Rebar Lapping

[JackyLooi]

Hi All,

Can someone explain how rebar lapping works ?
I have 3 question to ask.
1) When lapping with 2 different size of rebar, the lap length shall be calculated based on smaller rebar. Why ? and what is the theory behind ?
2) When 2 different grade of rebar lap, the lap length have to design based on higher grade or lower grade ?
3) If X25 lap with H40, lap length have to design based on which bar ?

Need your professional explanation please. Thank you.

 

[hokie66]

I think you can answer your own question. If one bar is capable of, just for argument sake, 10kN, and another is capable of 20kN, what would be gained by lapping the bars to develop 20kN?

 

[Ron]

I don't do much with reinforced concrete; however, I see no good reason to mix grades of rebar in the same member. That's like measuring with a micrometer, marking with a crayon and cutting with an axe.