Basics of Foundation Design

1 F Basics of Foundation Design Electronic Edition, November 2009 Bengt H. Fellenius Dr. Tech., P. Eng. Reference: Fellenius, , 2009. Basics of Foundation Design . Electronic Edition. , 346 p. Basics of Foundation Design Electronic Edition, November 2009 Bengt H. Fellenius Dr. Tech., P. Eng. 9658 First Street Sidney, British Columbia Canada, V8L 3C9 E-address: Web site: November 2009 B A S I C S O F F O UN D A T I O N D E S I G N T A B L E O F C O N T E N T S 1.

2 Effective Stress and Stress Distribution (18 pages) Introduction Phase Parameters Soil Classification by Grain Size Effective Stress Stress Distribution Boussinesq Distribution Newmark Influence Chart Westergaard Distribution Example 2. Cone Penetration Testing (44 pages) Introduction Brief Survey of Soil Profiling Methods Begeman (1965) Sanglerat et al.

3 , (1974) Schmertmann (1978) Douglas and Olsen (1981) Vos (1982) Robertson et al., (1986)and Campanella and Robertson (1988) Robertson (1990) The Eslami-Fellenius CPTu Profiling and Classification Comparison between the Eslami-Fellenius and Robertson (1990) Methods Comparisons Profiling case example Dissipation Time Measurement Inclination Measurement Shear -wave Measurement Additional Use of the CPT Compressibility and Pile Capacity Undrained Shear Strength Overconsolidation Ratio, OCR Earth Stress Coefficient, K0 Friction Angle Density Index, ID Conversion to SPT N-index November 2009 ii Assessing Earthquake Susceptibility Cyclic Stress Ratio, CSR.

4 And Cyclic Resistance Ratio, CRR Factor of Safety, FS, against Liquefaction Comparison to Susceptibility Determined from SPT N-indices Correlation between the SPT N-index, N60, and the CPT cone stress, qt Example of determining the liquefaction risk 3. Settlement of foundations (26 pages) Introduction Movement, Settlement, and Creep Linear Elastic Deformation Non-Linear Elastic Deformation The Janbu Tangent Modulus Approach General Cohesionless Soil, j > 0 Dense Coarse-Grained Soil, j = 1 Sandy or Silty Soil, j = Cohesive Soil, j = 0 Typical values of Modulus Number, m Evaluating oedometer tests by the e-lg p and the strain-stress methods The Janbu Method vs.

5 Conventional Methods Time Dependent Settlement Creep Example Magnitude of Acceptable Settlement Calculation of Settlement Special Approach Block Analysis Determining the Modulus Number from In-Situ Tests In-Situ Plate Tests Determining the E-Modulus from CPT CPT Depth and Stress Adjustment Determination of the Modulus Number, m, from CPT 4. Vertical drains to accelerate settlement (16 pages) Introduction Conventional Approach to Dissipation and Consolidation Practical Aspects Influencing the Design of a Vertical Drain Project Drainage Blanket on the Ground Surface Effect of Winter Conditions Depth of Installation Width of Installation Effect of Pervious Horizontal Zones, Lenses.

6 And Layers Surcharging Stage Construction Loading by Means of Vacuum Pore Pressure Gradient and Artesian Flow Secondary Compression Monitoring and Instrumentation November 2009 iii Sand Drains Wick Drains Definition Permeability of the Filter Jacket Discharge Capacity Microfolding and Crimping Handling on Site Axial Tensile Strength of the Drain Core Lateral Compression Strength of the Drain Core Smear Zone Site Investigation Spacing of Wick Drains Closing remarks 5.

7 Earth Stress (8 pages) Introduction The earth Stress Coefficient Active and Passive Earth Stress Surcharge, Line, and Strip Loads Factor of Safety and Resistance Factors 6. Bearing Capacity of Shallow foundations (16 pages) Introduction The Bearing Capacity Formula The Factor of Safety Inclined and Eccentric Loads Inclination and Shape factors Overturning Sliding Combined Calculation of a Wall and Footing Numerical Example Words of Caution Aspects of Structural Design Limit States and Load and Resistance Factor Design Load factors in OHBDC (1991) and AASHTO (1992) Factors in OHBDC (1991)

8 Factors in AASHTO (1992) A brief history of the Factor of Safety, FS 7. Static Analysis of Pile Load Transfer (58 pages) Introduction Static Analysis Shaft and Toe Resistances Example Critical Depth Piled Raft and Piled Pad foundations Effect of Installation Residual Load Analysis of Capacity for Tapered Piles Factor-of-Safety Standard Penetration Test, SPT November 2009 iv Cone Penetrometer Test, CPTU Schmertmann and Nottingham deRuiter and Beringen (Dutch) LCPC (French)

9 Meyerhof Tumay and Fakhroo The ICP Eslami and Fellenius Comments on the Methods The Lambda Method Field Testing for Determining Axial Pile Capacity Installation Phase Structural Strength Settlement The Location of the Neutral Plane and Magnitude of the Drag Load The Unified Design Method for Capacity, Drag Load, Settlement, and Downdrag Piles in Swelling Soil Group Effect An example of settlement of a large pile group A few related comments Pile Spacing Design of Piles for Horizontal Loading Seismic Design of Lateral Pile Behavior Pile Testing Pile Jetting Bitumen Coating Pile Buckling Plugging of open-two pipe piles and in-between flanges of H-piles Sweeping and bending of piles 8.

10 Analysis of Results from the Static Loading Test (42 pages) Introduction Davisson Offset Limit Hansen Failure Load Chin-Kondner Extrapolation Decourt Extrapolation De Beer Yield Load The Creep Method Load at Maximum Curvature Factor of Safety Choice of Criterion Loading Test Simulation Determining Toe Movement Effect of Residual load Instrumented Tests The Osterberg Test A Case History Example of Final Analysis Results from an O-cell Test Procedure for