Development of elastomeric bearing utilizing steel core with granular and polymer filler system for structures and bridges

Elastomeric bearing is the most common base isolation system for structure and bridges subjected to vibration and ground motion. To improve the energy dissipation performance of the base isolator, a lead core is implanted to enhance the damping and stiffness of elastomeric bearing. However, the most notable impact from lead-core rubber bearing is the adverse effect brought to human and environment by lead material. Therefore, in this study, an attempt has been made to innovate an elastomeric bearing equipped with steel core and filler system to improve the performance of bearing while posing minimal impact to human and environment. Two types of filler, namely sand and epoxy were implemented. The steel core was introduced to improve the shear stiffness of filler. The aim of this study is to develop an innovative elastomeric bearing that shows improvement in performance when compared to conventional elastomeric bearing and lead-core rubber bearing. Numerical models were developed for the proposed device according to prepared design details. Simulation was conducted using finite element method to evaluate the performance of proposed isolation and confirm the initial design details. Thereafter, the prototypes were manufactured and then experimentally tested under the combination of axial load and lateral displacement to assess the performance of propose base isolation devices. Effective stiffness and energy dissipation are used as the evaluation parameters, as they are commonly used to define the base isolator spring-dashpot model during structural analysis. The results from numerical analysis were deemed acceptable since the stiffness and damping component derived from it were within the acceptable error tolerance when compared against that derived from experimental result. Based on both numerical and experimental result, the proposed bearing systems were found possessing greater shear stiffness compared to the conventional elastomeric bearing and lead-core rubber bearing. Upon validation of finite element model, numerical parametric study was conducted based on the developed models. The purpose of this study is to evaluate the effect of material properties and loading conditions on the performance of proposed elastomeric bearing. Then, application case study was conducted by the mean of finite element analysis by integrating the base isolator into a G+5 building. From the analysis, the base isolators were able to elongate the vibration period of structure and reduces the peak spectral acceleration acting on the structure. They were proven effective in reducing the base shear acting on the structure, and eventually reduce the structural burden when ground motion occurs. In overall, the implementation of steel core and filler system provides a reliable improvement to the performance of conventional elastomeric bearing. Among the proposed innovations, fully filled sand system is the best for its tremendous improvement in bearing characteristics, as well as convenience during fabrication and maintenance.

Text TAN KAR CHUN - IR.pdf Download (1MB)

Actions (login required)

View Item