Geokon 4911, Руководство по установке, Страница: 7 / 27

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1. INTRODUCTION
Geokon Vibrating Wire Rebar Strain Meters are designed primarily for monitoring the stress
exerted upon reinforcing steel inside concrete structures, such as bridges, concrete piles, and
diaphragm walls. The strain meter comprises a length of high strength steel, bored along its
central axis to accommodate a miniature vibrating wire strain gauge. Both models of strain
meters are robust, reliable, and easy to install and read. They are unaffected by moisture, cable
length, or contact resistance. The long-term stability of these instruments has proven to be
excellent.
Readout of the load or stress is achieved remotely using a portable readout or datalogging system
available from Geokon. Each strain meter is supplied with a calibration report, which shows the
relationship between readout digits and microstrain. The calibration report also shows the initial
no load zero reading.
Model 4911 Vibrating Wire Rebar Strain Meter or “Sister Bar” (Figure 1) comprises a short
length of high strength steel welded between two sections of reinforcing bar. It is designed to be
wire tied in parallel with structural rebar. The small diameter of the 4911 minimizes its affect on
the sectional modulus of the concrete. The cable exits the strain meter through a small block of
protective epoxy.
Figure 1 - Model 4911 Rebar Strain Meter
Model 4911A Vibrating Wire Rebar Strain Meter (Figure 2) comprises a short length of high
strength steel welded between two sections of reinforcing bar. It is designed to be welded
between sections of structural concrete reinforcing bar. The cable exits the strain meter via a
compression fitting.
Figure 2 - Model 4911A Rebar Strain Meter