PILES::
Pile groups which are required to resist the combined effects of vertical and horizontal forces imposed
on earth retaining structures such as bridge abutments for example, achieve the necessary resistance by
the provision of raking piles installed at a slope in the opposite direction to the horizontal forces and/or
the resistance to horizontal movement provided by the soil surrounding the piles and against the pile
cap (subgrade reaction).
In circumstances when a pile is installed through compressible soil strata which undergo consolidation
after the pile is in place, the downward movement of the consolidating soil and of any overlying soils
relative to the pile will cause a downward drag on the shaft of the pile. This is termed 'negative skin
friction'. These conditions sometimes arise in the case of bridge abutments, when the retained
embankment causes down drag mainly on the rear piles of the supporting group.
"Before the design engineer can consider what type of pile is best suited to a project the following
basic information is needed as a minimum requirement.
• Detailed geotechnical information
• Structural details and loadings
• Allowable total and differential settlements
• Knowledge of the site and its environs
Using this information, the engineer will need to consider the following points regarding the various
piling systems so that the most suitable foundation system can be chosen for the project.
The function of piled foundations is to transmit the applicable combinations of permanent and
transient loads which are applied at the top of the piles, through weak compressible soil or fill
materials onto stiff or dense soil strata or rock at lower levels, in such a manner as to prevent excessive
settlement, horizontal displacement or rotation of the supported structure.
Piles are slender, 'column like' structural members, usually acting in groups, which are installed
vertically or at a slope (rake) in the ground by various techniques, to sufficient depth to achieve the
necessary load bearing capacity through frictional resistance along their sides, end bearing resistance
at their bases, or combinations of both.
on earth retaining structures such as bridge abutments for example, achieve the necessary resistance by
the provision of raking piles installed at a slope in the opposite direction to the horizontal forces and/or
the resistance to horizontal movement provided by the soil surrounding the piles and against the pile
cap (subgrade reaction).
In circumstances when a pile is installed through compressible soil strata which undergo consolidation
after the pile is in place, the downward movement of the consolidating soil and of any overlying soils
relative to the pile will cause a downward drag on the shaft of the pile. This is termed 'negative skin
friction'. These conditions sometimes arise in the case of bridge abutments, when the retained
embankment causes down drag mainly on the rear piles of the supporting group.
"Before the design engineer can consider what type of pile is best suited to a project the following
basic information is needed as a minimum requirement.
• Detailed geotechnical information
• Structural details and loadings
• Allowable total and differential settlements
• Knowledge of the site and its environs
Using this information, the engineer will need to consider the following points regarding the various
piling systems so that the most suitable foundation system can be chosen for the project.
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