CGEO-SG5
Rebar VW Strain Gauge 5
CGEO INTERNATIONAL LIMITED
Installation Manual
2.2.
Rebar Strain Gauge Installation
2.2.1. Model CGEO-SG5
The normal procedure is to weld the Strain Gauge in series with the reinforcing steel that is to
be instrumented on the site. For a typical installation see Figure 3. The Strain Gauge is long
enough so that it may be welded in place without damaging the internal strain gage element
(Figure 1).
However, care should still be taken to ensure that the central portion of the Strain Gauge does
not become too hot as the plucking coil and protective epoxy could melt. In order to prevent
this it may be necessary to place wet rags between the weld area and the coil housing. Also,
take care not to damage or burn the instrument cable when welding. After welding, route the
instrument cable along the rebar system and tie it off every 3-4 feet (1 meter) using nylon cable
ties. Avoid using iron tie wire to secure the cable as the cable could be cut.
Be sure when installing the Strain Gauges to note the location and serial numbers of all
instruments. This is necessary for applying the proper calibration factors and determining strain
characteristics when reducing data.
Guide Wall
Instrument Cables
Diaphragm Wall
Rebar Strain Gauges
(2 places, opposite)
Rebar Reinforcement
Concrete
Tieback
(installed after excavation)
Material to be excavated
Rebar Strain Gauges
(2 places, opposite)
Tieback
(installed after excavation)
Rebar Strain Gauges
(2 places, opposite)
Figure 3 - Model CGEO-SG5 Installation
