Column Design

Column : 

1. A member in compression are called column and struct. or 
2. A reinforced concrete column is a structural members designed to carry compressive loads, composed of concrete with an embedded steel frame to provide reinforcement.
3. A column is that which transfer load to the ground and whose height/length not morethan 3 times its lateral least dimension.
4. A term strut is used to the compression member in any direction as those on the truss.
5. column are the important part of the structure a beam and or slab may fail without any serious demage but failure of the column engengers the whole structure so column must be carefully designed.

1. IS 456 Classified rectangular column as a short column when Slenderness ratio  [ the effective length to it least dimension (Le/d <12) ] called short column.
2. Minimum 4 bars are used in rectangular column.
3. Minimum 6 bars are used in circular column.
4. Minimum dia of bars in column is provided 12 mm
5. short column is designed on the bases of material strength and applied loads.
6. A long column has Slenderness ratio  [ the effective length to it least dimension (Le/d >12) ]
7. A long column is designed to resist the [ applied load + additional bending moment induced due to its tendancy to buckle ]
8. however Slenderness ratio should not exceed more than 60.
9. The crossectional are of  longitudnal reinforcement should not less than 0.8% of gross crossectional area of the column and not morethan 6% of gross crossectional area of the column.
10. For the rcc column have helical reinforcement must have at least 6 bars of longitudinal reinforcement witin the helical reinsforcement
11. in a helical rcc column longitudinal bars shall be in contact with the helical reinforcement and equidistance around its inner circumferemces.
12. the spacing of longitudnal measured along the periphery of the column shall not exceed 300 mm.
13. in case of pedestals in which longitudnal is not taken in account in strength calculation, nominal longitudinal reinforcement not  lessthan 0.15% of the crossectional area shall be provided.