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Model Uncertainties in Foundation Design

Geotechnical Engineering in the Era of Industry 4.0 Industry 4.0: Force of Change State of Civil Engineering Review of Geotechnical Engineering History of Geotechnical Engineering Art of Geotechnical Engineering Evolution of Design and Risk Management Towards Digital Transformation Role of Geotechnical Data Data Rich or Data Poor?Univariate/Multivariate Soil/Rock Databases Geotechnical Performance Databases Characteristics of Geotechnical Data Value of Geotechnical Data Scope and Organization References Evaluation and Incorporation of Uncertainties in Geotechnical Engineering Sources of Uncertainty Statistical Analysis Data Outliers Descriptive and Inferential Statistics Frequentist and Bayesian Inference Aleatory Uncertainty Epistemic Uncertainty Model Uncertainty Model Factor Removal of Statistical Dependency Limitations Bivariate Correlated Model Factors Transformation Uncertainty Statistical Uncertainty Measurement Error Incorporation of Uncertainties in Geotechnical Design Overview Reliability-Based Design Limit State Design Reliability Theory Load and Resistance Factor Design (LRFD) Calibration General Principle Ultimate Limit State (ULS)Serviceability Limit State (SLS)Conclusions References Basics in Foundation Engineering Introduction Types of Foundations Basic Principles for Foundation Design Information Requirements and Foundation Design Process General Considerations Foundation Selection – the Five S’s Permissible Foundation Movement Guidelines on Limiting Settlement Site-Specific Assessment Determination of Bearing Pressure Types of Foundation Load Tests Static Load Test (SLT)Head-Down Load Test Bi-directional SLT Rapid Load Test (RLT)Dynamic Load Test (DLT)Methods to Interpret SLTs Interpretation Methods for Compression Tests Movement Limitation Graphical Construction Mathematical Modelling Comparison of Interpretation Methods Effect of Extrapolation Summary References Evaluation of Design Methods for Shallow Foundations Type and Selection of Shallow Foundations Shallow Foundation Type Selection and Application of Shallow Foundations General Considerations in Shallow Foundation Design ULS: Bearing Capacity Foundations under Axial Compression Modes of Bearing Capacity Failure Category 2 Methods: Bearing Capacity Theory General Formula Failure Envelope for Combined Loading of Shallow Foundations Foundations under Uplift Failure Mechanisms Calculation Methods for Uplift Capacity IEEE (2001) Method Meyerhof and Adams (1968) Method SLS: Settlement Databases for Shallow Foundations Overview NUS/ShalFound/919 Model Uncertainty in Shallow Foundation Design Background Capacity and Settlement Model Factors Capacity Model Statistics Dependency of the Capacity Model Factor on Footing Width Settlement Model Statistics Probabilistic Models for Model Factors and Hyperbolic Parameters LRFD Calibration ULS Resistance Factor SLS Resistance Factor Conclusions References Evaluation of Design Methods for Offshore Spudcans in Layered Soil Introduction Jack-Up Rig and Spudcan Foundation Difference between Conventional Shallow Foundation and Spudcan Vertical Bearing Capacity of Spudcan in a Single Layer Penetration in Clay Penetration in Silica Sand Punch-Through Failure Calculation of Punch-Through Capacity Sand-Over-Clay Calculation Methods in ISO 19905-1:2016 Load Spread Model Punching Shear Method Initial Stress-Dependent Models Okamura et al. (1998) Method Teh (2007) Method Failure Stress-Dependent Models Lee et al. (2013b) Method Hu et al. (2014a) Method Ullah et al. (2017a) Method Incorporation of Stress-Level Effect Stiff-Over-Soft Clays Calculation Method in ISO 19905-1:2016 Calculation Methods in Zheng et al. (2016)Punch-Through Depth d p Semi-empirical Method Improved ISO 19905-1:2016 Method Foundation Punch-Through Centrifuge Test Databases Shallow Foundations in