The report contains the findings of a study on the mechanical behavior of unbonded fiber-reinforced bearings (FRB). Typical FRBs consist of several layers of rubber that are bonded to fiber reinforcing sheets. The purpose of the reinforcement is to prevent the rubber from bulging laterally under compressive load. The most important aspects of these bearings are (i) they do not have thick end plates; (ii) they are not bonded to the top and bottom support surfaces; and (iii) their reinforcements are very flexible. These aspects may seem to be design deficiencies, but they have the advantage of eliminating the presence of tensile stresses in the bearing by allowing it to roll off the supports when it is sheared. This reduces the typical bonding requirements. The weight and the cost of isolators is reduced by using fiber reinforcing, no end-plates, and no bonding to the support surfaces, offering a low-cost lightweight isolation system for developing countries. This work is the comparison between an approximated linear elastic theory and the outputs of finite element analyses.
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