Rigidity-Plasticity-Viscosity: Can Electrorheological Dampers Protect Base-Isolated Structures From Near-Source Ground Motions?

Abstract

SUMMARYThe concept of seismic protection by lengthening the fundamental period of the structure has been implemented through a number of isolation systems. While flexible isolation systems can effectively protect structures from earthquakes containing high frequencies and sharp accelerations, they might amplify the response of the structure when subjected to rapid, long-period motions. In this case of long period excitations the stiff superstructure should be 'locked' to the ground, rather than be supported on flexible bearings. This paper shows through a comprehensive analytical study that a practical solution to this problem is to provide additional rigidity to the structure using a friction-type mechanism (rigid-plastic behaviour). The presence of friction-type forces reduce substantially the relative displacements of a singledegree-of-freedom structure by keeping accelerations at low levels; however, they are responsible for the presence of permanent displacements. Accordingly, the use of controllable fluid dampers is proposed and it is shown that they can be a practical solution to the problem. The response of a single-degree-of-freedom base-isolated structures is investigated, and the feasibility of a proposed electrorheological damper to deliver the required forces is discussed.1997 by John Wiley & Sons, Ltd.

Rocking Response and Stability Analysis of an Array of Free-Standing Columns Capped With a Free-Standing Rigid Beam

“…The early work of Veletsos et al [16] was followed by the papers of Hall et al [17], Makris [18], Makris and Chang [19], Alavi and Krawinkler [20] and more recently by the papers of Mavroeidis and Papageorgiou [21] and Vassiliou and Makris [22]. Physically realizable pulses can adequately describe the impulsive character of near-fault ground motions both qualitatively and quantitatively.…”

Inelastic Displacement Ratio Spectrum for Near-Fault Ground Motions

“…The categorization and analytical representation of near-fault earthquakes as well as the study of their effects on the seismic behavior of structures are very important research topics today. On e can mention here the works of Makris [8], Makris and Chung [9], Zhai et al, [10], Ruiz-Garcia [11] and Iervolino et al [12]. Although the development that has been accomplished so far, there is still a clear need to understand the behavior of structures subjected to near-source seismic ground motions.…”

Modeling, Simulation and Optimization of Electrorheological Fluids

“…The measurements have been performed using, e.g., confocal scanning laser microscopy (DASSANAYAKE et al [2000]), two-dimensional light scattering techniques (MARTIN et al [1998b]), and nuclear magnetic resonance imaging (UGAZ et al [1994]). The potential industrial applicability of electrorheological fluids in automotive applications (BAYER [1998], BUTZ and STRYK [2001], COULTER et al [1993], FILISKO [1995], GARG and ANDERSON [2003], GAVIN [2001], GAVIN et al [1996a,b], HARTSOCK et al [1991], HOPPE et al [2000], JANOCHA et al [1996], LORD [1996], PEEL et al [1996], SIMS et al [1999], STANWAY et al [1996], WEYENBERG et al [1996], ZHAO et al [2005]), aerospace applications (BERG and WELLSTEAD [1998], LOU et al [2001], WERELEY et al [2001]), food processing (DAUBERT et al [1998]), geophysics (MAKRIS [1999], XU et al [2000]), life sciences (KLEIN et al [2004], LIU et al [2005], MAVROIDIS et al [2001], MONKMANN et al [2003a,b], TAKASHIMA and SCHWAN [1985]), manufacturing (KIM et al [2003]), military applications (DEFENSE UPDATE [2004]), and nondestructive testing (MAVROIDIS [2002]) caused the US Department of Energy to issue a research assessment of electrorheological fluids (DOE [1993]) and popular scientific journals such as Science and Nature to publish overview articles (HALSEY [1992], WHITTLE and BULLOUGH [1992]). Further references covering various aspects of experimental work, modeling efforts, and applicat...…”