What Is Deep Foundation | Types of Deep Foundation

What Is Deep Foundation?

A deep foundation, as per its deep foundation definition, is one that transfers a load of a building by using solid soil layers or rock beds which are accessible at vast depths.

Deep foundations are necessary whenever the soil during or close to the ground is incapable of sustaining a building and loads must be transferred to deeper layers.

A deep foundation is a base which is installed at a considerable length under the surface of the ground and transmits building loads to the earth at depth. Any such foundation’s depth to width ratio is frequently more than 4 to 5.

The building of a deep foundation is more complex and costly than that of a shallow foundation.

Also, Read: What Is Lintel Beam | Lintel Beam Size | Types of Lintel Beam

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Types of Deep Foundation

Following are the 4 types of deep foundation

Pile Foundation
Pier Foundation
Cession or Well Foundation
Buoyancy Rafts

1. Pile Foundation

The type of deep foundation in which load is transferred to a lower level using vertical members known as piles.
A pile is a thin structural part that can be composed of steel, concrete, or wood.

A pile driven into the piles might be made of wood, concrete, or steel.

This form of foundation is commonly used when hard strata are available at significant depth and the bedding is uneven, or the topsoil has a low bearing capacity, or there are substantial swings in subsoil water level, or the topsoil is expansive. The load on a pile foundation is transferred through friction as well as bearing.

Pile foundations are foundations in which load is carried to a lower level using vertical elements known as piles. A pile is a thin structural part that can be composed of steel, concrete, or wood.

A pile can be rammed into the ground or built in place by excavating a hole and filling it with concrete. These piles can be made of wood, concrete, or steel.

When to Use a Pile Foundation Is Preferred?

The load from the user structure is heavy and unevenly distributed. When a structure is placed on a seashore or river bed, the foundation is vulnerable to the scouring action of water. As a result, they are beneficial in marine structures.

The pile foundation will be used for projects in areas where canals, deep drainage lines, and other structures will be built near the foundation.

The bearing capacity of the topsoil is low.

The raft foundation or grillage foundation is likely to be prohibitively expensive or difficult to build. The subsoil water level is high, making pumping water from open trenches for the shallow foundation problematic and inefficient.

Also, Read: H-Beam vs I-Beam | What Is H-Beam | What is I-Beam

Types of Pile Foundation

1.1 Depending on the Material

Concrete piles are constructed with concrete. There are both precast and cast-in-place piles. Precast concrete piles are made in a workshop and afterwards pushed through into earth at the desired location.

Prepare timber piles using seasoned wood. Those were typically circular in shape, with diameters ranging from 20cm to 50cm.

Steel piles can be made of a single or hollow pipe piece. Since of their tiny cross-section, all of those are particularly nice to maneuver.

Composite piles are made of a combination of wood and concrete. Underwater, wooden heaps are much more resilient.

1.2 Depending on the Function

Bearing piles are pushed all the way to the hard stratum. They transfer the structure’s load to the hard stratum beneath. These piles serve as simulated columns. On their ends, these piles utilized to support vertical loads.

Friction piles are employed when the soil is extremely loose or soft to a significant depth. From the surrounding dirt, friction builds along the pile’s surface.

The friction balances the structure’s load

Sheet piles are often small and thin mounds. Manufacturers produce plates made of concrete, wood, and steel.

Such piles typically run into the ground to separate members or to prevent water seepage; these really aren’t designed to transport vertical loads.

Also, Reda: What Is Inverted Beam | Advantages of Inverted Beam | Purpose of Inverted Beam

2. Pier Foundation

A pier is a vertical column with a cross-section that is bigger than that of a pile. In a dry environment, a pier is constructed by excavating a big diameter cylindrical hole to the necessary depth and then backfilling it with concrete.

The distinction between a pier and a cast-in-situ pile is relatively arbitrary. A pier is a cast-in-place piling with a diameter bigger than 0.6 m.

The manner of construction is the difference between a pile foundation and a pier foundation. Pier foundations just carry the load through the bearing, whereas pile foundations transfer the load through friction and bearing.

Pier foundations are typically shallower in-depth than pile foundations. When the top layers consist of decomposed rock overlying strata of sound rocks, a pier foundation is preferred.

It becomes difficult to drive bearing piles into the decomposed rock in this situation.

A pier foundation can be easily built-in stiff clays that offer significant resistance to the driving of a bearing pile.

Types of Pier Foundation

2.1 Concrete Pier or Masonry Pier

The concrete pier is built of concrete. There are both precast and cast-in-place piers. Precast concrete piers are built in a factory and then pushed into the ground at the desired location.

Steel wires are commonly used to reinforce precast concrete piers.

It has a cross-section of 30 cm to 50 cm and a length of up to 20 metres. At the bottom of the pier, there is a cast steel shoe.

2.2 Drilled Caisson

Engineers use the phrases drilled caisson, foundation pier, and sub pier interchangeably to refer to a cylindrical foundation.

