DESIGN AND PERFORMANCE OF HIGH DAMPING NATURAL RUBBER BASE-ISOLATORS

This paper discusses two current areas of research related to the design and performance of High Damping Natural Rubber (HDNR) isolators used in base-isolation of buildings and structures.(a) MRPRA has recently completed a UNIDO-funded project to erect a demonstration building protected from earthquakes using HDNR isolators. The building, a four-storey apartment block typical of low-cost public housing is sited in S.W. Java, Indonesia.The way in which HDNR bearings have been designed to meet requirements such as low horizontal stiffness, sufficient horizontal deflection capability and others is outlined.(b) The dynamic properties of HDNR compounds is presented. Their non-linear stress-strain behaviour is discussed and it is shown that despite this the use of linear models for these materials is adequate for assessing the performance of the isolated structure during earthquakes up to design level. A non-linear hysteretic model is also proposed.