Considerations on operating principle of fluid viscous dissipation model used for bridge seismic isolation
Journal Title: Romanian Journal of Acoustics and Vibration - Year 2014, Vol 11, Issue 2
Abstract
The main concern of structural engineers is related to capabilities to ensure structure stability during seismic actions. Therefore different mechanical systems have been designed which can be attached to structures in order to change their behavior during earthquakes. This paper presents a special device that can be mounted at bridge or viaduct structures aiming to obtain an improved behavior of these structures during earthquake actions. The special device is presented as a hydraulic system that can assure dissipation of earthquake input energy. Along with the sliding and elastomeric bearings, the fluid viscous device may form a complete safety system capable to protect the isolated structure from the earthquake destructive actions. The fluid viscous system is composed of a cylinder with piston which can be translated inside the cylinder through the hydraulic fluid due to the orifices formed in the piston head. The fluid used for these special devices is typically mineral or silicone oil. Usually viscous fluid devices are connecting the bridge foundation and superstructure, so that in the occurrence of an earthquake, the piston is forced to move through the fluid medium inside the cylinder. Due to the low value of the passage orifices diameter the displacement is strongly restrained. Because of this resistance achieved at the hydraulic device ends a considerable amount of energy from the total earthquake energy is taken over, dissipated and converted into caloric energy due to internal friction forces, being after transferred to the external environment through the cylinder walls. In this paper it is presented a model of viscous fluid dissipation device that can be used in isolation of bridge or viaduct structural types against seismic activities. A three-dimensional assembly model was conducted at a reduced scale for the device equipped with flanges for clamping to the structural elements which has been analyzed in terms of operation principle using ANSYS FLOWIZARD program.
Authors and Affiliations
Scheaua FANEL
Keywords
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