File Name: types of foundation and their uses .zip
Foundation is one of the essential parts of the structure. It is defined as that part of the structure that transfers the load from the structure constructed on it as well as its weight over a large area of soil in such a way that the amount does not exceed the ultimate bearing capacity of the soil and the settlement of the whole structure remains within a tolerable limit.
Foundation is the part of a structure on which the building stands. The solid ground on which it rests is known as foundation bed. As we know that there are different types of soil, and the bearing capacity of the soil is different for each type of soil. Depending on the soil profile, size, and load of the structure, engineers chose different kinds of foundation.
In general, all foundations are divided into two categories, - shallow and deep foundations. The terms Shallow and Deep Foundation refer to the depth of the soil at which it is placed. The main aspects of different types of foundation, along with their images, are given below.
As economic feasibility is one of the main factors in the type selection, it is also discussed briefly with each type. To know other factors that affect the range of foundation read: Factors Considered for Selection of Foundation. As the shallow foundation depth is low and it is economical, it is the most popular type of foundation for lightweight structures.
Several types of shallow foundations are discussed below. This is the most widely recognized and most straightforward shallow foundation type, as this is the most economical type. They are typically utilized for shallow establishments to convey and spread concentrated burdens caused, for instance, by pillars or columns. They are generally used for ordinary buildings Typically up to five stories.
Isolated footing comprises a foundation directly at the base of the segment. Generally, every section has its footing. They straightforwardly transfer the loads from the column to the soil.
It might be rectangular, square, or roundabout. It can comprise both reinforced or non-reinforced material. For the non-reinforced footing, however, the stature of the footing has to be more prominent to give the vital spreading of the load. They should possibly be utilized when it is sure beyond a shadow of a doubt that no differing settlements will happen under the whole structure. Spread footings are inadmissible for the orientation of large loads.
It is given to lessen the twisting minutes and shearing powers in their primary areas. The size of the footing can be roughly calculated by dividing the total load at the column base by the allowable bearing capacity of the soil. To decide when to use shallow foundations, it is necessary to know when it is economical.
It is economical when:. Wall footing is also known as continuous footing. This type is used to distribute loads of structural or non- structural load-bearing walls to the ground in such a way that the load-bearing limit of the soil isn't outperformed. It runs along the direction of the wall. The width of the wall foundation is usually times the width of the wall.
The wall footing is a continuous slab strip along the length of the wall. Stone, brick, reinforced concrete, etc. The combined footing is very similar to the isolated footing.
When the columns of the structure are carefully placed, or the bearing capacity of the soil is low and their footing overlap each other, combined footing is provided. It is fundamentally a blend of different footings, which uses the properties of various balances in a single footing dependent on the necessity of the structure. The foundations which are made common to more than one column are called combined footings.
There are different types of combined footing, including slab type, slab and beam type, rectangular, raft, and strap beam type. They may be square, tee-shaped, or trapezoidal. The main objective is the uniform distribution of loads under the entire area of footing, for this is necessary to coincide with the center of gravity of the footing area with the center of gravity of the total loads.
Strap footings are similar to combined footings. Reasons for considering or choosing strap footing are identical to the combined one. In strap footing , the foundation under the columns is built individually and connected by a strap beam. Generally, when the edge of the footing cannot be extended beyond the property line, the exterior footing is connected by a strap beam with interior footing. It is also recommended in situations where the bearing capacity of the soil is inadequate, the load of the structure is to be distributed over a large area or structure is subjected continuously to shocks or jerks.
In this type, the whole basement floor slab acts as the foundation. The total load of the structure is spread evenly over the entire area of the structure. This is called raft because, in this case, the building seems like a vessel that floats on a sea of soil. Raft foundations are economic when:. You can also read:. Pile is a common type of deep foundation.
They are used to reduce cost, and when as per soil condition considerations, it is desirable to transmit loads to soil strata which are beyond the reach of shallow foundations. Pile is a slender member with a small cross-sectional area compared to its length. It is used to transmit foundation loads to a deeper soil or rock strata when the bearing capacity of soil near the surface is relatively low.
Pile transmits load either by skin friction or bearing. Piles are also used to resist structures against uplift and provide structures stability against lateral and overturning forces. Pile spreads load either by skin friction or bearing.
It can again be classified based on its material and its mechanism of load transfer or function. Several types of pile foundations are shown in the following chart. Pier is an underground structure that transmits a more massive load, which cannot be carried by shallow foundations.
It is usually shallower than piles. The pier foundation is generally utilized in multi-story structures. Since the base region is determined by the plan strategy for the regular establishment, the single pier load test is wiped out.
Along these lines, it is increasingly well known under tight conditions. Pier foundation is a cylindrical structural member that transfer heavy load from superstructure to the soil by end bearing. Unlike piles, it can only transfer load by bearing and by not skin friction. Caisson foundation is a watertight retaining structure used as a bridge pier, construction of the dam, etc. It is generally used in structures that require foundation beneath a river or similar water bodies.
The reason for choosing the caisson is that it can be floated to the desired location and then sunk into place. Caisson foundation is a ready-made hollow cylinder depressed into the soil up to the desired level and then filled with concrete, which ultimately converts to a foundation. It is mostly used as bridge piers. Caissons are sensitive to construction procedures and lack construction expertise.
To conclude, the foundation is a structural supporting member that transfers the total load form slab, beam, column, wall, etc. The main objective of the foundation is to provide stability to the total structure and safely transfer the total load from the structure to the soil at an optimum cost. Please note that the information in Civiltoday. The information provided should not be used as a substitute for professional services. Cement Hydraulic Cement. Bridge Building Equipment Wall. Deep Foundation What is Pile Foundation?
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When a depth of foundation is less than the width of foundation then it is known as Shallow Foundation. Generally, shallow foundation placed no more than 6 ft depth from the lowest finished floor. The shallow foundation has a minimum depth of about mm and the maximum depth, not more than 4 meters the ground. Footings are the important structural element which transfers the load of column, beam, slab and retaining structures to the soil safely. It is one of the simplest and worldwide popular types of foundation. An isolated footing is mostly used to support a single column.
Individual Footing or Isolated Footing.
Surely everyone knows it is the essential part of the structure which transfers its overall load upon an area of soil. However, the load should not exceed the ultimate bearing capacity of the soil. The primary purpose of the foundation to make the structure stable and resist the structure from vertical and lateral forces. If the width of the foundation is smaller than the depth of the foundation is called the Deep Foundation. A part of the foundation helps to transmit the load of the structure to soil with proper distribution of the loads and it is made of concrete and reinforced cement concrete.
Content of this article : Types of foundations, Spread footing foundation, Benching or stepped foundation, Pile foundation, classification of piles foundation, Piles can be classified according to material-wooden piles,concrete piles,RCC piles, sheet piles,classification is based on the mode of working of the piles, i Bearing pills, and ii Friction piles. The following are the different types of foundations, which are generally used for different structures :. This type of foundation can normally be used for three to four-storied buildings on common type of alluvial soils. The depth and width of foundation depends on the bearing capacity of the soil and the intensity of load. For example, for the foundation of 1 J brick thick wall, three offsets excluding concrete offset, will be provided. This type of foundation is provided on hilly places or in those situations where the ground is sloppy. In this foundations the excavation trenches are made in the form of steps.
Foundation depth usually involves depth, measured from the terrain surface, to the base surface through which the foundation transfers the structure load to the soil.Reply