Pile Foundations
CHAPTER ONE INTRODUCTION
1. OVERVIEW OF FOUNDATIONS The word foundation is derived from a latin word fondare meaning to set or ground on something solid. A foundation is that part of a structure which transmits the weight of the structure to the ground in a manner that the soil below does not fail in shear and the settlement is within the safe limits. Foundations are broadly classified into two categories: • Shallow Foundation • Deep Foundation A shallow foundation, according to Terzaghi is one whose width is greater than its depth ie. D/ B < or = 1.
The main types of shallow foundations are footings are footings and raft or mat foundation. Footings can be further subdivided as shown below: • Strip Footing • Spread or Isolated footing • Combined Footing • Strap or Cantilever Footing. The loads must be "spread" to the soil in a manner such that its limiting strength is not exceeded and resulting deformations are tolerable. Shallow foundations accomplish this by spreading the loads laterally, hence the term spread footing. Whereas spread footing (or simply footing) supports a single column, a mat is a special footing used to support several randomly spaced columns or to support several rows of parallel columns and may underlie a portion of or the entire building. The mat may also be supported, in turn, by piles or drilled piers. Foundations supporting machinery and such are sometimes termed bases. Machinery and the like can produce substantial load intensity over a small area, so the base is used as a load-spreading device similar to the footing. Deep foundations are analogous to spread footings but distribute the load vertically rather than horizontally. The terms drilled pier and drilled caisson are for the pile type member that is constructed by drilling a 0.76m diameter hole in the soil, adding reinforcing as necessary, and backfilling. On the other hand, a
1. OVERVIEW OF FOUNDATIONS The word foundation is derived from a latin word fondare meaning to set or ground on something solid. A foundation is that part of a structure which transmits the weight of the structure to the ground in a manner that the soil below does not fail in shear and the settlement is within the safe limits. Foundations are broadly classified into two categories: • Shallow Foundation • Deep Foundation A shallow foundation, according to Terzaghi is one whose width is greater than its depth ie. D/ B < or = 1.
The main types of shallow foundations are footings are footings and raft or mat foundation. Footings can be further subdivided as shown below: • Strip Footing • Spread or Isolated footing • Combined Footing • Strap or Cantilever Footing. The loads must be "spread" to the soil in a manner such that its limiting strength is not exceeded and resulting deformations are tolerable. Shallow foundations accomplish this by spreading the loads laterally, hence the term spread footing. Whereas spread footing (or simply footing) supports a single column, a mat is a special footing used to support several randomly spaced columns or to support several rows of parallel columns and may underlie a portion of or the entire building. The mat may also be supported, in turn, by piles or drilled piers. Foundations supporting machinery and such are sometimes termed bases. Machinery and the like can produce substantial load intensity over a small area, so the base is used as a load-spreading device similar to the footing. Deep foundations are analogous to spread footings but distribute the load vertically rather than horizontally. The terms drilled pier and drilled caisson are for the pile type member that is constructed by drilling a 0.76m diameter hole in the soil, adding reinforcing as necessary, and backfilling. On the other hand, a