Composed Isolation System Concept for Vibration Effects Mitigation …
475
Fig. 1 Schematically representation of composed isolation system on a bridge structure
The schematic representation of the composed isolation system assembly on a
bridge structure type is shown in Fig. 1.
Due to the disconnection made by means of composed isolation system, the foundation can move together with the ground while the superstructure has a different
vibration period that protects it from the ground acceleration amplitudes.
The insulator system allows movement up to the limit of the sliding bearing and
the elastic limit of the elastomeric system.
The displacements above this value are limited by the hydraulic dissipative system
[4].
3 Modeling Aspects for the Pendulum Rolling Isolation
System
The pendulum insulation system has concave geometry on the main sliding surface,
thus allowing relative displacement between the two structural elements where it is
mounted due to the activated degrees of freedom.
The translation movement in the plane is combined with a vertical lift, providing
a significant energy consumption required for lifting the superstructure, as well as
rotations that can occur simultaneously.
The mathematical modeling of the insulating pendulum supports is made taking
into account the radius of curvature of the sliding surface and the displacements that
may occur during the bearing operation.
The motion components are highlighted in Fig. 2 [5].
An imposed displacement (u) corresponds an angle (ϕ), as well as a vertical
elevation (h), from where the relations corresponding to the triangle formed by the
main rolling surface radius (R) and displacement (u) can be written [5]:
sin ϕ =
u
R
; cos φ =
R − h
R
(1)
475
Fig. 1 Schematically representation of composed isolation system on a bridge structure
The schematic representation of the composed isolation system assembly on a
bridge structure type is shown in Fig. 1.
Due to the disconnection made by means of composed isolation system, the foundation can move together with the ground while the superstructure has a different
vibration period that protects it from the ground acceleration amplitudes.
The insulator system allows movement up to the limit of the sliding bearing and
the elastic limit of the elastomeric system.
The displacements above this value are limited by the hydraulic dissipative system
[4].
3 Modeling Aspects for the Pendulum Rolling Isolation
System
The pendulum insulation system has concave geometry on the main sliding surface,
thus allowing relative displacement between the two structural elements where it is
mounted due to the activated degrees of freedom.
The translation movement in the plane is combined with a vertical lift, providing
a significant energy consumption required for lifting the superstructure, as well as
rotations that can occur simultaneously.
The mathematical modeling of the insulating pendulum supports is made taking
into account the radius of curvature of the sliding surface and the displacements that
may occur during the bearing operation.
The motion components are highlighted in Fig. 2 [5].
An imposed displacement (u) corresponds an angle (ϕ), as well as a vertical
elevation (h), from where the relations corresponding to the triangle formed by the
main rolling surface radius (R) and displacement (u) can be written [5]:
sin ϕ =
u
R
; cos φ =
R − h
R
(1)