Robert D Holtz, School of Civil Engineering, Purdue University, Indiana. This paper was first published in GE’s January 1975 edition.
In Chicago, Illinois, USA, the support of large buildings and other heavy structures on large diameter bored piles is common practice. These foundations are known locally as “caissons”, which is actually a misnomer, but it is too commonly used to be replaced. This particular type of deep foundation has developed, particularly through the innovations of foundation contractors and engineers, into an economical and safe solution to foundation problems in an area with potentially difficult soil conditions.
This article briefly summarises caisson design and construction practice in Chicago and describes some of the recent innovations in inspection and construction procedures. It is hoped that some of the techniques developed over the years in Chicago will be of interest and perhaps can be applied in other parts of the world where similar geologic conditions exist.