Abstract
The paper discusses the use of rubber bearings in base isolated structures. In Japan alone there are likely to be 100 base-isolated buildings completed by the end of 1994 all of which will be on rubber bearings [Ref 1.2]. A distinction is drawn between the use of rubber bearings in bridges where they are subject to both the fatigue of traffic loading and diurnal temperature movements throughout their life, and their use in buildings where the loading is comparatively static until severe earthquake shaking occurs, which at a particular location is not likely to occur more than about once a century. Vertical load capacity and characteristics of vertical deflection in relation to rubber layer thickness and instability are discussed. Shear stiffness and deflection characteristics are outlined together with methods used for providing damping, including damping in lead-rubber bearings. The design of the high-stability aseismic bearing for loads of 1 tonne upwards is discussed in relation to its stability characteristics. It is suggested that tensile forces should be permitted in the short-term loading induced by earthquakes and this is confirmed by current Japanese practice in using fully bonded bearings. The development of self-damping rubber bearings is discussed.
Highlights
There has been a rapid expansion of the use of rubber bearings for the base isolation of structures against earthquake attack
The most significant advance in damping came in the 1970s with the introduction of a lead plug down the centre of the bearing following research work at the DSIR in New Zealand (Figures 1 & 13) This method has been accepted worldwide and buildings and bridges have been constructed in New Zealand, California and Japan using the method, using bearings manufactured under licence in these two latter countries
The use of steel dampers in Japan loaded into the plastic range in bending, has sparked off a continuation of testing work, which was initiated at the DSIR in New Zealand from 1970 with the main interest in Japan being the performance of round mildsteel bars, either manufactured as straights or bents, often fixed at one end and loaded as a cantilever at the other through a sliding ball joint which allows for the increase in length required as the structure deflects laterally
Summary
The paper discusses the use of rubber bearings in base isolated structures. In Japan alone there are likely to be 100 base-isolated buildings completed by the end of 1994 all of which will be on rubber bearings [Ref 1.2). A distinction is drawn between the use of rubber bearings in bridges where they are subject to both the fatigue of traffic loading and diurnal temperature movements throughout their life, and their use in buildings where the loading is comparatively static until severe earthquake shaking occurs, which at a particular location is not likely to occur more than about once a century. Vertical load capacity and characteristics of vertical deflection in relation to rubber layer thickness and instability are discussed. Shear stiffness and deflection characteristics are outlined together with methods used for providing damping, including damping in lead-rubber bearings.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Bulletin of the New Zealand Society for Earthquake Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
