Fluidic self-centering devices as elements of seismically resistant structures: Description, testing, modeling, and model validation

Fluidic self-centering devices operate on principles similar to those of fluid viscous dampers, but with additional capabilities to provide recentering force (or preload) and stiffness. The functions of preload, stiffness, and damping are entirely controlled by the physical properties, volume, and initial pressure of fluid, and the shaping of the orifices. They are characterized by compactness in comparison to the output force and stroke. They are proposed as self-centering bracing systems for buildings. This paper presents: (1) a description of the behavior of these devices that is on the basis of principles of mechanics, (2) models of behavior of the devices, (3) results of testing of a number of these devices to demonstrate their behavior, and (4) validation of the analytical models. The test results include those of two devices tested over a period of 22 years that demonstrate the stability of the properties of the devices.