Piles and Pile Foundations

by Carlo Viggiani, Alessandro Mandolini and Gianpiero Russo

Piles and Pile Foundations: Piles have been used by humankind for foundation purposes since prehistoric times, but in the last few decades the development in equipment and installation techniques, and the pressure towards constructing in areas with poor subsoil properties, have led to spectacular progress in the piling industry.

According to Van Impe (2003) bored and CFA piles account for 50% of the world pile market, while the remainder is mainly covered by driven (42%) and displacement screw piles (6%). Different proportions may be found locally; for instance displacement screw piles represent about 60% of the total installed yearly in Belgium while bored and CFA piles reach more than 90% in Italy.

Piles and Pile Foundations: Since the behaviour of piles depends markedly on the effects of the installation technique, their design is a complex matter which, although based on the concepts of soil mechanics, inevitably relies heavily on empiricism.

The aim of Piles and Pile Foundations is twofold. First, it reports an overview of the present design practice for pile foundations, trying to summarize some of the findings of recent research and to evaluate the above practice in the light of this research.
Second, it is shown that the deeper insight of piled foundations behaviour achieved in the last decades may be used for a more rational and economic design of piled rafts.