Concrete piles and why when

June 5, 2024 Roberto Magalhães

Compared to other types of pile foundations, concrete piles are often erected as the foundation of many structures.

The article Pile foundations You can find more information about pile foundations here. In this article we will discuss concrete piles.

Why do we need batteries and when do we need batteries?

The following main reasons can be highlighted as prerequisites for the construction of pile foundations.

Weak soil conditions
To support buoyancy forces
To withstand lateral forces
If there is no possibility of absorbing the acting loads through the shallow foundation.

As we know, the most cost-effective type of foundation is the cushion foundation. If soil conditions are poor, it may not be possible to build a shallow foundation, even for a two-story building.

We could try soil stabilization method, or alternatively we could opt for a pile foundation if another method is not viable.

What is a concrete pile?

A pile is a reinforced concrete component that has a round, square or other shaped cross-section or is embedded deeper into the earth.

Types of concrete piles

There are mainly three types of concrete piles, of which prestressed concrete piles are not widely used in construction.

In situ concrete bored piles
Prefabricated piles or driven piles
Prestressed Concrete Piles

Let's discuss each type of concrete pile in detail.

In situ concrete bored piles

The most commonly used type of concrete pile in construction is cast-in-place bored piles. Although the construction process is a little more complicated/difficult compared to other types of concrete piles, these types of pile foundations offer many additional benefits.

The biggest challenge in constructing in-situ concrete bored piles is quality control.

Bored piles are now available in diameters from 600mm to 3,000mm or even larger. The development of the construction industry has expanded the applicability of concrete piles.

Prefabricated piles

Prefabricated piles are also called driven piles. For more information about driven piles, see the article Driven pile Planning and construction of foundations.

Precast piles are comparatively simpler than cast-in-place bored piles. Furthermore, the construction process is not that complicated and the installation of the layers can be done quickly.

Comparison of in situ concrete piles and bored piles

	In situ concrete bored piles	Prefabricated piles
1	The pile is dropped into place	Prefabricated piles are used
two	Mainly anchored in rock	Completed over a layer of hard soil, which is determined based on geotechnical capacity, which is evaluated based on soil parameters
3	Since it rests largely on the rock, a higher final disposition can be achieved	Comparatively, you can expect low-cost bearings
4	Rock surface friction can be taken into account	There was no friction as the post ended above the curved rock.
5	They have greater resistance to buoyancy	Comparatively low buoyancy resistance
6	Casting inclined piles is a challenge	The prefabricated pile can be driven at an angle
7	Completing the pile foundation is a challenge	Completion can be carried out taking into account the settlement of the heads during driving.
8th	Circular shape	Usually square shape
9	As the diameter increases, a greater axial load capacity can be achieved	There are limitations on axial capacity because it is difficult to increase the pile size
10	The quality control and assurance process is very important because the pile is driven underground and visual observation is not possible.	As the pile is driven into place, the construction quality can be monitored.
11	The diameter of the pile may change during construction due to soil collapse (bulging and necking). The integrity of the pile is checked after the construction phase.	The pile may cause structural damage during the driving process.
12	Construction costs would be higher than with other pile foundations	Construction costs would be lower than with in situ concrete piles
13	It takes a long time to complete the construction of piles	Comparatively shorter construction time

Application of different types of concrete piles

In-situ concrete bored piles are used in high-rise construction
Prefabricated piles would be used in buildings with low axial loads.
Driven or precast piles are used in areas where graded piles are present
Construction of bridges and prefabricated piles are being processed

Concrete pile testing

To guarantee the construction quality and load capacity of the piles, the following tests are carried out.

Test type	Test type
Continuous Load Testing (MLT)	To check the load capacity of the pile
Stack Integrity Test (PIT)	Check battery integrity. The test allows you to determine if the post is connected correctly, if there are constrictions, bulges, etc.
Dynamic Pile Testing (PDA)	To check the load capacity of the pile
Cross Hole Sonic Integrity Test for Wood Poles	Check the integrity of the pile with the reinforcing cage.
Bidirectional Pile Loading Tests	To check the load capacity