Deep foundations have different types and various forms to carry out their construction process, in this article we are going to tell you their meaning, what they are, what they are for, in which situations you should use them and their variety so that you take it into account at the time. to perform one of these.
What are deep foundations?
A deep foundation is defined as the one in charge of transporting the load of a structure through soils that are characterized by being weak or filled to types of soils or rocks that have a greater bearing capacity and that are less understandable in depth, or by some functional reason.
Why are deep foundations made?
The deep foundations are made well below the surface of the ground so that the structure to be built does not suffer any type of damage such as differential settlements or any other surface condition that may generate a problem. This type of foundation is generally found at depths greater than 3 meters below the finished soil level.
In other words, deep foundations are used when you need to transfer the load from a structure to a deeper stratum that has adequate bearing capacity or is competent enough to support the loads of the structure you are planning to build. In other words, the terrain that is near the surface is inadequate to support the load of said structure and for this reason an excavation of greater depth, rather than superficial, must be carried out in order to find a layer with an optimal capacity. bearing.
Other cases where you can use deep foundations
In construction work it is possible to find different obstacles to carry out a project, the realization of deep foundations is not an exception, for this reason we are going to tell you which are these different cases that exist so that you take them into account at the time to make a deep foundation.
When a shallow foundation does not support the stresses of a structure
Deep foundations are chosen when the stresses transmitted by a structure cannot be optimally distributed using semi- deep foundations, shallow foundations , or when choosing another solution that is likely, but this solution does not meet the guidelines or exceeds the bearing capacity of the type of soil it can reach. This means that deep foundations are capable of reaching the type of soil with optimal bearing capacities at great depths, which cannot be achieved by other types of foundations that achieve shorter lengths.
By seasonal variations of the terrain
Deep foundations are a good option when the land where you plan to carry out your project may show seasonal variations, either due to retraction or swelling.
When unpredictable seats arise
If the layers that are close to the foundations can generate any type of unpredictable settlement at a certain depth, this can happen in soils that are characterized by being filled or of low quality.
What should you do to avoid unpredictable seats and seasonal variations?
It is very important that you know how to choose between the different types of foundations for each type of soil, for this reason a tip for this is to carry out an adequate soil study or also known as a geotechnical study , in the final report of this you will have many recommendations to know the types of soils that your project has and the detail of the foundations recommended for its optimal execution.
When building on water
Another case in which it is a good choice to use a deep foundation is when executing a project that will be built on water, this is due to the instability that the terrain that is closest to the surface can present.
When tensile foundations are required
That is, as it happens with large buildings that are subjected to forces by the wind, or in those structures that require elements subjected to traction to obtain stability, as is the case of cable structures or others that are anchored to the floor.
To resist inclined loads
An example of this case are the piles that are installed in the docks in order to resist the impact that the hulls of the ships give them at the time of docking, this type of deep foundation is also known as sheet piling.
When making structural reinforcements
There are many existing structures that present structural problems and one of the best options to control this problem is through structural reinforcement, also known as underpinning of existing foundations.
Types of deep foundations
The deep foundations are elements of the construction of great help when supporting loads. To this is added that they have a great classification or variety, among these are the screen walls, the substitution foundations, the floating foundations and the piles. Next, we will describe the most common and widely used types of deep foundations for different types of projects.
Sheeting walls or milan wall
The screen walls or also known as Milan walls are part of the classification of deep foundations, they are frequently used in buildings that have considerable heights, they act as a retaining wall and are characterized by having different advantages such as saving the costs and further development of surfaces. The screen walls are the foundations most used in urban areas for buildings that have basements, for parking spaces and with the aim of being retaining walls for the underground water that is presented in roads and tunnels.
The substitution foundation is carried out by means of the excavation of the land, where the weight of the material to be extracted and excavated will have the same proportion with respect to the construction to be carried out; It is important that each of the soil layers, the characteristics of the structure that it will support, and the loads that will act on the foundation, are known.
Floating foundations are based on the principle that Archimedes postulated, according to him the bodies that are immersed in some static liquid will experience an upward vertical push identical to the weight of the volume of the liquid that is dislodged from it . For this reason, it is important that it is foreseen in these constructions that the raincoats are perfectly executed by calculating the reaction to the vertical upward thrust, this in order to prevent the structure from sinking or overturning.
Deep foundation with piles
The deep foundation system with piles or piloting is characterized by being one of the different types of point-type foundations, this system is installed on the ground using different techniques that are capable of finding, at great depths, the soil stratum characterized by being able to withstand the loads that a structure transmits to it. The system of deep foundations with piles is one of the most used, when it comes to supporting large loads, worldwide.
Deep foundation with Micropiles
The micropiles are elements of great use in the construction of foundations, these are responsible to reinforce and support various structures through the steel shell that is inside. The casing or also known as basket is introduced after having drilled the ground to the depth and with the necessary diameter, then it is filled with high-strength concrete, at CortEquipos we are experts in the realization of micropiles and we have machines that fit projects with little space.
At present , wooden piles are very little used due to their cost and the type of structures they must support, among their different types are those treated, untreated and treated in depth, this type of foundation is characterized by using them at the moment to withstand soils with alkaline or highly acidic presence.
The steel piles are characterized by steel parts that melt or in other cases are prefabricated with the objectives to be driven and fulfill the task of supporting a structure, the prefabricated piles have two classifications are the solid piles and small displacement.
The driven piles and displacement piles are a type of foundation that is used very often when laying the foundation of bridges and walls, for supporting tanks, buildings and others. The pile driving system can be carried out using two well known systems which are pressure driving or percussion driving.
Precast concrete piles
The piles precast concrete are designed in molds where its steel casing is inserted and filled with concrete, are capable of withstanding very heavy loads of different kinds of structures, the category of the piles of reinforced concrete is divided into two, these are cast-in-place piles and precast piles.
You already know what a deep foundation is, the cases where you can use it, the advantages it can offer you and its different types for you to use in your projects. Cortequipos is a company specialized in the construction process of deep foundations and other types of foundations, for this reason we can help you whenever you need to analyze or carry out the type of deep foundations that your project needs.