Rubber bearing isolator with granular and polymer filler core and application on a building

Abstract

In the present study, a new core-and-filler system was proposed to use in elastomer bearings as a substitution to hazardous lead core while improving the performance of base isolators. The proposed system utilizes steel core and filler consists of either granular or polymer materials in relation to this proposal, both pure sand and epoxy are used as filler. Special design procedure for the proposed bearing was developed to determine the required dimension for elastomeric bearing under considered design loads according to the code of practice.The finite element model of the designed elastomeric bearing was developed to evaluate performance of the proposed bearings under design condition through nonlinear dynamic analysis. Then, parametric study was conducted to simulate various material properties and loading conditions that may occur during the manufacturing and service life of base isolation.Substantial improvement in performance of proposed bearing with core-and-filler system was observed in comparison to the lead rubber bearing. By reducing the volume of sand filler, the damping bearing of proposed sand and steel core mechanism can be improved. By manipulating the sand packing condition during manufacturing, improvement in term of effective stiffness is achievable. Trilinear constitutive curve for fully sand filled bearing revealed that, the increment in effective stiffness of bearing is higher for the shear strains more than 150%. Therefore, the core-and-filler system with full sand filler provides superior resistance against high shear strain in comparison to the lead-core rubber bearing, and achieve the purpose of limiting lateral displacement.Application of proposed elastomeric bearings in the 5-story building as base isolator has been proven the effectiveness and suitability of implementing bearing with core and fully filled sand and also with epoxy filler as alternative isolator to the lead core elastomer bearings.