"The objective of this project was to evaluate the interaction between the shear modulus of steel reinforced neoprene bearing pads and shear strain rate. The following interactions related to variations in the shear modulus were investigated for pads with various shape factors: product approval strain rates vs. short-term field strain rates, short-term field strain rates vs. long-term field strain rates, reduction in shear modulus due to load cycles, and effects of compressive stress"--Technical report documentation page.
My involvement in the use of natural rubber as a method for the protec 1976. At that time, tion of buildings against earthquake attack began in I was working on the development of energy-dissipating devices for the same purpose and had developed and tested a device that was even tually used in a stepping-bridge structure, this being a form of partial isolation. It became clear to me that in order to use these energy devices for the earthquake protection of buildings, it would be best to combine them with an isolation system which would give them the large displace ments needed to develop sufficient hysteresis. At this appropriate point in time, I was approached by Dr. C. J. Derham, then of the Malaysian Rubber Producers' Research Association (MRPRA), who asked if I was interested in looking at the possibility of conducting shaking table tests at the Earthquake Simulator Laboratory to see to what extent natural rubber bearings could be used to protect buildings from earthquakes. Very soon after this meeting, we were able to do such a test using a 20-ton model and hand-made isolators. The eady tests were very promising. Accordingly, a further set of tests was done with a more realistic five storey model weighing 40 tons with bearings that were commercially made. In both of the test series, the isolators were used both alone and with a number of different types of energy-dissipating devices to en hance damping.
Widely used in civil, mechanical and automotive engineering since the early 1980s, multilayer rubber bearings have been used as seismic isolation devices for buildings in highly seismic areas in many countries. Their appeal in these applications comes from their ability to provide a component with high stiffness in one direction with high flexibility in one or more orthogonal directions. This combination of vertical stiffness with horizontal flexibility, achieved by reinforcing the rubber by thin steel shims perpendicular to the vertical load, enables them to be used as seismic and vibration isolators for machinery, buildings and bridges. Mechanics of Rubber Bearings for Seismic and Vibration Isolation collates the most important information on the mechanics of multilayer rubber bearings. It explores a unique and comprehensive combination of relevant topics, covering all prerequisite fundamental theory and providing a number of closed-form solutions to various boundary value problems as well as a comprehensive historical overview on the use of isolation. Many of the results presented in the book are new and are essential for a proper understanding of the behavior of these bearings and for the design and analysis of vibration or seismic isolation systems. The advantages afforded by adopting these natural rubber systems is clearly explained to designers and users of this technology, bringing into focus the design and specification of bearings for buildings, bridges and industrial structures. This comprehensive book: includes state of the art, as yet unpublished research along with all required fundamental concepts; is authored by world-leading experts with over 40 years of combined experience on seismic isolation and the behavior of multilayer rubber bearings; is accompanied by a website at www.wiley.com/go/kelly The concise approach of Mechanics of Rubber Bearings for Seismic and Vibration Isolation forms an invaluable resource for graduate students and researchers/practitioners in structural and mechanical engineering departments, in particular those working in seismic and vibration isolation.
The purpose of this study was to analyze elastomeric bearing performance on the basis of elastomer hardness, shape factor, reinforcing shim orientation, degree of taper and compressive stress level with the goal of developing a simple design procedure which standardizes as many of those parameters as possible. Particular emphasis was placed on comparing the behavior of flat and tapered bearings. Experimentation included shear, compressive, and rotational stiffness tests, shear and compression fatigue loading, long-term compressive loading, and tests to determine compressive stress limits.
