Isolated Footing Design

Design Of Isolated Footing:

There are different types of foundation based on no. of a factor. The isolated footing is one of the most popular and simplest types of foundation used worldwide. Foundation are very important to the building. Ultimately the entire load of the building is transferred to ground through the foundation.
Isolated footing are most commonly used footing for Reinforced cement concrete column because it is simple and most economical. An isolated footing is used to support a single column.Isolated footing are independent footing which are provided for each column.

This type of footing is used when

1. Columns are not closely spaced
2. Loads on footing are less.
3. The safe bearing capacity of the soil is generally high.

The objective of the Design of Isolated Footing is to Determine:

1. Area of footing.
2. Thickness of footing
3. Reinforcement Details of footing with a satisfying moment and shear force consideration.
4. Check for development length and shearing stresses.

The Design Steps Followed In The Design Of Footing Are :

1. Find out an area of footing based on factored loads.
2. Assume suitable thickness of the footing.
3. Find out the critical section for flexure and shear.
4. Find out bending moment and shear forces at the critical section.
5. Check the adequacy of the assumed thickness.
6. Find out reinforcement detail.
7. Check for bearing stresses.
8. Check for development length.

Isolated Footing Design Example:

1. Column = 14" x 14"
2. Steel grade = fy= 60 Ksi
3. fc' = 3 Ksi (for footing)
4. fc' = 4 Ksi (for column)
5. sL.L = 260 kips
6. sD.L = 390 kips
7. bearing capacity = qa =6 ksf 5' below the grade.