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Strain Gauges

Rebar Strainmeters (Electrical Resistance) | Model 3911 · 3911A

  • Model 3911A (front) and 3911 (#4 rebar) “Sister Bar” (rear) Rebar Strainmeters.
  • Model 3911 and 3911A Rebar Strainmeter components and overall dimensions.
Model 3911 · 3911A

Model 3911 Electrical Resistance Type Rebar Strainmeters are designed primarily for monitoring the stresses in reinforcing steel in concrete structures, such as bridges, concrete piles and diaphragm walls. They are particularly suitable where dynamic strain measurements are required in addition to static strains, or where existing readout systems or dataloggers are not capable of reading vibrating wire sen­sors. The Model 3911, or "Sister Bar," is designed to be wire tied in parallel with the structural rebar. The small diameter of the bar minimizes its effect on the sectional modulus of the concrete. Larger models (3911A) are available for welding directly into structural rebar.


Standard Range
3000 µε
0.4 µε
±0.25% F.S.
0.25% F.S.
Bridge Resistance
350 Ω
Temperature Range²
−20 °C to +80 °C
Rebar Sizes
3911 | #4 (Sister Bar)
3911A | #5, 6, 7, 8, 9, 10, 11, 12, 14
3911 | 914 mm
3911A | 1105 mm

¹Accuracy established under laboratory conditions.

²Other ranges available on request.

Compatible Readouts and Dataloggers

Please Note: GEOKON maintains an ongoing policy of design review and reserves the right to amend products and specifications without notice. Various instruments are discontinued over time and replaced with new, updated models.