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The
term bearing is referred to as an elastomer block consisting
of one or more internal layers of Neoprene bonded to steel
laminates by the process of vulcanization. These bearings
are manufactured in accordance to IRC-83 (Part II) 1987 and
MOST 2000 specification.
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The shear modulus of the elastomeric bearing
is generally 1+20% Mpa. The physical properties
of elastomer are checked in accordance to ASTM-D 297 specification.
Fabrication of the bearing and the tolerance
limits is as per IRC 83 specification.
Finished bearings are generally tested after
seven days of its manufacture of the followings:
a. Elastic modulus value.
b. Shear modulus value.
c. Bond between the rubber and the laminates.
d. Ultimate strength in compression on the cut section.
Tests procedure and permissible limits are specified in IRC
83 (PartII) 1987 or UIC 772R specification, as applicable
to the project.
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Installation
and Postioning:
The bearings must be placed between true horizontal surfaces and at
true plan position of their control lines marked. Concrete surfaces
should be free from logical irregularities. For precast concrete superstructure
fixing of bearings may be done by epoxy application to interface.
Placing of bearing in the recess provided is advisable. Installation
of bearings one behind the other along the longitudinal centerline
of the bridge for the same group of bearings should not be allowed.
Since the bearings have different stiffness, different stiffness,
different sizes of bearings must not be placed next to each other.
Acceptance of bearings:
Acceptance of bearings shall be in accordance to the client's/administration
conditions applicable. The bearings shall be supplied with the test
results carried out during the manufacturing. In house test is also
carried out for shear modulus and elastic modulus on the final bearings.
Bearings shall be properly stored and handled during its transportation.
Test Facilities:
We at Tricon Polymer have all the apparatus/equipments for testing
of the properties of elastomer and raw material contents as per IRC
83 code. Designing and related R&D work is carried out at our works
from time to time. |
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