Steel Bars Over Lapping in Beams, Slabs, Columns
Lap length is one of the significant terms in the reinforcement. This is typically mistaken for another significant term called advancement length and anchorage length. During the placement of steel in a Reinforced concrete structure, if the necessary length of the single bar may miss the mark. To get the ideal plan length, the lapping of two bars one next to the other is finished. An option in contrast to this is to give mechanical couplers.
Why over lapping of steel is significant?
The overlapping of the steel is significant in R.C.C works since joining of steel is utilized to move all the worries starting with one bar then onto the next bar. The length of the lapping is diverse in various concrete mixes in light of the fact that distinctive concrete having an alternate smashing quality.
Notes to regard:
1. The lapping isn't given over 36 mm measurement bars in light of the fact that those distance across bars doesn't move the worries starting with one bar then onto the next bar and furthermore the arrangement of the column bar is additionally influenced by giving the lap on these bars.
2. The lapping of the steel bars likewise not given in high shear power zones and it ought to be given at that zone where the shear power will be least.
The lapping of Different Concrete Mix
M 15 Concrete Mix
In M 15 we utilize the concrete mix 1 : 2: 4 methods 1 piece of cement, 2 piece of sand and 4 pieces of aggregates.
Tension zone |
Compression Zone |
Fe 250 – 55 ∅ |
Fe 250 – 45 ∅ |
Fe 415 – 57 ∅ |
Fe 415 – 47 ∅ |
Fe 500 – 68 ∅ |
Fe 500 – 57 ∅ |
M 20 Concrete Mix
In M 20 we utilize the concrete mix 1: 1.5 : 3 methods 1 piece of cement, 1.5 piece of sand and 3 pieces of aggregates.
Tension zone |
Compression Zone |
Fe 250 – 46 ∅ |
Fe 250 – 37 ∅ |
Fe 415 – 47 ∅ |
Fe 415 – 38 ∅ |
Fe 500 – 57 ∅ |
Fe 500 – 46 ∅ |
M 25 Concrete Mix
In M 25 we utilize the concrete mix 1 : 1: 2 methods 1 piece of cement, 1 piece of sand and 2 pieces of aggregates.
Pressure zone |
Compression Zone |
Fe 250 – 39 ∅ |
Fe 250 – 32 ∅ |
Fe 415 – 41 ∅ |
Fe 415 – 33 ∅ |
Fe 500 – 49 ∅ |
Fe 500 – 39 ∅ |
Where ∅ is the breadth of the bar.
Let us assume that we are utilizing a steel bar Fe 500 and concrete mix M25.
The width of the bar will be 10 mm.
By utilizing the equation, the joint length of the steel bar will be 49 x 10 = 490 mm and if the bar is in tension zone and 39 x 10 = 390 mm if the bar is in the pressure zone.
So, that was the way to calculate the lap length of steel bars in overlapping steel bars inside columns, beams, slabs. Hope this was useful. Happy learning!