Do’s & Donot’s for Rebar Detailing

Do’s-General
  • Prepare drawings properly & accurately if possible label each bar and show its shape for clarity.
  • Prepare bar-bending schedule, if necessary.
  • Indicate proper cover-clear cover, nominal cover or effective cover to reinforcement.
  • Decide detailed location of opening/hole and supply adequate details for reinforcements around the openings.
  • Use commonly available size of bars and spirals. For a single structural member the number of different sizes of bars shall be kept minimum.
  • The grade of the steel shall be clearly stated in the drawing.
  • Deformed bars need not have hooks at their ends.
  • Show enlarged details at corners, intersections of walls, beams and column joint and at similar situations.
  • Congestion of bars should be avoided at points where members intersect and make certain that all rein. Can be properly placed.
  • In the case of bundled bars, lapped splice of bundled bars shall be made by splicing one bar at a time; such individual splices within the bundle shall be staggered.
  • Make sure that hooked and bent up bars can be placed and have adequate concrete protection.
  • Indicate all expansion, construction and contraction joints on plans and provide details for such joints.
  • The location of construction joints shall be at the point of minimum shear approximately at mid or near the mid points. It shall be formed vertically and not in a sloped manner.
Do’s – Beams & Slabs
  • Where splices are provided in bars, they shall be, as far as possible, away from the sections of maximum stresses and shall be staggered.
  • Were the depth of beams exceeds 750mm in case of beams without torsion and 450mm with torsion provide face rein. as per IS456-2000.
  • Deflection in slabs/beams may be reduced by providing compression reinforcement.
  • Only closed stirrups shall be used for transverse rein. For members subjected to torsion and for members likely to be subjected to reversal of stresses as in Seismic forces.
  • To accommodate bottom bars, it is good practice to make secondary beams shallower than main beams, at least by 50mm.
Do’s – Columns
  • A reinforced column shall have at least six bars of longitudinal reinforcement for using in transverse helical reinforcement for CIRCULAR sections.
  • A min four bars one at each corner of the column in the case of rectangular sections.
  • Keep outer dimensions of column constant, as far as possible, for reuse of forms.
  • Preferably avoid use of 2 grades of vertical bars in the same element.
Donot’s – General
  • Reinforcement shall not extend across an expansion joint and the break between the sections shall be complete.
  • Flexural reinforcement preferably shall not be terminated in a tension zone.
  • Bars larger than 36mm dia. shall not be bundled.
  • Lap splices shall be not be used for bars larger than 36mm dia. except where welded.
  • Where dowels are provided, their diameter shall not exceed the diameter of the column bars by more than 3mm.
  • Where bent up bars are provided, their contribution towards shear resistance shall not be more than 50% of the total shear to be resisted. Use of single bent up bars (cranked) are not allowed in the case of earthquake resistance structures.

 

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