Fuzzy Logic Models for Seismic Damage Analysis and Prediction

This paper extends some authors’ previous approaches to models and methods based on fuzzy sets and fuzzy logic, for the seismic fragility updating and seismic damage evaluation, in their contributions to the IFIP 8 Conference (Krakow – 1998), SMiRT 16 (Washington DC – 2001) and SMiRT 18 (Beijing – 2005) Conferences. A short survey of such earlier and more recent proposals for applying fuzzy concepts and methods in structural reliability and seismic damage evaluation is given in the Introduction. Basic concepts related to fuzzy sets and fuzzy logic inference rules follow in the next section. Certain applications of models based on fuzzy logic to the seismic damage assessment of RC structures are presented in the third section. The fuzzy rule bases are involved in the estimation of a damage index corresponding to the damage state of the structure by means of a de-fuzzification process. It is also discussed a fuzzy logic based method (due to S.K. Deb and G.S. Kumar) for estimating the level of seismically induced damages by use of certain damage indices. Other recent models based on fuzzy logic for the seismic damage assessment and control are also discussed, with emphasis on the fuzzification / defuzzification techniques. Applications to the seismic damage assessment of RC structures by means of fuzzy logic models are approached next.