What is the difference between spread footing and mat foundation?

What is the difference between spread footing and mat foundation?

A spread footing is a circular, square or rectangular slab of uniform thickness. A mat or raft foundation is a large slab supporting a number of columns and walls under the entire structure or a large part of the structure.

When would you use a mat footing?

Mat footings are used when the building load is so high, that spread or strip footings could not bear the weight or their employment would be inefficient. Furthermore, mat footings are helping to reduce the varying settlements caused by construction on non-homogenous soils or uneven load distribution on the footing.

Is spread footing the same as pad footing?

Isolated footings (also known as Pad or Spread footings) are commonly used for shallow foundations in order to carry and spread concentrated loads, caused for example by columns or pillars. Isolated footings can consist either of reinforced or non-reinforced material.

Under what conditions mat foundation is used?

Mat foundations are popular in areas where basements are common. Mat foundation is also used for low bearing capacity soil in order to spread the load of a building and hence construct a stable foundation. It is used to reduce differential settlement of buildings.

How thick should a mat foundation be?

Depending on the total load applied to the mat and underlying foundation system, the thickness of mat foundations can vary from 1 ft (0.3 m) to more than 20 ft (7 m). The reinforcing system in the mat can be quite substantial, with heavy reinforcing bar mats in the bottom, top, or both locations within the mat depth.

What are the different type of combined footing?

Types of Combined Footing The combined footing may be rectangular, trapezoidal or Tee-shaped in plan. The geometric proportions and shape are so fixed that the centeroid of the footing area coincides with the resultant of the column loads. This results in uniform pressure below the entire area of footing.

What is the advantage of mat foundation?

Mat foundation can be provided where the shallow foundation is necessary but soil condition is poor. It resists differential settlement. Mat foundation requires less earth excavation. Mat foundation itself can be considered as a floor slab.

Is mat foundation the same as slab on grade?

What is the difference between a slab on grade and a mat foundation? Slabs on grade are very lightly loaded. Mat foundations are intended to support heavy column loads and are intended to “throw the loads” lower into the soil profile but at lower stress levels because of the large area.

What is meant by Spread Footing?

Spread footing is a type of the shallow foundation. It is defined as the structural members used to support the column and walls as well as transmit and distribute the load coming on the structure to the soil beneath it. Spread footing increases the life of the buildings by controlling the damage in the structures.

What is combined footing foundation?

Combined footings are constructed for two or more columns when they are close to each other and their foundations overlap. The function of a footing or a foundation is to transmit the load form the structure to the underlying soil.

Which foundation is better for reclaimed ground?

If the load of the structure which are to be constructed on such lands is not too heavy, the raft foundation will be the best choice. But, if the load of the structure is too heavy and unevenly distributed, pile foundation should be considered.

What is the minimum thickness of mat foundation?

As per IS 1080, a minimum depth of 50 cm shall be used for mat foundation. This is required to ensure that the soil has a safe bearing capacity which is assumed in the design. The depth of mat foundation must satisfy shear requirements.

What is spread footing?

A spread footing is a type of structural component that acts as a base for a building’s foundation.

What is a mat slab foundation?

A mat foundation is a type of foundation system that unifies the floor slab and footing support areas in a continuous concrete pour.

What are different types of footings?

A deep foundation is used to transfer the load of a structure down through the upper weak layer of topsoil to the stronger layer of subsoil below. There are different types of deep footings including impact driven piles, drilled shafts, caissons, helical piles, geo-piers and earth stabilized columns.

What is a mat footing?

A mat foundation is used when the subsoil is weak and column loads are so heavy that the conventional spread footings cover more than 50 % of the building area. It is common to use mat foundation or deep basements to transfer the column loads to the underlying soil as well as provide floor slab for the basement.