Fuzzy rule based seismic risk assessment of one-story precast industrial buildings

Efficient tools capable of using uncertain data to produce fast and approximate results are more practical in rapid decision-making applications when compared to conventional methods. From this point of view, this study introduces a risk assessment model for one-story precast industrial buildings by fuzzy logic which builds a bridge between uncertainty and precision. The input, output and relations of the fuzzy based risk assessment model(FBRAM) were determined by reference buildings. The Monte Carlo simulation method was used to handle uncertainties associated with the structural characteristics of the reference buildings. Section dimension, longitudinal reinforcement ratio, column height related to building elevation, confinement ratio and seismic hazard are regarded as input and the plastic demand ratio is considered as the output parameter by the mathematical formulation of strength and deformation capacity of the buildings. The supervised learning method was used to determine the membership function of fuzzy sets. Fuzzy rules of FBRAM were constructed from Monte Carlo simulation by mapping of inputs and output. FBRAM was evaluated by a group of simulated buildings and two existing precast industrial buildings. Comparisons have shown significant agreement with analytical model results in both cases. Consequently, it is anticipated that the proposed model can be used for the seismic risk mitigation of precast buildings.     

A statistical assessment on global drift ratio demands of mid-rise RC buildings using code-compatible real ground motion records

Over the past 20 years, significant socio-economic losses have been encountered in Turkey due to several moderate to large earthquakes. The studies published after the earthquakes concurringly emphasized that multistory reinforced concrete (RC) buildings, mostly 3–7 story ones, collapsed or were heavily damaged as a result of inadequate seismic performance. Global drift ratio demands are mostly used as a representative quantity for determining the behavior of structures when subjected to earthquakes. In this study, three representative mid-rise RC buildings are analyzed by nonlinear time history analysis using code-compatible real ground motion record sets and the calculated global drift ratio demands of these buildings are statistically evaluated. Ground motion record sets compatible with the design spectrum defined for local soil classes in the Turkish Earthquake Code (TEC-2007) are used for the analyses. In order to evaluate the effect of the number of ground motions on drift ratio demands, five different ground motion record sets with 7, 11 and 15 ground motion records are used separately for each local soil class. Results of this study indicate that (1) the dispersion of global drift ratio demands calculated for individual ground motion records in record sets is high, (2) local soil class has no significant effect on dispersion. However, dispersion increases in a direct proportion to the number of ground motion records in a record set, (3) the mean of global drift ratio demands calculated for different ground motion record sets may differ although they are compatible with the same design spectrum, (4) the mean of the drift demands obtained from different ground motion record sets compatible with a particular design spectrum can be accepted as simply random samples of the same population at 95% confidence level.