The question asks about the required extension length of bottom bars in footing slabs beyond the column boundary.
Footing Slab Reinforcement Extension
According to standard structural design practices for reinforced concrete footings:
- Bottom bars under columns provide structural integrity and must extend sufficiently into the footing slab.
- This extension prevents stress concentration and ensures proper load transfer.
- The required extension distance is specified relative to the column dimensions.
Required Bar Extension Distance
For effective load distribution and anchorage:
- The bottom bars under columns should extend into the footing slab.
- The minimum required extension is 42 diameters.
- This distance is measured from the outer edge of the column.
Therefore, the bottom bars under the columns are extended into the interior of the footing slab to a distance greater than 42 diameters from the outer edge of the column.
Important Questions from Footings
For a number of columns constructed in a row, the type of foundation provided is
If p is the net upward pressure on a square footing of side b for a square column of side a, the maximum bending moment is given by
A. \({\rm{B}}.{\rm{M}} = \frac{{{\rm{pb}}\left( {{\rm{c}} - {\rm{a}}} \right)}}{4}\)
B. \({\rm{B}}.{\rm{M}} = \frac{{{\rm{pb}}{{\left( {{\rm{b}} - {\rm{a}}} \right)}^2}}}{4}\)
C. \({\rm{B}}.{\rm{M}} = \frac{{{\rm{pb}}{{\left( {{\rm{b}} - {\rm{a}}} \right)}^2}}}{8}\)
D. \({\rm{B}}.{\rm{M}} = \frac{{{\rm{pb}}\left( {{\rm{b}} + {\rm{a}}} \right)}}{8}\)
_______ is provided to support an individual column. It is circular, square or rectangular slab of uniform thickness Sometimes it is stepped or haunched to spread the load over a large area.
The minimum nominal cover to reinforcement for R.C.C. footings as per IS: 456-2000 shall be
For a proposed building, raft foundation, isolated footings and combined footings are being considered. These foundations are to be listed in the decreasing order of preference in terms of performance. Which one of the following is the correct order of listing?
