ABSTRACT
ART. 9.1. INTRODUCTION W h e n it is necessary to construct foundations where soil of poor bearing capacity extends to such a depth that the cost and diffi culty of sinking piers to a hard stratum would be considerable, pile foundations frequently provide the most reliable and economical solution. For any set of soil conditions, a wide choice is available to the engineer in regard to the type, size, length and number of concrete piles suitable to carry a given concentration of loading. Concrete piles fall into three main types: precast piles, cast-in-situ driven piles, and cast-in-situ bored piles. Each of these types have certain advantages and disadvantages under different circum stances, and the merits of the various types are discussed in Articles 9.4 and 9.5.
