Abstract

Abstract: Ring springs are frictional devices consisting of inner and outer ring elements assembled to form a spring stack.External load applied to the spring produces sliding action across mating ring interfaces. Large amounts of energy, asmuch as 60-70% of the total cycle energy, may be absorbed in overcoming frictional forces.This thesis details the characteristics and dynamic behaviour of ring spring systems and describes the design and testingof a seismic isolation system that uses ring springs.Initially the characteristics and fundamental dynamic behaviour ofsingle-degree-of-freedom mass/ring spring systems are studied. This study uses a model based upon the non-linearforce/deflection characteristics of the ring spring. A prototype ring spring cartridge that enables dynamic inputs to beapplied to a ring spring was then designed and subjected to short duration shock excitation. Experimental results arecompared with those given by computer simulation and are seen to be in good agreement.Ring springs have been identified as suitable devices for use in earthquake-resistant structures. A particularly attractivecandidate for use of ring springs is in protecting columnar structures during earthquakes. To enable further study, apivotal rocking seismic isolation system was developed. So that computational analyses of these systems could beundertaken, the ring spring model has been incorporated within the computer program RUAUMOKO. Dynamic analysesusing RUAUMOKO show that pivotal rocking isolation systems can significantly reduce structural loads during shortperiod type earthquakes