Pile Foundations
Introduction:
A deep foundation is a type of foundation distinguished from shallow foundations by the depth they are embedded into the ground. There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints (like property lines). There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete and prestressed concrete.
Development: I- When do we need pile foundations:
· Top layers of soil are highly compressible for it to support structural loads through shallow foundations.
· Lateral forces are relatively prominent.
· In presence of expansive and collapsible soils at the site.
· Offshore structures
· Strong uplift forces on shallow foundations due to shallow water table can be partly transmitted to Piles.
· For structures near flowing water (Bridge abutments, etc.) to avoid the problems due to erosion.
II- Why to use pile foundations:
· Inadequate Bearing Capacity of Shallow
Foundations
· To Prevent Uplift Forces
· To Reduce Excessive Settlement
III- How do they work:
· By Friction between the piles and the soil such as in Fig.1 :
Fig.1
· End bearing piles such as in Fig.2 were the bed rock reaction force is important.
Fig.2 IV- Types of piles:
1. Steel Piles
· Pipe piles, pipe piles are a type of steel driven pile foundation and
A deep foundation is a type of foundation distinguished from shallow foundations by the depth they are embedded into the ground. There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints (like property lines). There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete and prestressed concrete.
Development: I- When do we need pile foundations:
· Top layers of soil are highly compressible for it to support structural loads through shallow foundations.
· Lateral forces are relatively prominent.
· In presence of expansive and collapsible soils at the site.
· Offshore structures
· Strong uplift forces on shallow foundations due to shallow water table can be partly transmitted to Piles.
· For structures near flowing water (Bridge abutments, etc.) to avoid the problems due to erosion.
II- Why to use pile foundations:
· Inadequate Bearing Capacity of Shallow
Foundations
· To Prevent Uplift Forces
· To Reduce Excessive Settlement
III- How do they work:
· By Friction between the piles and the soil such as in Fig.1 :
Fig.1
· End bearing piles such as in Fig.2 were the bed rock reaction force is important.
Fig.2 IV- Types of piles:
1. Steel Piles
· Pipe piles, pipe piles are a type of steel driven pile foundation and