DYNAMIC ANALYSIS OF THE BASE ISOLATED TUBULAR TALL BUILDING SYSTEM (LEADRUBBER BEARING) IN ETABS

In case of dynamic analysis of tall buildings, the various important dynamic characteristics of tall building namely, the natural frequency (ω, radians/second) or simply time period (T, seconds),lateral displacement, base shear and overturning moment of tall buildings using ETABS software. In this paper, an approximate procedure is generated to perform the seismic analysis of simple and tubular tall building system with base isolation (lead-rubber bearings) system and the outcome compared with the results obtained without base isolation (lead-rubber bearing) of tall buildings. Base isolation system is basically a passive control device which decouples the super structure from substructure resting ground motion by insinuating structural elements with low horizontal stiffness between the structure and foundation. This analysis of G+29 rigid joint plane RCC frame has for four cases. First case is simple RCC frame with fixed base and with base isolation (LRB), second case is simple tube RCC frame with fixed base and with base isolation (LRB), third case is tube in tube system RCC frame with fixed base and with base isolation (LRB) and fourth case is bundle tube system RCC frame with fixed base and with base isolation (LRB) .The effectiveness of base isolation in every cases is compared with simple frame and tubular system cases. This analysis is done by using ETABS software and for design purpose of base isolated system 1893:2002 (part 1) and for seismic design of isolated structures (F.Naeim and J.M.Kelly).