Labor Guideline for Steel bars in RCC

Cement concrete is strong in compression but weak in tensile. For enhancing the strength in tensile strength, MS Steel bars are used and after using MS Steel bars in cement concrete than it is called as Reinforced Cement Concrete. In general steel bars are mild steel bars and deformed steel bars (Tor or ribbed steel bars)

Mild steel bars are used in slab; beam as tensile reinforcement and these bars have plain surface and round section. The other steel bars are cold twisted deformed steel bars and these bars have lugs, ribs or deformation on the surface of bar. These bars provided good bond with cement concrete and have less slippage. The tor or ribbed or cold twisted deformed bars are better than mild steel plain bars and  have more tensile stresses and also used without end hook.

There are various grades in Mild Steel bars. According to Indian Standard IS no 432 part-1 the Reinforcement bars   can be categorized into following types.   

• Mild Steel Bars: These steel bars can be further categorized in two grades
• Mild steel bars grade-I designated as Fe 410-S or Grade 60.
• Mild steel bars grade-II designated as Fe-410-o or Grade 40
• Medium Tensile Steel Bars designated as Fe- 540-w-ht or Grade 75

Guide Line for Labor

• Before bending and binding the steel bars, it should be ensure that the steel bars are free from rust, dust, oil, paint and mil scales etc. These impurities affect the bonding strength.
• If rust found on bars, should be clean by rubbing gunny bags and wire brush but not clean with oil.
• Crank in the steel bars should be give at proper place as per drawing and height should be according to size of beam or slab.
• Try to use bar in full length without lap, if not possible than overlap should be staggered.
• Ensure the length of overlap and should not be less than 50 d i.e. 50x diameter of bars.
• Use supports under the crank bars in slab to maintain height of the crank bars during laying of cement concrete in the slab.
• If steel bars are to be adjusted in two layers in beam than use spacer between the bars to maintain space for filling cement concrete.
• Ensure bars should not be disturbed during lying of slab.
• The steel bars more than 36 mm in diameter should be welded for overlap.
• Binding wire for binding steel bars should be twin and 4’’ in length.
• All the joints of steel bars should bind diagonally, some binder have practice to bind alternately which should be avoided.
• If plan mild steel bars used than provide hooks on the end of the steel bars.