STUDY ON DESIGN AND STRUCTURAL RESPONSE COMPARISON OF ABUILDING STRUCTURE WITH BASEMENT WITH LEAD RUBBER BEARING SEISMICISOLATION LOCATED AT BASE AND AT STORY OF THE BUILDING

• Main Author: Samuel, Jeff
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/79480
• Institution: Institut Teknologi Bandung

Indonesia is a very earthquake-prone country. This is dangerous especially for critical structures that must operate after an earthquake. The use of seismic isolation is one of the many efforts to mitigate the damage due to earthquakes, in which the isolated structures are expected to undergo very minimum damage and can operate after big earthquakes. Seismic isolation is one of the passive control systems in the form of horizontally flexible but vertically stiff element that can “isolate” building structures above it, dissipate earthquake energy, and concentrate the deformation due to earthquake mostly on the seismic isolation system, whereby the superstructure above it undergoes minimum deformation and a reduction of earthquake force. At first, seismic isolation was developed to be places at base (base isolation system). As time goes by, an idea surfaces to put the seismic isolation on another story of the building, which is called the story isolation system. This system can enhance the seismic performance of the structure above and below the isolation system. But its dynamic behaviour is more complex compared to the base isolation system. This study conducts a comparation in design and structrual response of a low rise reinforced concrete hospital, consisting of a 2-story basement and 5-story upper structure, equipped with a Lead Rubber Bearing (LRB) isolation system. Three buildings are modeled, each with a different isolation plane. In the first model, isolation is at base (below the basement). In the second model, isolation is below the upper structure (between the basement and the upper structure). In the third model, isolation is located at the top of the upper structure (the fifth floor). Structural response is obtained by nonlinear time history analysis using seven pairs spectrally matched ground motions to each model. Supertructure is designed to behave elastically and nonlienar behaviour is expected only at the isolation system. Structural design is assessed by the LRB specification and reinforcement of seismic-resisting system. Structural response is assessed from the mode shape, base shear, roof acceleration, interstory drift, and energy dissipation of the LRB. It is found that placing the isolation system between the basement and the upperstructure gives the most optimum design and response, compared to the other two models.