Geology Reference
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obstacle constituted by the aluminum windows.
Despite these strengths, it is not possible to exclude
the existence of micro- slips between the plates
that give the panel softness greater than that, which
is possible to calculate with a numerical model.
This hypothesis is confirmed if the experimen-
tal and numerical behaviors of the panel without
the internal aluminum plate are compared. In this
case, in fact, both for 20 kN and 40 kN panel, the
two curves are practically coincident, if we except
the non linear region (Figure 21). Therefore, the
difference existing in the behavior of the dissipater
can be recognized in the slippage between the
three different panels that constitute each device.
Finally, the two devices with the aluminum
plate have been compared considering the normal-
ized transversal load and top displacement, which
are the ratio of these quantities to the maximum
values measured for each panel. The result is
reported in Figure 22, showing that the two pan-
els have an identical behavior but at different load
and displacement levels. This fact demonstrates
the reliability of the design process used to estab-
lish the optimal values of the geometrical param-
eters of the device.
completed by a jet of concrete. At the ground
floor, two horizontal diagonals were fitted, made
with HEA160 profiles, while in the vertical planes
two HEA100 profiles diagonals on each floor
were installed (Figure 23c) to allow the mounting
of the dissipaters. In particular, the devices had
to be bolted to a plate, welded at the top of the
diagonals, and to the beam of the upper floor. In
this way, all rotations at the ends of the dissipat-
ers had been avoided.
The frame had been subjected to seven sig-
nals of natural earthquakes whose spectrum is
compatible with the one of Eurocode 8 for type
A ground. Tests had been performed scaling the
signals from 10% to 100%.
The test frame had been equipped with numer-
ous displacement and acceleration transducers. In
particular, the displacements at the base level and
at the first and second floors were measured. More-
over, a displacement transducer was positioned
in order to measure the transversal displacement
of each dissipating device. Finally, acceleration
in transversal and longitudinal directions was
measured at the first and at the second floors
(Diaferio et al. 2010). Due to the geometrical
configurations of the panel and of the frame, it
was not possible to mount a load cell to measure
the transversal shear load acting on each panel.
SHAKING-TABLE TESTS
Test Setup
Results of the Shaking-Table Tests
The device of 20 kN described in the previous
paragraphs was subjected to shaking table tests
(Ponzo et al. 2007, Gattulli et al. 2007, Serino et
al. 2007), installing four of them in a steel frame
in scale 2:3 (Figure 23). The frame had a 3m x
4m plane section and consisted of four HEB140
profile columns positioned at the corners and
IPE180 profile beams welded to columns. The
two levels were at an equal height of about 2 m,
while the columns emerged of 0.50 m from the
top floor.
The two floors consisted of A55/P600 section
corrugated sheets with a thickness of 0.8 mm and
Since it is fundamental to report in a plot the shear
load and the transversal displacement of each panel
in order to verify that effectively the device was
subjected to dissipating and hysteretic phenomena
during shaking-table tests, the shear load had been
evaluated by means of the acceleration measured
at each floor.
The model used at this purpose considers that
the inertia loads at each floor cause the transversal
loads acting on the panels. Assuming the floor as
a rigid body, its motion could be expressed by the
components of the accelerations of the centroid
G along the L and T directions (Figure 24a), al
G
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