Fall 2002


Importance of Settlement During Foundation Design

Md. Anwarul Hoque

 

  The overall safety of the foundation depends on the following two factors

q       It must be safe against shear failure, and

q       It must not exceed tolerable settlement..

It is observed that most of the company give their recommendation on the basis of shear failure, but they donít consider or take cautionary steps regarding settlement failure of the foundation.

Foundation settlement under loads can be classified into three types,

q       Immediate settlement (Si)

q       Consolidation settlement (Sc)

q       Secondary consolidation settlement (Ss)

 In this study the Ss is assumed zero. Because the secondary settlement is not significant for inorganic clays and silly soils. Thus,

Total Settlement= Immediate (Si) + Consolidation (Sc)

An intensive study is carried out on 2 (two) renowned company on their suggested are report. It is observed that the settlement of the individual column footings foundation are greater then the allowable values and thus may cause damage to the structure in future. But as immediate settlement is much less than the allowable value there is less chance of immediate affect. For Raft Foundation, settlement of the raft foundation is within the range of the allowable values, thus casing no future damage.

 As it is observed in our study that settlement has a significant affect on the stability of foundation in the future so during foundation design sufficient safety measure should be taken regarding settlement failure of the foundation.