Daya dukung tanah (bearing capacity)

Kuliah-1 (CES 31017)T.Ilyas

Bahan referensiBraja M Das, Principal of Geotechnical Engineering, fourth edition, PWS Publishing Company, 1998, BostonMuni Budu, Soil Mechanics and Foundations, 2nd

edition, John Wiley & Sons, 2007, USABouwles, Foundation Analysis and design, 5th edition, Mc Graw-Hill, 1997 R.F. Craig, Soil Mechanics, (English & terjemahanProf.Dr.Ir Budi S Supandji)Cernica, J.N., Soil Mechanics, John Wiley & Sons,1995Holtz, R.D., Kovacs, W.D., An introduction to Geotechnical Engineering, Prentice Hall, N.J., 1981

Penilaian (grader)

UTS 30%UAS 30%Tugas/responsi 10%Praktikum 30%

Tugas diberikan melalui SCeLE (Student Center e-Learning Environment) ditambah tugas responsi.

Bearing capacity

The lower part of a structure is generally referred to foundation.Its function is to transfer the load throught out the soil without overstressing the soil

Allowable bearing capacity (qa )

Defined as the maximum pressure that may be applied to the soil that 2 fundamental requirement are satisfied

1. the factor of safety with respect to shear failure of the supporting soil must be adequate2. the settlement of the foundation should be tolerable

Ultimate bearing capacity (qu )

Defined as the least pressure that will cause complete shear value of the soil in the vicinity of the foundation

Failure mechanism

General shear

Local shear

Punching shear

General and local shear failure

Terzhagi’s (1943) bearing capacity (general shear)

Terzaghi’s bearing capacity capacity factors (general shear)

Effect of ground water table

q = γ

Df

Factor of safety (Fs

)

Definition of allowable bearing capacity:Gross allowable bearing capacity

Net allowable bearing capacity

whrere q= γ

Df

hence

Gross allowable bearing capacity with factor of safety respect to shear value

Good practice used

Bearing Capacity examplesA continous footing is shown below. Using Terzaghi’s bearing capacity factors, determine qall per unit area that footing can support. Take safety factor of 3.

q = γ

D

Bearing cap factorNc , Nq , N γ

from Terzagi’s

table