A huge compressed member drilled into a caisson that is subjected to an axial force at the top and reaction at the bottom.

Drilled Sessions Are Usually Drilled Mechanically.

There Are Three Varieties of Drilled Cession:

The bottom of a concrete caisson has been widened.
The cession of a steel pipe that has been filled with concrete.
In a steel pipe, there is a cession with a concrete and steel core.

Brick masonry and concrete foundation pier in dug pits could be used where a good bearing stratum occurs up approximately 5m beneath ground level.

The pier’s size and spacing are determined by the depths of the solid bed, the composition of the overlying soil, as well as the superimposed load.

Also, Read: What Is Slab Beam / Hidden Beam / Concealed Beam | Advantage and Disadvantage

3. Cassion Foundation

A Cassion is a foundation in the shape of a hollow prismatic box that is constructed above ground level and then buried to the desired depth in one piece.

It’s a water-light chamber that’s used to create foundations underwater, such as rivers, lakes, and harbors.

This is a portion of the foundation for the Well.

It is a watertight chamber that is used to create foundations underwater, such as in rivers, harbors, and lakes.

The Cassion Can Be Classified into Three Categories

The top and bottom of the open Cassion are both open, and the caissons are hollow chambers. The caisson’s bottom has a cutting edge.

When the soil encompassed in an open Cassion cannot be excavated satisfactorily, a pneumatic caisson is required. During the sinking operation, its shaft.

Large hollow boxes that are open at the top and closed at the bottom make up a floating Cassion . These float to the location where the caissons will be erected in the end.

These were filled with sand, ballast, dry concrete, and gravel and sunk at that location.

Also, Read: Difference Between Beam and Column | What Is Beam | What Is Column

4. Buoyancy Rafts

Buoyancy rafts, often referred as hollow box foundations, are meant to generate a semi-buoyant or buoyant substructure beneath whereby the soil is loaded at a moderate frequency.

These could be built in open excavations or sunk into the ground like caissons.

Traditional foundations are much more costly as buoyancy rafts. As a result, their application is mainly limited to areas with deep silts, soft sands, and other alluvial deposits, and where loads could be maintained concentric.

Plans that call for subterranean tanks or that make it cost-effective to incorporate deep basements into to the design are widespread.

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Advantages of Deep Foundation

Here, let’s explain deep foundation pros as follows

Because piles can be constructed off-site, they can be installed quickly on-site.
The earth is displaced and compacted by the induced piles, increasing the pile’s bearing capacity.
For many years, the facility will be safe and robust thanks to the piles.
Boost your overall productivity.
Driving through stones and boulders quickly damages a pile.
Saltwater marine bits can cause damage to piles.
A stack cannot be higher than the ground.
It’s tough to predict the exact duration needed ahead of time.
When the piles are driven, vibrations are produced, which have an impact on the surrounding area structures.

Disadvantages of Deep Foundation

Here, to define deep foundation more clearly, the cons are as follows.

Corrosion can occur in piles.
Inspection is required on a daily basis.
To repair the piles, skilled labor is required.

FAQ

Deep Foundation

A deep foundation is a type of foundation which is placed at a greater depth below the ground surface and transfers structure loads to the earth at depth. The depth to width ratio of such a foundation is usually greater than 4 to 5.

Foundation Helical Piles

Helical piles are installed by rotating the shaft of the pile. As the shaft rotates, the helical plate advances into the ground “pulling” the shaft with it. This action is much like a wood screw. A helical pile is generally used to resist compression and lateral loading.

Deep Foundation Companies

Basements.
Buoyancy Rafts (Hollow Box Foundations)
Caissons.
Cylinders.
Shaft Foundations.
Pile Foundations.

Deep Rock Foundations

Deep Rock Foundations has 5.0 stars.

Deep Foundation Contractor

Deep foundations include piles, piers and caissons or compensated foundations using deep basements and also deep pad or strip foundations. Deep foundations can be used to transfer the loading to a deeper, more competent strata at depth if unsuitable soils are present near the surface.

Helical Piles for House Foundation Cost

The cost of a helical pier depends on the design, size, and weight of the structure and the adjacent soil conditions. Due to these many variables, an installed helical pier can range in price from $15-$30 per foot. So, a typical 20-foot helical pier can cost between $300 – $600 each.

Drilled Caisson Foundation

Drilled shafts, also referred to as drilled piers, caissons or bored piles, are deep foundation solutions used to support structures with large axial and lateral loads by excavating cylindrical shafts into the ground and filling them with concrete.

Piles Foundation

A pile foundation is defined as a series of columns constructed or inserted into the ground to transmit loads to a lower level of subsoil. A pile is a long cylinder made up of a strong material, such as concrete. The piles support the structure by remaining solidly placed in the soil.

Helical Pile Foundation

When getting pricing from us you will notice that helicals can cost around $30 dollars per foot. Meaning a helical around 20-ft can be estimated around $600 dollars.

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What Is Deep Foundation | Types of Deep Foundation