What is Footing?
- The footing is generally supporting columns and may be round, square, or rectangular at a plan and in section.
- They may be of the slab — stepped or sloping type. Thia stepped footing results at a better distribution of load than a slab footing.
- A sloped footing isn’t less economical, although constructional problems are associated with this sloping surface.
- The isolated spread footing at plain concrete has the advantage that the column had is transferred to the soil through dispersion at the footing.
- In reinforced concrete footings. i.e., pads. This slab is treated as an inverted cantilever bearing this soil pressure and supported by the column.
- Where a two-way footing is provided, it can be reinforced at two directions of bending with bars of steel placed in this bottom of the pad parallel to its sides.
- If clearances permit, two-way square footings used to reduce the bending moments. Where not less than one column is placed on pads (combined footing).
- Their shapes can be rectangular or trapezoidal; the latter produces a more economical design where large differences of the magnitude of the column loads exist or where rectangular footings cannot be accommodated.
- This gives pad-type/ combined footings and their behavior under external loads and bearing pressures: typical reinforcement detailing for two different combined footings in sectional elevations and plan.
- The specifications and quantities can change depending on the column loads and the spread area.
Type of footing
- Isolated Footing:
- Combined Footing:
- Continuous Wall Footing:
- Strap Footing:
- Strip Footing:
- Raft Footing:
- Pile Footing:
What is Foundation?
- Foundation Engineering is a subject built on the basic principles of Soil Mechanics, Soil Hydraulics, and Structural Mechanics.
- All these three together may be considered as the pillars of Foundation Engineering.
- A wrong application of the principles of any one of the three subjects may lead to a faulty design of the foundation.
- Theories have been developed for the design of foundations to suit ideal soil conditions.
- However, such conditions rarely exist in nature since soils found in natural conditions are mostly heterogeneous in character.
- Theories can have to be modified or adjusted to suit field conditions.
- A foundation is a part of a superstructure.
- The stresses and strains that are brought to the foundation from the superstructure would lead to interaction between the foundation structural element and the soil surrounding it.
- It is this interaction that is very difficult to evaluate, as this is quite a complex phenomenon.
- The theories that have been developed for ideal conditions do not take into account all the variables that would lead to the interaction between the soil and the foundation element.
- The presence of a water table would make the interaction problem all the more difficult to solve.
- It is, therefore, essential that a design engineer should have a thorough knowledge of the theories he wants to use for the design of foundations and also its limitations.
- Knowledge of the theories and its limitations by themselves will not lead to the design of a safe and sound foundation if the environmental conditions, the strength and settlement characteristics of the soil are not properly known in advance.
- An ideal design engineer, therefore, is the one who has a thorough knowledge of the theories and the field conditions and also who can modify or adjust the design to suit the field conditions.
- This requires, therefore, a practical and pragmatic approach to the problem of design and construction while keeping in view the safety and economics of the project.
Type of Foundation
- Shallow foundation
- Individual footing or isolated footing
- Combined footing
- Strip foundation
- Raft or mat foundation
- Deep Foundation
- Pile foundation
- End Bearing Pile
- Friction Pile
- Drilled Shafts or caissons
- Pile foundation
- Shallow foundation
Difference Between Footing and Foundation
|1||A formation which is in contact with the ground.||A structure which transfers its gravity loads to earth from superstructure.|
|2||A structure which transfers the load from the superstructure to this ground||the foundation which is in contact with the earth.|
|3||This is a provides support to the entire building||This provides support to individual columns.
|4||It analogized with the feet of the leg.||It can be analogized with the feet of the leg.|
|5||Foundation are of two types, shallow & deep foundation||This footing is a type of shallow foundation
|6||This is the basement of the wall||This is under the foundation wall.|
|7||This Footing includes slab, rebar which are fabricated of brickwork, masonry or concrete.||Foundation types include piles, caissons, footings, piers, the lateral supports, and anchors.|
|8||Footing reinforces support to an individual column.||this is Foundation is extensive support because it gives support to a group of footings as an entire building|
|9||the number of footings repose on a foundation.||This Foundation is the support that bears all kinds of loadings.|
|10||This is Footing transmits loads directly to the soil.||This is foundation is in direct contact with the soil and transmits it to the ground.|
|11||All foundations can't be footing||But all footings are foundations.
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