Page 39 - DOUCE HYDRO 2013

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Dampers for
cable stays
P R O T E C T I O N S
AVE Series
he large global development of the technology for cable stays has created a
need for damping. Initial attempts to adapt commercial dampers failed to meet
the specific requirements of the bridge industry because they were not appro-
priate for bridges.
ouce-Hydro/Jarret Structures has developed a new generation of dampers in order to satisfy the
special requirement of damping cable stays. Because long-term vibrations due to wind and rain create
fatigue stress in the cables, the idea is to offer a very reliable unit which is able to dampen vibrations without
creating any additional stress to the structure.
T
D
Working Principle:
The Douce-Hydro’s/Jarret Structures’ Cable Stay Dampers (CSD) work on the principle that rapid flow of
viscous fluid through a narrow orifice or port, generates high resistance, which then dissipates a large amount
of energy. The energy is dissipated in heat. In order to avoid any possible leakage, the body of the unit is made
of a single stainless steel part. A piston head is moving through the viscous fluid, and the lamination of the
fluid creates the viscous damping.
The behaviour law of the viscous damper is F= C.Vα . According to the specifications required of a particular
application, Douce-Hydro/Jarret Structures can provide a value for the coefficient alpha which can range from
0.3 to 2.
Viscous dampers for cable stays (CSD)