In this article toady I will teach you the difference b/w Lap length and development length so after reading this article you will be able about lap length and development length in detail.
In civil Engineering point of view the lapping length is also called overlapping length, and lapping length we can define when the steel in bar is not sufficient for the design length which we required, so for that we lap the other steel to complete the design length , so there two steel should be overlapping on each other that is called lapping or overlapping length.
Lapping length can transfer the load from on e member to other, and the reinforcement bar need to be firmly bind at both ends.
Example: If we have to place the steel on the slab and the length of the slab is 22 meter, And in the market there we have the steel length which is 12 meter so if we complete our design length for steel in slab so we have to over lap the other steel to complete our steel design for slab.
we have two kind of lapping in steel
Lap length for tension members = 40d ( Specially used for Beam )
Lap length for compression members = 50d. ( Specially used for Column )
The above formula you can use at site for practical construction work, Because this is the real design structure formula
Development length is the length of bar which we used to transferring the stress into concrete.
We used the given formula
Development length (Ld) =d x σs/τbd
d is Dimmeter of bar
σs = Stress in the bar at the section considered as design load.
τbd = Design bond stress.
written by: Engr Sami Ullah Stanikzai