Common types of concrete piles

Prestressed concrete piles

It is a type of pile that is manufactured on the line, maintained on the line and carried out entirely in the factory. Prestressed concrete piles includes two types of shapes: round piles and square piles. Prestressed centrifugal concrete piles are produced by centrifugal rotation with the compressive strength grade of concrete from B40 to B60. The length and thickness of the pile wall depends on the outer diameter of the pile.

Piles are used in cases where the geological background does not have obstacles such as farmland or newly leveled land. The construction of piles can use many methods such as hammer lowering piles, pressing machine, twisting methods or water erosion methods. Prestressed centrifugal piles can be inserted much deeper than normal reinforced concrete piles, so they take advantage of the load capacity of the ground, so the number of piles in a grating is small, the layout and construction are also easy, saving the cost of building a foundation mat. Due to the use of high-strength concrete and steel, the reduction in reinforcement cross section leads to a reduction in weight, which is convenient for transportation and construction.

Another advantage of prestressed centrifugal concrete piles is the  large horizontal load capacity because the concrete in the pile is pre-prestressed, so it increases the tensile capacity of concrete, thereby increasing waterproofing and corrosion resistance.

Bored Pile

It is a type of concrete pile that is poured in place in holes created by drilling or equipment pipes. The pile diameter is usually 0.6m, 0.8m, 1.0m, 1.2m, 1.4m. The pile length is not limited depending on the geological conditions of the building. Bored Piles have a much larger cross section and nose depth than prefabricated piles, so although the unit resistance is smaller, the load capacity is still greater, so the number of piles in a pile grating is less, the arrangement of the pile in underground works is also easier, so when the construction load is very large, we should use bored piles.

Regular reinforced concrete piles

A pile manufactured at a workshop or construction site made of precast reinforced concrete and pressed into the ground by equipment. The common pile edge in Vietnam is 0.2 – 0.4m, the pile length is usually less than 12m because the maximum length of a steel rod is 11.7m. Concrete used for piles from 250 – 350 (equivalent to durability grade
(B20 – B25).

Reinforced concrete piles are often used appropriately and well in new residential environments, in newly leveled geological plan, and with obstacles. In this case, reinforced concrete piles are capable of penetrating complex geological layers and obstacles while ensuring that the pile does not crack, the technician can completely control the quality of the pressed pile.

The advantages of centrifugal concrete piles

Centrifugal concrete piles are manufactured and managed in the factory environment so uniform quality is maintained. Using concrete with a high grade of 60-80N/mm3 along with centrifugal rotation, and the impact of pre-stress improves the bearing structure of the pile and other superior features of the pile:

• High tensile resistance.
  • Large bending moment
  • Anti-cracking pile
  • Sulfate and reinforcement anti-corrosion.
  • There is no stress that causes twisting and cracking during the pressing process.
  • Allows pressing through hard stratigraphic layers.
  • Construction can be carried out in narrow areas in urban areas with neighboring structures,
  making no noise.
  • Make the most of the pile length, do not have to cut off the pile head when constructing the pile grating.
  • The friction force of the pile wall increases due to the presence of mortar inserted around the pile wall
•  At the same length of the pile, the drop pile has the greatest load capacity.
  • Overcoming potential damages of other options such as deflection of pile head, broken pile head, wrong pile lowering of design height

Centrifugal concrete pile application

Centrifugal concrete piles are used as foundations for works such as power stations, high-rise buildings, bridges, overpasses, harbors, marine structures, retaining walls,…