What are the functions of foundation?
Following are the main functions of foundations :
- To transmit and distribute the total load of the structure to a larger area of underlying support.
- To prevent differential settlement of the structure.
- To provide stability to the structure.
What are machine foundations?
Machine foundations are special types of foundations required for machines, machine tools and heavy equipments which have wide range of speeds, loads and operating conditions. These foundations are designed considering the shocks and vibrations (dynamic forces) resulting from operation of machines.
What are the requirements of an ideal machine foundation?
There should be no resonance. The center of gravity of machine and foundation should coincide. The vibration produced by machines should not cause any disturbance to persons and nearby structures. The ground water table should be at least at a depth of one fourth the width of foundation below foundation level.
What are the basic requirement of foundation?
Foundation structure should be designed in such as way that possess enough safety against exceptional future loads for example earthquake and overloading. It should resist attack from chemicals in soil. Various harmful materials like sulfates may be present in groundwater and soil that deteriorate concrete foundation.
What are the three requirements for a safe structure?
The 3 “S” are Safety, Space and Structure, meaning that the planned process should provide a safe working environment to construction workers, sufficient space to perform construction activities and the required sequence of construction operations and project phases.
What are the types of footing?
The different types of footings used in construction are described below:
- Continuous Wall Footing. The footing which supports a long masonry or RCC wall is known as a continuous footing.
- Isolated Footing.
- Combined Footing.
- Strip Footing.
- Strap Footing.
- Raft Footing.
- Pile Footing.
Which type of footing is best?
Isolated footings are provided where the soil bearing capacity is generally high and it comprises of a thick slab which may be flat or stepped or sloped. This type of footings are most economical when compared with the other kind of footings. Economical when columns are placed at longer distances.
What are the 3 types of foundations?
But chances are your house has (or will have) one of these three foundations: full basement, crawlspace, or slab-on-grade. Other variations are possible. Here are the three main types of house foundations that you will encounter in residential construction.
What is standard footing size?
As you can see, heavy houses on weak soil need footings 2 feet wide or more. But the lightest buildings on the strongest soil require footings as narrow as 7 or 8 inches. Under an 8-inch-thick wall, that’s the same as saying you have no footing.
How do I know my footing size?
How to Calculate Footing Size
- Determine the width and length of the cement slab in inches.
- Divide the width by 12 to convert it to feet.
- Divide the length by 12 to convert it to feet.
- Determine the depth or thickness that is required for the footing in inches.
- Multiply the width by the length and then by the depth.
How do you calculate footing depth?
General factors to be considered for determining depth of foundation are:
- Load applied from structure to the foundation.
- Bearing capacity of soil.
- Depth of water level below the ground surface.
- Types of soil and depth of layers in case of layered soil.
- Depth of adjacent foundation.
How deep and wide should a footing be?
Depth, Width, and Thickness of Footings Footings should extend to a minimum depth of 12 inches below previously undisturbed soil. Footings also must extend at least 12 inches below the frost line (the depth to which the ground freezes in winter) or must be frost-protected.
What is the minimum depth of footing?
minimum depth of foundation:– minimum depth of foundation is around 5 feet for a small residential building from ground level or at least 1.50 times the width of footing. In cold climates the depth of footing is Kept at a minimum of 1.50m below surface because of possible frost action.
What type of footing is most common in residential construction?
Individual footing or an isolated footing is the most common type of foundation used for building construction. This foundation is constructed for a single column and also called a pad foundation.
How do you calculate steel footing?
Example – Footing Bar Bending Schedule
- Length of Footing = X = 2m.
- Breadth of Footing = Y = 1.6m.
- Height of the footing (Thickness) = h =0.3m.
- Diameter of the Main reinforcement bars = dm= 12mm.
- Diameter of Distribution Reinforcement Bars = dd =12mm.
- Spacing of Main reinforcement bars = sm = 150mm c/c.
What is thumb rule in construction?
Thumb rules enable you to calculate the solution using a simple mathematical formula and make smart decisions whenever needed. Thumb rule is an approximate & comparing method. In thumb rules, The units are not the same when we compare to get the results. So never consider units while performing thumb rule.
What is the ratio of steel in concrete?
For example a multi-storied building meant to be strong rather than a 3 storied building….Ratio of Steel required to Cement Concrete.
| Different Parts of the Building | Requirement of Steel TMT Bars in Kg |
|---|---|
| Bases | 90-130 |
| Floor Slabs | 80-120 |
| One way Slabs | 75-125 |
| Two way Slabs | 67-135 |
How do you calculate footing weight?
Step 1: Size of the footing Given P = 1400 kN and qc = 150 kN/m2. Assuming the weight of the footing and the back file as 10 per cent of the load, the required base area is: 1400(1.1)/150 = 10.27 m2. Provide 3400 x 3400 mm giving 11.56 m2 (Fig. 11.29.
How do you create an eccentric column footing?
How to Design Eccentric Footing? The eccentric footing is designed in such a way that the C.G (center of gravity) of the superimposed load coincides with the C.G of the base area so, resulting in uniform bearing pressure this footing is subjected to concentric loading.
How do you calculate footing design?
Design Calculation of an Isolated Footing
- INTRODUCTION. Footings are the bases laid on the soil on top of which a structure is erected.
- PROPORTIONING OF FOOTING FOR COLUMN:
- Column B:
- Check for Bending Moment:
- Check for One-way shear.
- Check for two-way shear.
- Check for Bearing Stress.
- Check for Development Length.
What is a cantilever footing?
A cantilever footing is a component of a building’s foundation. It is a type of combined footing, consisting of two or more column footings connected by a concrete beam.
What is eccentric loading in footing?
Footings that are not concentrically loaded are known as “Eccentric Footings”. In addition, when footings are subjected to an axial load “P” and bending moment “M” or lateral force “H”, the footing will experience unbalanced stress distributions along the base of the footing.
Where is eccentric footing used?
This is used in cases where restrictions exist on the usable ground area outside of the build-up foundation area such as perimeter boundaries ( building is exactly at the boundary ), connecting buildings etc.
What is eccentricity load?
Distance between the actual line of action of compressive or tensile loads and the line of action that would produce a uniform stress over the cross section of the specimen.
What is eccentricity in civil engineering?
The degree to which two forms fail to share a common center; for example, in a pipe or tube whose inside is off-center toth regard to the outside. The degree of eccentricity can be expressed by a plus or minus wall thickness tolerance. …
What is isolated 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.
What are the advantages of combined footing?
A combined footing is used in the following conditions: When two columns are very close enough to each other such that their footing overlap. When the load-bearing capacity of the soil is low, the requirement of more area under the individual footing.
What is difference between footing and foundation?
The foundation is general expression for structural element that support the superstructure as well as the supported soil, while the footing is represent the shallow structural element that support the superstructure.
What is a stepped footing used for?
Stepped Footings allow depth of footings to transition from one elevation to another.