Column :
- A member in compression are called column and struct. or
- A reinforced concrete column is a structural members designed to carry compressive loads, composed of concrete with an embedded steel frame to provide reinforcement.
- A column is that which transfer load to the ground and whose height/length not morethan 3 times its lateral least dimension.
- A term strut is used to the compression member in any direction as those on the truss.
- 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.
- 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.
- Minimum 4 bars are used in rectangular column.
- Minimum 6 bars are used in circular column.
- Minimum dia of bars in column is provided 12 mm
- short column is designed on the bases of material strength and applied loads.
- A long column has Slenderness ratio [ the effective length to it least dimension (Le/d >12) ]
- A long column is designed to resist the [ applied load + additional bending moment induced due to its tendancy to buckle ]
- however Slenderness ratio should not exceed more than 60.
- 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.
- For the rcc column have helical reinforcement must have at least 6 bars of longitudinal reinforcement witin the helical reinsforcement
- in a helical rcc column longitudinal bars shall be in contact with the helical reinforcement and equidistance around its inner circumferemces.
- the spacing of longitudnal measured along the periphery of the column shall not exceed 300 mm.
- 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.