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Detailing of Beams
Bar Bending Schedule
Standard hooks for detailing:
The beams are classified as:
Typical drawing of a simply supported beam
- Beam carries transverse external loads that cause bending moment, shear forces and in some cases torsion
- Concrete is strong in compression and very weak in tension.
- Steel reinforcement is used to take up tensile stresses in reinforced concrete beams.
- Mild steel bars or Deformed or High yield strength deformed bars (HYSD) are used.
- HYSD bars have ribs on the surface and this increases the bond strength at least by 40%
Bar Bending Schedule
- Drawings generally include a bar bending schedule
- The bar bending schedule describes the length and number, position and the shape of the bar
- Anchorage in steel bars is normally provided in the form of bends and hooks
- The anchorage value of bend of bar is taken as 4 times the diameter of bar for every 450 bend subjected to maximum of 16 times the diameter of bar.
Standard hooks for detailing:
The beams are classified as:
- According to shape: Rectangular, T, L, Circular etc
- According to supporting conditions: Simply supported, fixed, continuous and cantilever beams
- According to reinforcement: Singly reinforced and doubly reinforced
- Minimum cover in beams must be 25 mm or shall not be less than the larger diameter of bar for all steel reinforcement including links.
- Nominal cover specified in Table 16 and 16A of IS456-2000 should be used to satisfy the durability criteria.
- Longitudinal reinforcement at tension and compression face.
- Shear reinforcements in the form of vertical stirrups and or bent up longitudinal bars are provided.
- While drawing the details of a beam following convention representation of bars are used
- Mild steel bars : ?; HYSD bars: # or
- Main bars are shown by thick single line.
- Hanger bars are shown by medium thick lines.
Typical drawing of a simply supported beam
