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novel sliding elements during their short time
contact of the sliding plates taken into account.
The main parameter of the three TLCGD (diago-
nally orientated TLCGD1 and TLCGD2, z-par-
allel TLCGD3) obtained by Den Hartog's optimal
tuning formulas and their transformations result
for the effective lengths of the fluid columns
L
eff
1
damping of the base isolated building with
TLCGD installed is illustrated in Figure 5. The
weighed sum of the building response, again
modal generalized coordinates are used in
S z
i S
∑
, is reduced tremendously at the reso-
nant peaks for a critical angle of earthquake in-
cidence,
α
=
125
.
°
=
. m
,
L
eff
2
11 7
=
. m
,
L
eff
3
14 3
=
. m
,
9 0
and the modal mass ratios
µ
1
=
. %
,
2 25
APPLICATION TO LONG SPAN
BRIDGES AND FOR THE
CANTILEVER METHOD OF BRIDGE
CONSTRUCTION
=
. %
,
µ
3
1 72
=
. %
: optimal absorber
0 6
µ
2
frequencies
f
A
1
=
.
0 486
Hz
,
f
A
2
=
.
0 493
Hz
,
=
. Hz
, and optimal linear damping
coefficients
ζ
A
1
f
A
3
0 814
=
. %
,
ζ
A
2
6 51
=
. %
,
6 02
Long span bridges with low structural damping
generally perform coupled, oblique bending and
torsional vibrations. Depending on the source of
excitation, e.g. traffic flow, trains moving sinu-
soidally on the rails, critical gusty winds or even
pedestrians, and seismic forcing, the bridge vibra-
tions can increase up to critical levels. Especially
=
. %
. Because of the extremely low
frequencies of the base isolated building, the gas
compression might be close to isothermal condi-
tions. A subsequent state space optimization
quickly renders the optimal natural frequencies
slightly lowered and the optimal linearized damp-
ing coefficients reduced. The increase in effective
ζ
A
3
3 97
Figure 5. Weighed sum of amplitude response function (expressed in generalized modal coordinates)
for the base isolated building with and without TLCGD installed
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