1. Pertemuan 06 Daya Dukung Tanah
Matakuliah : S2094 / Rekayasa Pondasi
Tahun : 2005
Versi : 1.1
Pertemuan 06 Daya Dukung Tanah

2. Further Developments Skempton (1951) Meyerhof (1953)
Brinch Hansen (1961)
De Beer and Ladanyi (1961)
Meyerhof (1963)
Brinch Hansen (1970)
Vesic (1973, 1975)
See Extra Handout

3. Vesic (1973, 1975) Formulas Shape factors….… Eq. 6.14, 6.15 and 6.16
Depth Factors ……. Eq. 6.17, 6.18 and 6.19
Load Inclination Factors …. Eq. 6.20, 6.21 and 6.22
Base Inclinations factors .. Eq and 6.26
Ground Inclination Factors…. Eq and 6.28
Bearing Capacity Factors …. Eq. 6.29, 6.30 and 6.31

4. Bearing Capacity of Shallow Foundations
6.3 Groundwater Effects
6.4 Allowable Bearing Capacity
6.5 Selection of Soil Strength Parameters
6.6 Local & Punching Shear Cases
6.7 Bearing Capacity on Layered Soils
6.8 Accuracy of Bearing Capacity Analyses
6.9 Bearing Capacity Spreadsheet

5. Allowable Bearing Capacity
F …. Factor of safety

6. Factor of Safety Depends on: Type of soil
Level of Uncertainty in Soil Strength
Importance of structure and consequences of failure
Likelihood of design load occurrence

7. Minimum Factor of Safety

8. Selection of Soil Strength Parameters
Use Saturated Strength Parameters
Use Undrained Strength in clays (Su)
Use Drained Strength in sands,
Intermediate soils that where partially drained conditions exist, engineers have varying opinions; Undrained Strength can be used but it will be conservative!

9. Accuracy of Bearing Capacity Analysis
In Clays …..Within 10% of true value (Bishop and Bjerrum, 1960)
Smaller footings in Sands…. Bearing capacity calculated were too conservative – but conservatism did not affect construction cost much
Large footings in Sands … Bearing capacity estimates were reasonable but design was controlled by settlement

10. Accuracy; Bearing Capacity Analysis