Reinfocing details of column
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This document provides details about reinforcing concrete columns and footings. It discusses that columns are vertical members that support loads and transmit them downward. Reinforcement is added to reduce column size and resist compression and bending forces. The main reinforcement runs longitudinally and is arranged in square, rectangular, or circular patterns. Minimum and maximum longitudinal steel requirements are specified. Transverse reinforcement is also included to help position longitudinal bars and confine the concrete.
Reinfocing details of column
- 1. REINFORCING DETAILS OF RCC COLUMN &FOOTING
- 2. Column • Columns are vertical compression members of a structural frame intended to support the load-carrying beams. They transmit loads from the upper floors to the lower levels and then to the soil through the foundations. • Usually columns carry bending moment as well, about one or both axes of the cross section, and the bending action may produce tensile forces over a part of the cross section • Reinforcement are provided in order to reduce the size of the column
- 3. • The main reinforcement in columns is longitudinal, parallel to the direction of the load and consists of bars arranged in a square, rectangular, or circular shape
- 4. • Main steel is provided to resist compression load along with concrete • Reinforcement Requirements (Longitudinal Steel Ast) min Ast 0.8 % of C/S max Ast 6% of C/S
- 5. • The object of stipulating a min. percentage of steel is to make provision to prevent buckling of column due to any accidental eccentricity of the load on it • For stipulating a max. percentage of steel is to provide reinforcement with in such a limit to avoid congestion of reinforcement which would make it very difficult to place the concrete and consolidate it
- 6. • Min. 4 bars in rectangular/square column and min. 6 bars in circular shape column • The bar shall not be less than 12mm • The nominal cover shall any case not be less than 40mm. • In our site they provided 40mm cover • Min. distance b/w individual bars -the dia of larger bar -5mm more nominal max. size of coarse aggregate
- 7. • Spacing of longitudinal bars shall not exceed 300mm from the periphery of the column • in our site they provided rectangular and circular columns • For rectangular column • -distributed the reinforcement equally on four sides
- 8. • - the no. of bars in a column are varying from 10, 12,14, 16, of varying diameter • They provide different diameter main bars i.e., 16mm,20mm,25mm • In our site 450mm dia. circular column Is used • For circular column they provide 6 nos 20mm dia. And 6 nos 16mm dia • The effective length provide is 48 times the dia . Of bar
- 9. TRANSVERSE REINFORCEMENT • In order to maintain the position of longitudinal reinforcement and also to prevent their buckling which may cause splitting of concrete. It is also assist confining the concrete • The diameter of transverse reinforcement shall not be less than 1/4th dia. of main bar in no case less than 5mm • The spacing of lateral ties the least lateral dimension of the column/16times the dia. Of main bars max spacing is 300mm
- 10. • In our site they provided lateral ties of diameter 8mm at a spacing 200 and 250mm c/c