Dynamic analysis of multistep piles on Pasternak soil subjected to axial tip forces

The dynamic analysis of a foundation pile on a two-parameter elastic soil i s performed, in the presence of non-classical boundary conditions. The soil discontinuities are simulated through the introduction of n step variation s of the cross-section, whereas the partial restraints at the top and at th e bottom are taken into account by imposing non-classical boundary conditio ns. Finally, the pile is supposed to be subjected to a conservative axial l oad at the tip. The analysis can be considered to be exact, in the framewor k of the Euler-Bernoulli hypothesis, the differential equation of motion is deduced and solved, and the frequency equation is derived for an arbitrary number of steps. Some numerical examples complete the paper. (C) 1999 Acad emic Press.