BOOK_CONTENT
From Theoretical Foundation Engineering

4.3 TERZAGHI'S BEARING CAPACITY THEORY

Terzaghi (1943) proposed a well-conceived theory for determination of the ultimate bearing capacity of shallow rough rigid continuous (strip) foundations supported by a homogeneous soil layer extending to a great depth. Terzaghi defined a shallow foundation as a foundation for which the width of the foundation, B, is equal to or less than its depth, D f (Fig. 4.1a). The failure surface in soil at ultimate load, q u, per unit area of the foundation, as assumed by Terzaghi is shown in Fig. 4.6. Referring to Fig. 4.6, the failure area in the soil under the foundation can be divided into three major zones. They are:

  1. Zone abc. This is a triangular elastic zone located immediately below the bottom of the foundation. The inclination of of the sides ac and bc of the wedge with the horizontal is ? = ? (soil friction angle).


    Figure 4.5: Settlement at ultimate load for surface foundation on sand (after Vesic, 1963).

  2. Zones acd and bcf. These zones are referred to as Prandtl's radial shear zones.

  3. Zones ade and bfg. These zones are the Rankine passive pressure zones. The slip lines in these zones intersect the ground surface at {45- ?/2) with the horizontal.


Figure 4.6: Failure surface in soil at ultimate load for a continuous rough rigid foundation as assumed by Terzaghi (1943).

The lines cd and cf are...

Copyright Braja M. Das 2007 under license agreement with Books24x7

Products & Services
Air Valves
Air valves allow metered fluid flow in one or both directions. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices.
Pinch Valves
Pinch valves include any valve with a flexible elastomer body that can be pinched closed, cutting off flow, using a mechanism or fluid pressure.
Diaphragm Valves
Diaphragm valves close by means of a flexible diaphragm attached to a compressor.
Water Valves
Water valves are designed to handle and control hot water, cold water, ground water, potable water, salt water and/or wastewater. They are made from metal or plastic.
Borescopes
Borescopes are optical inspection tools that consist of a rigid or flexible tube, an eyepiece on one end, and an objective lens on the other. They use optical relay components to transfer images of bores and cylinders from a tip to an eyepiece.

Topics of Interest

4.4 SOME OBSERVATIONS ON TERZAGHI'S BEARING CAPACITY THEORY It is obvious from Section 4.3 that Terzaghi's bearing capacity theory has been obtained by assuming general shear failure in soil. However...

7.1 Transmitter Types Nuclear plant pressure transmitters are electromechanical systems that are designed to measure pressure and differential pressure (including level and flow). In this book, the...

Flanged End Connections Flanged valves are perhaps the most widely used. Flanges used to mate valves with adjacent piping and/or equipment must conform to the following: They must provide sufficient...

Absorption: The portion of optical attenuation in an optical fiber resulting from the conversion of optical power to heat; caused by impurities such as hydroxyl ions in the fiber. A/B Switch: A...

We mentioned several times in Chap. 9 that the noise analysis technique provides the dynamic response of not only a pressure transmitter but also its sensing line. That is, when the response time of...

Product Announcements
Clippard Instrument Laboratory, Inc.
Protect-Air-by Tri-matic AG
Barksdale Control Products