114 CHAPTER FOUR
degree. For piles less than 50 ft (15.2 m) long, Kis more likely to be in the
range of 1.0 to 2.0, but can be greater than 3.0 for tapered piles.
Empirical procedures have also been used to evaluate from in situtests,
such as cone penetration, standard penetration, and relative density tests. Equa-
tion (4.17), based on standard penetration tests, as proposed by Meyerhof, is
generally conservative and has the advantage of simplicity:
(4.24)
where average standard penetration resistance within the embedded length
of pile and is given in tons/ftfs^2 .*
N
fsN
50
fs*Meyerhof, G. G., “Bearing Capacity and Settlement of Pile Foundations,” ASCE Journal of
Geotechnical Engineering Division, 102(GT3):1976.