Pile Foundations: Structural Features, Installation Procedure

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-05-24 22:24

The advantages and disadvantages of this choice
Sorting of pile-strip foundations of the building
Barrel wall thickness
Blade thickness
Coating
Pile foundations video

The foundation of the main building is its support on which everything rests. So to speak, it represents the skeleton of the future building. With the foundation laid, you do not have to worry about soil or ground shifts and deformation of the room, which could cause significant damage to the appearance.

Any specialist will agree that in order to choose the right foundation, you need to carefully consider the possible options and choose the one that is most suitable. There are many types of this foundation. The choice falls on the one that is suitable for all indicators that are considered at the very beginning of construction. For example, parameters such as soil composition or detected groundwater are important here. Details on the types and types of pile foundations

For a long time, the most used was the strip foundation, which was easily laid by yourself or with the help of specialists. The monolithic foundation lay deep into the ground. Over time, many cases have proven that this type of foundation is extremely unsafe for many buildings.

Thus, in the modern world I extensively use pile-tape or deep tape types of foundations, which become "legs" on which the entire structure rests.

The advantages and disadvantages of this choice

It should be noted that this type of foundation is an excellent solution for weak, swampy and uneven terrain. It fits perfectly even on mountain slopes, which is one of the main advantages in choosing just such a base. It is extremely easy to build the desired building with it yourself if you follow the instructions of the selected instructions.

Advantages of the pile-strip type of foundation:

It doesn't take a lot of materials to lay and strengthen the base of the building. This will save material resources.
There is no need to be afraid of soil shifts, the foundation will withstand. He is not afraid of any hesitation.
Withstands a lot of weight, which is ideal for multi-storey buildings.
Can be installed without specialist assistance. Perfect for a master who is confident in his abilities and desires.
The concrete mix is also prepared independently, which is very convenient. You don't have to resort to expensive purchases.

Disadvantages of the pile-strip type of foundation:

It is important to carry out all the calculations necessary to start construction. Here, more often than not, it is impossible to do without the help of a master from the outside. However, without this it is better not to lay such a foundation.
The walls of the planned structure should not be too heavy, otherwise destruction of the base and an abundance of cracks are possible.
If you plan to finish the basement, there will be difficulties with the arrangement inside such a foundation.

Sorting of pile-strip foundations of the building

This type of foundation is divided into several grades, or so-called classes. The difference between them lies in the fact that the shape of the "legs" (supporting installations) is different for everyone.

It is extremely important to choose the right one, since not only the appearance, but also the safety of the future structure depends on it. Recently, the following classes of this foundation are popular:

Pile-screw. It looks like a single scaled screw. Most often, it is screwed into the ground using special machinery and equipment. However, you can install such a base yourself. It is only important to prepare by studying all the necessary information about what may be required in the process.
Pile-bored. In this case, bored beams (piles) are used, but the base itself remains of the tape or pile-tape type. Then a well is drilled, which is a prerequisite for laying such a foundation. Drilling continues until hard soil becomes an obstacle. The well is then reinforced, after which the concrete is poured. All these actions can be reproduced independently.

Pile deepening in the ground

If we talk about averaged soils with sufficient bearing capacity, then screw piles for low loads include:

single-bladed with a blade diameter up to 500 mm inclusive, blade thickness up to 6 mm inclusive and a barrel wall thickness up to 4.5 mm inclusive;
multi-bladed with a blade diameter up to 300 millimeters inclusive, blade thickness up to 5 millimeters inclusive and a barrel wall thickness up to 3.5 millimeters inclusive.

They are used in the construction of IZhS facilities and industrial structures comparable in terms of loads. Subject to the use of piles with similar parameters under more severe loads and in especially dense soils, it is necessary to use rolled metal of greater thickness to increase the structural rigidity.

Screw piles for heavy loads include structures:

with one blade with a diameter of more than 500 millimeters, a blade thickness of more than 6 millimeters and a barrel wall thickness of more than 4.5 millimeters;
with two or more blades with a diameter of more than 300 millimeters and a thickness of more than 5 millimeters, the thickness of the barrel wall of which is more than 3.5 millimeters.

They are used in the construction of large civil and industrial facilities.

There is also a point of view that piles should be assigned to the first or second load group based on the diameter of the trunk. This is permissible, but only when it comes to wide-blade piles of large lengths and diameters (over 6 meters and over 159 mm) or narrow-blade piles. In the case of narrow-blade structures used in especially dense seasonally freezing and permafrost (permafrost) soils, the thickness of the metal is of no less importance, which acts as an additional basis for classification.

Barrel wall thickness

According to the thickness of the barrel wall, screw piles are divided into piles of small thickness (up to 3.5 mm inclusive), medium thickness (over 3.5 mm) and thick-walled (6 and more millimeters).

The first group (up to 3.5 mm inclusive) is recommended for the construction of light buildings and structures (gazebos, fences, etc.), which are classified as responsibility class III (reduced), provided that they are used in non-aggressive soil conditions.

The second group (over 3.5 mm) is used for buildings that transmit an average load to the foundation (responsibility class III (reduced), as well as for buildings of II (normal) responsibility class, but only in areas represented by non-aggressive soils.

When building in medium and highly aggressive soils and / or under heavy loads (responsibility classes II (normal) and I (high), it is better to use thick-walled screw piles.

The thickness of the metal is selected at the stage of project development, taking into account the data on the corrosiveness of the soil at the construction site, which is described in detail in the article "Selection of the thickness of the barrel wall based on the requirements for the service life". To clarify the correctness of the selection of parameters, it is recommended, after performing the calculation of durability, to check the residual thickness of the barrel wall for compliance with the design loads and the requirements of GOST 27751-2014

Blade thickness

If we talk about the thickness of the blade, now in construction, piles with a blade thickness of up to 5 millimeters inclusive and 6 or more millimeters are used.

As in the case with the thickness of the barrel wall, structures belonging to the first group can be used only in the construction of light buildings and structures, temporary objects. For long-term buildings, large civil and industrial facilities and for aggressive soil conditions, piles with a blade thickness of 6 mm or more are recommended. The blade thickness is selected at the stage of project development, taking into account the data on the corrosiveness of the soil.

Coating

The coating is referred to as additional measures to protect screw piles from corrosion, since during installation in the ground, structures experience a significant abrasive effect. It is more effective to increase the thickness of the metal and use high quality steel.

Screw pile manufacturers mainly use the following coatings:

polymer;
rust enamel primers;
polyurethane;
epoxy;
zinc (obtained by hot or cold galvanizing).

But it cannot be denied that the application of the coating, provided that its integrity is preserved, allows to reduce the negative impact on the above-ground part of the pile and on the area in the "atmosphere-soil" contact area.