The piles are point-type construction elements used for deep foundations in construction sites, which allow the transmission of loads from the structure to deeper soil layers have sufficient load capacity to support them.
The piles transmit loads to ground receiving structure through a combination of lateral friction or shaft resistance and penetration resistance or resistance per tip.
They can be made of ordinary reinforced concrete with prestressed concrete -like light poles, with metal or wood sections.
The piles are driven vertically on the ground surface by means of punches, used for that one ram, or metal blade equipped machines to blow masses or with a jackhammer.
This allows the pile down, penetrating the ground, until the depth of layers of resilient flooring is reached and the “rejection” of the ground in case of a pile to work for “tip” or occurs reach the depth design, in case of a pile which work by “friction”.
Once driven into the ground, this has on the pile and across its surface side, an adhesive strength increases to continue digging more piles in the vicinity, can be achieved by this procedure, a ground consolidation .
Types of foundation piles
In this pilot system, the soil is displaced from the space that will occupy the pile to compact the same, due to the action of penetration efforts. Densification can be generated, possibly beneficial in loose granular soils.
Sometimes the driving of these piles can cause upheavals of the ground, thrusts on neighboring elements and other actions almost always harmful structures near the site and installation services.
Within this pile types are the most important:
- Precast piles, kneeling by the impact hammer – driven piles and cast impact on the site
- Piles screwed
- Piles penetrated by continuous pressure, as produced by cats.
Drilled piles or in situ:
In this system the floor space that will take the pile by digging or drilling techniques, thus forming a cavity inside which steel armor is placed and subsequently filled with concrete is removed.
The bored piles are more favorable in soils possess sufficient cohesiveness to remain open during drilling, inspection and concreting. With this approach drawbacks such as noise and vibration generated by the equipment used in avoiding piles displacement.
Uses of Piles in Foundation
Piles are used in many ways. Using them is often necessary to ensure the structural safety of a building or engineering work.
When the charges borne by the building can not be distributed properly in a shallow foundation exceeding the carrying capacity of the soil.
When the soil immediately produce unforeseen foundation seats and the resistant layer is at some depth; For buildings is that support in poor quality ground.
In cases where the land is subject to considerable variations in temperature and shrinkage produced swellings expansive clays.
If the building to be constructed will be located on water or ground water near the ground level.
In high-rise buildings exposed to high winds.
In buildings that require working elements strength, as cable structures, or anchored in the ground structure.
When you need to resist inclined loads; as in the retaining walls of the docks.
When should recalzar foundations exist.
The bridge piers and abutments are usually built on foundation piles to prevent the possible loss of load capacity than a superficial foundation suffer from soil erosion on the soil surface.
The foundations of some structures such as transmission towers and slabs of basements below the water table, are subjected to uplift forces. Sometimes piles are used for those foundations and so resist the lifting force.