In sites of poor ground, piles can be used to transfer the loads from the building into deeper stratum. They transfer these loads via friction, end bearing or a combination of both.
If the piles were to fail, there can be very serious consequences; the most notable local example being an apartment block in Wilton which had to be demolished about ten years ago.
Piles can fail for a number of different reasons; communication is vital between all parties during the construction process, particularly on sites with variable ground conditions.
Failure modes include buckling where the slenderness ratio is high in very poor soils or punching failure where an end bearing pile ‘punches’ through a strong formation into an underlying weak formation.
This property in Cork City, constructed over twenty years ago, is suffering from foundation movement due to the failure of the pile(s) supporting the corner. A trial hole revealed a 800mm*800mm*800mm pile cap supporting a 400*400 ground beam.
The site was located on an obsolete Waulsortian limestone quarry which was made up over the years; hence the piles. Considering that Waulsortian limestone is a geohazard, it may have had something to do with the pile failure.