An Efficient Horizontal Stiffness Solution for Unbonded-Frebs
Unbonded-Fiber Reinforced Elastomeric Bearings (U-FREBs) area new type of elastomeric bearings that are placed between their top and bottom supports without any bonding.When subjected to lateral loads, U-FREBs exhibit rollover deformation which means that their top and bottom faces roll off the contact supports. As such, the lateral response characteristics of U-FREBs is different than conventional steel reinforced elastomeric bearings that are fixed to their top and bottom supports. The literature includes a set of analytical models for horizontal stiffness evaluation of U-FREBs.However, thesemodels are not so effectiveto provide accurate estimation for a wide range of bearing physical dimensions. This paper presents a finite element analysis calibrated analytical model for horizontal stiffness evaluation of U-FREBs.The model has been calibrated based on the results of finite element analysis of a large group of bearings of different physical dimensions. The accuracy of the presented model is preserved for bearings of different shape factors.
Keywords - Seismic Isolators; Fiber Reinforced Elastomeric Bearing; Unbounded Application; Horizontal Stiffness; Finite Element Analysis; Shape Factor; Aspect Ratio