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VERTICAL VIBRATION OF FLOATING PILES

BY

MILOS NOVAK

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Research

THE FACULTY OF ENGINEERING SCIENCE

THE UNIVERSITY OF WESTERN ONTARIO

LONDON; ONTARIO

CANADA

N6A 589

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Vertical Vibration of Floating Piles

by f

Milos Novak1,M.ASCE

Introduction

Vertical vibration of piles has to be considered when de

signing footings or structures for dynamic vertical loads or

for horizontal loads which produce rotation of the pile cap.

Such loads are most often generated by wind, earthquake and

the operation of machines.

When the pile vibrates, its stiffness is modified and

damping is generated through interaction of the pile with the

surrounding soil. These phenomena are very complex and little

understood. As a result of this piles are sometimes quite

ignored and their reactions are replaced by those of an elas­

tic half-space. Conversely, in other approaches to piles the

soil is more or less ignored.

Vertical response of piles has received even less atten­

tion than horizontal response, which has been studied by

Penzien (7) and a few others. Two theories were published

recently concerning vertical excitation (3,4). Both of them

assumed a fixed tip (end bearing piles). Experiments have

shown, however, that the vertical response can be much more

affected by the motion of the tip than the horizontal response

lprofessor,Faculty of Engineering Science, The University of Western Ontario, London, Ontario, Canada N6A 5B9.