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For
Japanese projects extensive testing was
performed on our range of isolators over
specific stresses and strains. This prequalification
testing eliminated prototype testing for
individual projects. Only QC testing is
done on production isolators which reduces
cost and shortens schedules by as much as
three months. |
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| Test Loop |
Isolators
are tested in pairs at our plant and singly
at laboratories such as at the University
of California, San Diego (UCSD). The test
machine applies a shear displacement and
axial load to the isolator. The loops shown
plot the shear force and lateral displacement
for the isolator and show the behavior of
the isolator for a range of strains up to
300%. |
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| Real Time Testing P200 |
DIS
has tested over 30 isolators at actual
earthquake velocities of up to 60
inches per second. The tests were
performed at the University of California,
San Diego. These tests validate the
performance of our isolators under
seismic conditions and provide detailed
velocity data for the isolators. Over
500 tests have been performed over
the last seven years on isolators
of up to 53.5 inches (1300 mm) in
diameter. |
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| Bearings for the Coronado
Bay Bridge were the first to be tested
at earthqake velocites at UCSD for Caltrans. |
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| Large Strain Testing |
DIS
has conducted extensive high strain
testing on isolators up to 53.5 inches
(1300 mm) in diameter. Isolators with
and without lead cores have been successfully
tested to over 400% shear strain.
Typical design shear strains are in
the 200 to 250% range. Other notable
large displacement tests performed
by DIS include a 45.5" (1200
mm) diameter isolator that was tested
to 45" (1140 mm) displacement
for the Berry Street Project in California.
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| The 41.5" (1100 mm)
diameter isolator shown here was tested
to 47 inches (1200 mm) shear displacement.
This bearing was tested as part of a
research program for an isolated dam
intake structure. |
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| 1-Mile Wear Test |
A
one-mile (1.6 km) wear test was performed
on DIS isolators at the SEES Lab,
SUNY at Buffalo. The tests were conducted
as part of prototype testing for the
new Woodrow Wilson Bridge over the
Potomac River in Maryland. This test
simulated the effect of a lifetime
of thermal expansions and contractions
of the bridge deck. The results pictured
here show that the isolator’s
properties were unchanged by this
extensive testing. |
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