Citation

Anderson WC. Highw. Res. Board bull. 1960; 247: 1-13.

Copyright

(Copyright © 1960, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

To have an upright cantilever structurally strong enough and at the same time as economical as possible, requires careful analysis of the supporting foundation. However, neither time nor money permit foundations to be put in that way. It is usually much cheaper to make a foundation enough larger to include expected factors of ignorance and safety. Nevertheless, some engineering must be used and the solution contained in this paper is a good beginning point. Certain observations about horizontal soil resistances seemed to be established enough to use as a basis to start. The first is that for a vertical cantilever, a slim deep foundation is the most economical for a given load with limits of the strength of the foundation as an efficient structure. The soil has horizontal resistance to movement depending on its cohesive or granular makeup, or both. The resistance varies with the depth or the amount of overlying earth above. There is some relation between movement and resistance. In this analysis it is assumed that (1) within the limits used the soil is an elastic body, (2) the strength of a foundation varies with its projected area, (3) no part of the soil shall be stressed above its ability to withstand the load, and (4) in empirical solution errors shall be kept on the side of over-design. In the solution itself, several empirical methods were used. It was impractical to design a foundation in a given soil for a given load at a given height, but if one took a foundation of given dimensions in a given soil and chose a neutral axis, then by integrating the soil resistance one finds both shear and moments imposed. A family of curves can then be drawn, from which generalizations and empirical solutions follow. This type of analysis seems to be justified from model studies and tests run in 1945, then on some 12 years of usage covering many thousands of poles from 20 to 200ft high supporting any type of load, and latest on the tests run by the research department of the ohio state highway department.