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The good performance of seismically isolated structures during the 1995 Kobe earthquake persuaded structural engineers, isolator manufacturers and housing construction companies to undertake a cooperative research project to investigate the possibility of introducing the seismic isolation technology in Japan's private housing sector. As a part of this project, in this study, the seismic performance of a recently developed Friction Pendulum System (FPS) for houses is presented. In order to verify its behavior under recorded earthquake ground motions, 3-dimensional shaking table tests were conducted. A three-dimensional nonlinear model was used to simulate the experimentally recorded acceleration and displacement response. Experimental results showed that the FPS significantly reduced the acceleration response at both moderate and strong levels of input ground motion. The analytical model used in this study satisfactorily predicted the experimentally recorded acceleration and displacement response time histories.

After the Hanshin-Awaji Earthquake Disaster, the number of earthquake isolated buildings is increasing. Most of the base isolated buildings or structures are built on laminated rubber bearings in order to give them certain natural periods. This situation, however, also encourages structural engineers to research and develop nonrubber-type isolation systems such as linear motion bearing isolators and friction pendulum systems. It is considered that the nonrubber-type isolation systems can be applied to important industrial facilities, such as LNG tanks, boiler facilities and so on to refine their seismic reliabilities. In the device of the nonrubber-type isolation systems, the device which applied the sliding is especially noticed. However, when using nonrubber-type isolation systems with sliding in the open air circumstances, long term durability of the systems must be taken into account and it may be very difficult to maintain the friction coefficient of the system. In this study, the dynamic motion analysis and the experimental tests on the isolated structure mounted on four Friction Pendulum Bearing (FPB) Systems were carried out to investigate the performance of isolation due to the rotational motion which might be induced by the friction force difference in FPB system.

In this work a generalized hydrodynamic theory for the water flow into a mesoporous matrix from hydrophobized silica gel is suggested. Although we examine a fluid dynamics problem, i.e., the motion of the water-gas-solid contact line, motivation for such research derives from the investigation of a novel principle of mechanical energy dissipation, called colloidal damper. Similar to hydraulic damper, this absorber has a cylinder-piston structure, but oil is replaced by a colloid consisted of a mesoporous matrix and a lyophobic liquid. Here, the mesoporous matrix is from silica gel modified by linear chains of alkyldimethylchlorosilanes and water is the associated lyophobic liquid. Mainly, the colloidal damper energy loss can be explained by the dynamic contact angle hysteresis in advancing (liquid displaces gas) and receding (gas displaces liquid); such hysteresis occurs due to the geometrical and chemical heterogeneities of the solid surface. Measuring technique of the hysteresis loop is described. From experimental data one calculates the dissipated energy, damper efficiency and the damping coefficient versus the length of the grafted molecule on the silica gel surface. Experimental results are justified by the flow analysis. Generalized hydrodynamic theory means here that the basic structure of Navier-Stokes equations is kept, but in order to include the relation between macroscopic flow and molecular interactions, slip is allowed on the solid wall. Nano-pillar architecture of the silica gel hydrophobic coating is described. During adsorption, water penetrates the pore space by maintaining contact with the top of the coating molecules (region of -CH3 groups); after that, water is forced into and partially or totally fills the space between molecules (region of -CH2 groups); in such circumstances, at the release of the external pressure, desorption occurs. Mechanism of energy dissipation is discussed. Results obtained are useful for the appropriate design of the hydrophobic coating of a mesoporous matrix which is destined to colloidal damper use.