seen as distortion or a crack with billiard cue edges.
This G6 Saugnac Gauge is based on the same two concepts:
- Measurements are made using a vernier measuring to 1/10th of a mm.
- It is fixed in place using double-sided self-adhesive tabs or mechanical means (plugs and screws)
The plate of the G6 gauge is 1 mm thick PVC. It is 120 X 95 mm.
The sliding tongue is in 0.5 mm thick PVC. The total thickness is 3 mm and the length of the gauge with the tongue in position is 20 cm.
The force necessary to move the device is 20 g for traction and 35 g for rotation.
A : Axis of rotation , B : Crack
A 1 division variation on the circular scale corresponds perceptibly to 3.3 mm
of vertical differential movement when the
pointer T of the vernier indicates a value near 10.
The G6 gauge can be protected by a sheet of transparent PVC 150 X 300 X 1.1 mm.
This protection is recommended e.g. when the gauge is being used in busy areas, schools or public places.
Fixing the G6 gauge and its protective cover with plugs and screws
On smooth surfaces, partitions, interior walls with paint, wallpaper or thin plaster coating, use of the self-adhesive tabs will be sufficient.
For damp surfaces lacking adhesion properties or on surfaces not capable to receive adhesive tabs, use mechanical fixings such as impact anchors.
Two G6 gauges positioned at right angles to each other make it possible to define more precisely the complex movements analysed by 4 verniers.
The G6 gauge is pre-drilled with 3 ° 4 mm holes.
> Using a G6 gauge with an angle bar
To measure and record complex changes in a joint or crack in several perpendicular planes we recommend using G6 gauges placed at right angles to each other, attached if necessary, to angle bars (plate and sliding tongue). Movements are thus analysed by several verniers.
> Example of installation
Example of installation in a special case necessitating using a form of extension and a widened surface to which to affix the plate. Ingenious installation strategems, usually simple, are required in certain cases. Examples of installation Complex cracks
Example of installation with extension
Complex cracks require using several G6 gauges to analyse the phenomenon that caused the damage.