Douce-Hydro/Jarret Structures devices use special viscoelastic silicone-based fluids.
Industrially proven by over 50 years’ experience, our technology is based on the characteristics of these viscoelastic fluids.
Lhe Douce-Hydro/Jarret Structures shock absorbers are designed to dissipate seismic or dynamic energy on a structure. The ASR (FVD) series dampers work in tension and compression. These dampers reduce longitudinal and transverse or vertical displacements of a deck. They can be installed on various types of structure, for example longitudinally between the deck and the abutment, or transversely between the deck and the piers of a bridge. They can also be installed in a building to provide bracing or insulation at the base. The seismic energy absorbed is dissipated by the damper, and not in the concrete or steel structures.
PROTECTION OF BUILDINGS
Base insulation
Operating principle :
Base isolation is a solution for protecting individual buildings or small blocks of flats. This system is in fact a combination of insulators (elastomer pads) and shock absorbers. Isolators reduce forces, but increase displacements. Dampers reduce displacement by dissipating energy. This combination protects the building structure. This reduces the forces and displacements transmitted to the foundations.
Inter-storey bracing
Application to high-rise buildings
Series combination of RAP (PSD) + prestressed cables or RAP (PSD) + transmitters or ASR (FVD)
Can be installed on existing buildings Limited dimensions
Bracing cable insulation system
(CBIST)
Operating principle :
The aim of the innovative Cable Brace Isolation System Technology is to dissipate energy in the event of an earthquake using prestressed cables and tension dampers.
(CBIST)
BRIDGE / VIADUC
Sccording to the type of construction (bridge, viaduct), Douce-Hydro/Jarret Structures designs shock absorbers that dissipate a significant part of the energy and limit the movement of the deck so as not to damage the abutments and structure.
Special shock absorbers for railway viaducts
Douce-Hydro/Jarret Structures has developed a special unit designed to react in three different ways:
Effortless movement at low speeds
Blocking during train braking, behavior similar to that of a blocking shock absorber (AB)
Energy absorption during blockage (earthquake), shock absorber-like behavior (ASR)
These devices are designed to be used in conjunction with spherical pot fixtures.
PRELOADED SHOCK ABSORBER SPRINGS
A prestressed damper spring (PSD) is a device designed to dissipate energy on structures such as bridges. The PSD reduces longitudinal and transverse displacement of the deck. Douce-Hydro/Jarret Structures offers different types of PSD: working in tension and compression, or working only in compression. Douce-Hydro/Jarret Structures can install a compression-type RAP longitudinally between the deck and the abutment, or a tension/compression-type RAP in a transverse position between the deck and the piers. The RAP acts like a key, with the ability to regenerate automatically after a dynamic event. Energy is dissipated in the RAP and does not affect the steel or concrete structure. Depending on their positioning, the devices can absorb transverse and longitudinal seismic displacements, while allowing longitudinal displacements caused by creep shrinkage and thermal expansion or contraction.
Shock absorbers :
Applications :
Blocking dampers, also known as dynamic connectors or force transmitters, can be used on steel and concrete structures. They are installed on bridges with pre-stressed decks to eliminate large deck displacements during earthquakes. For other civil engineering structures such as buildings, blocking dampers can provide additional rigidity to the structure. They can also be used to reinforce adjacent buildings in the event of a seismic event.
Shock absorbers for guy wires
The worldwide development of cable-stayed cable technology created a need for shock absorbers. Early attempts to adapt commercially available dampers failed to meet the specific requirements of the bridge and viaduct industry, because these dampers were not adapted to these structures.
Douce-Hydro/Jarret Structures has developed a new generation of shock absorbers to meet the special damping requirements of guyed cables. As long-term vibrations due to wind and rain create fatigue stress in the cables, the idea is to offer a highly reliable unit capable of damping vibrations without creating additional stress in the structure.
Operating principle :
Shock absorbers for guy wires work on the principle that a rapid flow of viscous fluid through a narrow orifice generates a high level of resistance, enabling a large amount of energy to be dissipated. This dissipated energy is converted into heat. To prevent leakage, the unit’s body is made of one-piece stainless steel. A piston head moves through the viscous fluid, and lamination of the fluid creates damping.
The law of behavior of the viscoelastic damper is: F = C.Vα. Depending on the specifications of a particular application, Douce-Hydro/Jarret Structures can vary the alpha coefficient between 0.3 and 2.
