An experimental study on SEISMIC response of a two-storey structure having cylindrical base isolation system using model test equipment

The primary cause of damage during earthquake was the structures response to ground motion. A building directly built on the ground moves and accelerates with it. When strong earthquakes happen, the structure deforms excessively and worse, collapses. To solve this problem, a new design approach called base isolation was formulated separating the superstructure from the ground to minimize earthquake-induced vibration.
This study was mainly concerned with providing a brief knowledge of the performance of base isolation buildings during ground excitation through experimentation. It aims to show the effectiveness of base isolation system in reducing the ground acceleration experienced by the structure. To prove this claim, the dynamic responses of a building fixed to the ground with one which was separated by base isolator were compared and analyzed.
The structural model and the shaking table used in the experimental study were designed, built and further improved to be able to arrive at precise results. Two major types of tests were carried out to obtain the data needed. Free vibration test was performed to get the natural period of vibration of the model structure. Forced vibration test was done to evaluate the horizontal displacement of the isolated and the non-isolated building model. Stiffness of the model structure and the isolation used were also determined.
Data obtained were tabulated, graphed and analyzed with the aid of Microsoft Excel 2010. The building?s natural period of vibration and the structure?s dynamic response with fixed support system were verified theoretically. It was proven that base isolation system minimizes the response amplitude, specifically the horizontal displacement of the structure.
The accuracy of experimental result was dependent on the reliability of the structural model and shaking table as well as the execution of the different tests. Errors cannot be avoided. Some recommendations for the improvement of the structural model and operation of the equipment were suggested to acquire more accurate result.

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