Seismic Analysis of Bridges with nonlinear FVDs using effective damping

Fluid viscous dampers (FVDs) are passive energy dissipation devices that can reduce the dynamic response of a structure when subjected to seismic forces, and have been used in the last years in civil engineering structures, such as for damping of the longitudinal vibration of bridges under seismic actions.
With the use of FVDs it is possible to add high damping values to structures, with values of the effective damping ratio ξ up to 20-30 %, avoiding the need to develop plastic hinges to dissipate energy [3]. Using FVDs on a bridge it is possible to reduce its longitudinal displacement due to seismic actions, and therefore the maximum forces in the bridge’s structural members that depend on it.
When compared to other passive energy dissipation devices, such as hysteretic dampers, friction dampers or viscoelastic dampers, FVDs have the advantage of not adding stiffness to the structures to which they are applied and not having any residual deformation after the seismic event [3]. Figure 1.1 shows a set of compression-only nonlinear FVDs in a bridge’s abutment, parallel to its longitudinal axis.
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