Sand-Over-Clay: NUS/ShalFound/Punch-Through/31 Spudcan in Layered Soil: NUS/Spudcan/Punch-Through/212 Multi-layer Clays with Sand Sand-Over-Clay Clay with Sand Multi-layer Clays Stiff-Over-Soft Clays Multi-layer Clays Model Uncertainty in Punch-Through Capacity Calculation Scatter Plot Analyses /. I Load Spread and Punching Shear Models Okamura et al.’s (1998) Method Ullah et al.’s (2017a) Method Verification of the Multi-layer Soil Profile Dependency of the Model Factor on Input Parameters Further Verification by Numerical Analyses Conclusions References Evaluation of Design Methods for Driven Piles and Drilled Shafts Deep Foundation Alternatives Driven Piles Drilled Shafts Micropiles Continuous Flight Auger (CFA) Piles Science and Empiricism in Pile Design Basic Load-Movement Behaviour Enhanced Understanding of Displacement Pile Behaviour I Complex Soil Stress-Strain History Time Dependency of Pile Capacity (Setup)Residual Load Critical Depth Plugging of Open Pile Sections Direction of Loading Rock-Socket Behaviour Static Analysis Methods for Pile Axial Capacity Basic Approach Category 1 Methods Empirical Correlations with SPT and CPT Data Empirical Correlations with Rock Strength Pile Driving Formulas Category 2 Methods Total Stress Analysis Effective Stress Analysis λ-Method Settlement of Single Pile Foundations Category 1 Methods: Empirical Correlations Category 2 Methods: Elasticity-Based Approaches Category 3 Methods: Non-linear Load-Transfer Curves Deep Foundation Load Test Databases Overview of Pile Load Test Databases Integrated Pile Load Test Databases Identification of Geomaterial Type Determination of Pile Axial Capacity from SLT Model Uncertainty Assessment and Consideration in Pile Design Background Statistics of Capacity Model Factor Driven Pile Large Diameter Open-Ended Pile (LDOEP)Drilled Shaft Lateral Loaded Drilled Shaft Rock Socket Shaft Shearing Resistance End Bearing Resistance Statistics of Settlement Model Factor Parameterization of Continuous Load-Movement Curves LRFD Calibration Conclusions References Evaluation of Design Methods for Helical Piles Introduction Background Historical and Modern Applications of Helical Piles Installation Equipment General Procedures Industry Survey and Evolution of Design Guidelines Results of Industry Survey Evolution of Design Guidelines State of Understanding of Helical Pile Behaviour Our Current Understanding – “What We Know”Failure Mechanism – Cylindrical Shear or Individual Plate Bearing?Shallow or Deep Failure under Uplift Installation Disturbance Effect on Soil Properties Contribution and Efficiency of Helix to Gross Capacity Areas Needing More Work – “What We Don’t Know”Calculation Methods for Axial Capacity General Cylindrical Shear Method Individual Bearing Method Category 1 Methods I Empirical Capacity-to-Torque Correlation Empirical Correlations with In Situ Test Data Category 2 Methods Helix Capacity Shearing Resistances along Pile Shaft and Soil Cylinder Axially Loaded Helical Pile Load Test Database Compilation of Database – NUS/HelicalPile/1113 CTL|Thompson Data EBS-AFC-HPA Data Reference Data Interpretation of Axial Capacity Model Uncertainty Assessment and Consideration in Helical Pile Design Evaluation of Capacity Model Factor Parameterization of Continuous Load-Movement Curves Application of Model Statistics for Reliability Calibration Conclusions References Generic Foundation Load Test Database Model Factor Statistics for Other Geostructures Resistance of Reinforced Soil Structures Embedment Depth of Cantilever Retaining Walls FS for Slope and Basal Heave Stability Wall and Ground Movement Revision of the JCSS Probabilistic Model Code and Classification Challenges and Concluding Remarks Challenges Technological Innovations in Geotechnical Practice Concluding Remarks References Appendix: Data Availability Statement References

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