Browsing by Subject "Settlement prediction"

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    Model uncertainties in "terzaghi and peck" methods for estimating settlement of footings on sand
    (2010) Akbas S.O.; Kulhawy F.H.
    The Terzaghi and Peck (1948) method was the first for predicting the settlement of footings on sand using standard penetration test blow counts (N values). Over the following 26 years, various modifications to this basic method were suggested. Herein, an extensive database of 426 settlement case histories is used to assess the model factors for this family of methods. The uncertainty of the model factors is characterized using the coefficient of variation. Considering the model factor as a random variable, the common "log-normality" assumption is investigated critically. The impact of model uncertainty on the reliability of settlement estimations is discussed, and criteria are given to assess their accuracy and conservatism. For settlement prediction, the uncertainty from the model factor is most influential. The results indicate a low accuracy for all of the methods considered. © 2010 ASCE.
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    The use of neural networks for the prediction of the settlement of pad footings on cohesionless soils based on standard penetration test
    (2013) Erzín Y.; Gul T.O.
    In this study, artificial neural networks (ANNs) were used to predict the settlement of pad footings on cohesionless soils based on standard penetration test. To achieve this, a computer programme was developed to calculate the settlement of pad footings from five traditional methods. The footing geometry (length and width), the footing embedment depth, Df, the bulk unit weight, γ, of the cohesionless soil, the footing applied pressure, Q, and corrected standard penetration test, Ncor, varied during the settlement analyses and the settlement value of each footing was calculated for each method. Then, an ANN model was developed for each traditional method to predict the settlement by using the results of the analyses. The settlement values predicted from the ANN model were compared with the settlement values calculated from the traditional method for each method. The predicted values were found to be quite close to the calculated values. It has been demonstrated that the ANN models developed can be used as an accurate and quick tool at the preliminary designing stage of pad footings on cohesionless soils without a need to perform any manual work such as using tables or charts. Sensitivity analyses were also performed to examine the relative importance of the factors affecting settlement prediction. According to the analyses, for each traditional method, Ncor is found to be the most important parameter while γ is found to be the least important parameter. © 2013 Techno-Press, Ltd.