A strain gauge is constructed by bonding a fine electric resistance wire or photographically etched metallic
resistance foil to an electrical insulation base using an appropriate bonding materials , and attaching gauge
leads.
-1 STRAIN GAUGE
Other types :
2- Ultrasonic Concrete tester
3- Waterproof strain gauge
4- Bolt strain gauge
5- Joint-Meter
These models are used to measure joint opening displacement of mass concrete
6- Shear Displacement Transducer
The KU-A shear displacement transducer is used to measure the shear displacement of a joint between
tunnel bedrock and concrete lining or the shear displacement between two concrete layers of a concrete
structure (concrete placed first and that placed next). This transducer is installed on the anchor bolt driven
into tunnel bedrock or first-placed concrete, then concrete lining or another layer of concrete is laid to
sandwich the transducer for shear displacement measurement.
The micro-creep meter is used to measure the displacement in underground concrete tanks
or tunnels. Specifically, it measures microscopic displacements by measuring the distance
between two points set at an interval of 1 m to 10 m. The micro-creep meter is set at one
point and a super-invar wire fixing bracket is set at the other point, each secured using anchor
bolts. A super-Invar wire is then set up between these two points to measure the distance.
This meter is mainly used to control the conditions of work execution.
7- micro-creep meter
8- Center-hole type Load Cell
The KCE-NA load cell is a center-hole type load cell designed to use in tension
measurement of anchoring strand. It can deliver stable measurement performance under somewhat eccentric load.
9- Soil Pressure Gauge
The soil pressure gauges each 200 mm in outside diameter. They are widely used at construction sites.
They are designed with a dual-diaphragm structure that can minimize the displacement of a sensing area
and thereby can keep the stress distribution in soil undisturbed under pressure. With the KDA-PA, the
Input / Output cable comes from the side of body. With the KDB-PA, the cable comes from the back of
body. The KDA-PA is used to measure the pressure in soil and to monitor the behavior of embankments.
The KDB-PA is used to measure the pressure in earth retaining walls or the pressure on wall surfaces of structures.
10- Temperature Gauge
The temperature gauges use a special temperature gauge as an internal sensor device. It has a
waterproof structure and is suitable for being embedded in concrete or soil. Because it is designed
with the full bridge method, actual temperature can be measured using a measuring instrument that supports entry of initial values.
11- Concrete free water transducer Index
For quality control of concrete, seizing variation in the water content of concrete directly is rational and
very effective method. The concrete free water transducer continuously monitors water variation in the
concrete from fresh concrete to hardened concrete just after placement in electrical and non-destructive
way to let the user estimate the amount of concrete free water (vapor-possible water at 105°C). Thereby
curing state, the time of form removal and the time of surface finish can be judged. Also, the transducer
can be used for versatile applications such as the study on the hydration of concrete closely related to moisture in concrete, durability and maintenance control.
12- Caisson skin-friction meter
The is a transducer to measure skin friction bearing force with the ground acting on the wall of
concrete caisson. The transducer is installed so that the sensing area of the transducer faces
the caisson's wall and measures skin friction bearing force with the ground when settled and fixed.
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