STUDY ON STIFFNESS, DEFORMATION AND ULTIMATE CHARACTERISTICS OF BASE-ISOLATED RUBBER BEARINGS : Horizontal and vertical characteristics under shear deformation

Abstract

In this paper, we are examining from both sides of theory and experiment about the horizontal and the vertical mechanical characteristics of Base-isolated Rubber Bearings, from tensile to high-compressive stress condition (-20〜300kg/cm^2). First of all, we propose the theoretical expression of the horizontal stiffness under tensile condition based on the Haringx's theory. Next, we propose the theoretical expression of the total compressive (or the total tensile) stiffness under shear deformation, by solving eqation of the strain energy of Rubber Bearings. In addition, we carried out experiments using small and actual size of Rubber Bearings those diameters were 7, 16, 25, 50 and 80cm respectively. The results of experiments show that we can express the horizontal stiffness under tensile stress, and the vertical deformation under shear deformation, by these proposing expressions. After all, we get the relation between compressive (or tensile) stress and ultimate shear strain by using the proposing expressions of the total compressive (or the total tensile) stiffness.