Pertemuan 05 Daya Dukung Tanah Matakuliah : S2094 / Rekayasa Pondasi Tahun : 2005 Versi : 1.1 Pertemuan 05 Daya Dukung Tanah

Shallow Foundations Bearing Capacity The problems of soil mechanics can be divided into two principal groups - stability problems and elasticity problems - Karl Terzaghi, 1943

Karl Terzaghi (1883-1963) Father of modern soil mechanics Born in Prague, Czechoslovakia Wrote “Erdbaumechanick” in 1925 Taught at MIT (1925-1929) Taught at Harvard (1938 and after)

Karl Terzaghi at Harvard, 1940

Bearing Capacity Failure; Fargo Grain Elevator, N. Dakota

Transcosna Grain Elevator, Canada Oct. 18, 1913 West side of foundation sank 24-ft

Stability Problem Bearing Capacity Failure Bearing Capacity Analysis How do we estimate the maximum bearing pressure that the soil can withstand before failure occurs?

Bearing Capacity Failures Types/Modes of Failure general shear failure local shear failure punching shear failure

General Shear Failure

Punching Shear Failure

Model Tests by Vesic (1973)

General Guidelines Footings in clays - general shear Footings in Dense sands ( > 67%) -general shear Footings in Loose to Medium dense (30%< < 67%) - Local Shear Footings in Very Loose Sand ( < 30%)- punching shear

Bearing Capacity Formulas

Terzaghi Bearing Capacity Formulas

Terzaghi Bearing Capacity Formulas For Continuous foundations: For Square foundations: For Circular foundations:

Bearing Capacity Factors

Terzaghi Bearing Capacity Formulas D  B No sliding between footing and soil soil: a homogeneous semi-infinite mass general shear failure footing is very rigid compared to soil