On the Influence of Pure sliding Bases, Considering Variable Frictional Coefficient and Vertical Earthquake

The effect of vertical earthquake component is studied here on the behavior of sliding foundations. Regarding complication of the problem and in order to focus well on the main subject, the superstructure is considered as a rigid block, which can be a representative of low masonry buildings. Recent researches show that coefficient of friction is not constant, but depends on instantaneous frequency and amplitude of the vertical vibration which normally change during the earthquakes. These instantaneous parameters can be calculated by WAVELET transforms. Both horizontal and vertical components of earthquake as well as the variation of frictional coefficient are considered in the analyses of this study. The results for five different earthquake records show that the applied acceleration of the block rises by considering the vertical earthquake, however variable frictional coefficient, compared with the constant one, decreases the acceleration. Both vertical earthquake and variation in frictional coefficient raise the sliding of the block in most cases.