The use of approximate entropy in the generation of a seismic performance index for wooden buildings

The main purpose of this paper is to present an alternative performance index using approximate entropy. We focus our attention on a correlation with the complexity of vibration as an indication of potential damage in the building. When there is abnormality in human cells, the vibration of these cells becomes irregular. Using this as inspiration, the complexity of vibrations in a wooden building will be used as a performance index. In this study, we chose Approximate Entropy to represent this complexity. A series of experiments for two wooden houses was conducted. Those two houses were put on the vibration table called 'E-defense', and excited by a white noise in various levels and by a recorded earthquake motion. The value of Approximate Entropy and natural frequency were calculated from the acceleration response of the houses. It is indicated that Approximate Entropy has a good correlation with natural frequencies which may indicate a correlation with damage.