Analysis of Structures with Seismic Rubber Base Isolators and Viscoelastic Damper Distribution in Areas of High Earthquake Hazard Risk

Abstract

Earthquakes exert significant forces on structures, necessitating meticulous design to ensure resilience against these seismic forces. In regions with high seismic hazard risk, various techniques and materials have been developed to safely dissipate the energy and forces induced by seismic activity. Among the widely recognised materials for protecting structures from seismic forces are lead rubber bearing(LRB) isolators and viscoelastic dampers(VED), which have been utilised in this study. In the scope of this research, reinforced concrete frame structures with varying structure heights were designed according to the TS500 regulations. Multiple models were developed for three different structure heights (6, 8, and 12 storeys), and for each, under three distinct support and damping conditions: fixed support, base isolated with LRB isolators, and base isolated with LRB isolators combined with different distributions of VEDs through story levels. These structures were analysed using the CSI SAP2000 structural analysis programme. Non-linear Time-History dynamic analysis was performed on these models using real earthquake parameters from a near-fault seismic event (Düzce, 12th of November 1999). The relative storey displacements, the displacement at the top storey and storey shear forces were compared. The soil parameters was defined into the non-linear analyses to achieve results that closely represent the actual behaviour of the structure during an earthquake. The primary aim of this thesis is to compare the analytical results of structures with three different support and damping conditions with different structure heights and to demonstrate the most notable improvements. The method, contribution of seismic LRB isolators and distribution of VEDs were examined based on the analytical behavioural results of the structures under seismic forces. The utilisation of LRB isolators resulted in increased structural periods, reduced story shear forces, and diminished story displacements, thereby enhancing the safety of the structures. The use of VED addressed the potential issues associated with these increased periods, particularly in higher structures. The findings of this study reveal that structures equipped with a suitable distribution of VEDs and LRB isolators exhibited superior seismic performance compared to traditional fixed-based structures.