A Lap is required when two pieces of reinforcing bar (rebar) are overlapped to produce a constant line of rebar. The length of the lap fluctuates according to the concrete strength, the rebar grade, size, and spacing. The objective of lap is to transmit load from one bar to another bar as well as retain continuity.

Why lap length is provided?

lap length is required when bars placed short of their required length (due to nonavailability of longer bars) need to be extended. lap length is to be provided to safely transfer the load. Development length is provided to transfer the load from steel to concrete. It is also known as anchorage length.

Why do we need overlapping of reinforcement?

The purpose of overlapping length is to retain the continuation of the steel bars to securely transmit the load from one steel bar to another bar. To securely transmit the load one bar is overlapped with another steel bar and length of smaller length of bar is taken as lap length.