The lap rebar splice is the most common and economic rebar splice used in the construction project. Compared to lap rebar splicing, the welded rebar splices and mechanical rebar splices require more labor and skill.

The important points to be noted while providing lap rebar splices in reinforcement bars:

Laps splice in reinforcement should always be staggered. The center to center distances of laps should not be less than 1.3 times the required lap length of the bars. The bars to be lapped should be provided either vertically one above the other or horizontally one beside the other.

The total lap length of bars including bends, hooks, etc. in flexural tension should not be less than 30 times the diameter of the bar of the full development length Ld as calculated, whichever is greater.

Lap length in direct tension should be 30 times the diameter of the bar or 2 Ld whichever is greater. Tension splices should be enclosed in spirals made from 6mm bars with the pitch not more than 100mm. Hooks are also to be provided at the end of the tension bars.

Lap length is compression should be more than 24 or Ld in compression. When columns are subjected to bending, lap length may be also increased to the value in bending tension if the bar is found to be in tension.

When two different diameters of bars have to be lapped, the lap length should be calculated based on the diameter of the smaller bar.

Lap splicing of a reinforcement bar more than 36mm in diameter should be avoided. In case such bars have to be lapped then they should be welded. When welding of cold bars is allowed, the special instructions applicable to these bars should be followed.

Where the lapping of reinforcement bars have to be done in unusual circumstances such as splicing in areas of large moments or more than 50% of the bars have to be spliced, additional closely spaced spirals should be provided around the lapped bars and the length of the lap should be increased.

When bundled bars are to be spliced by lapping, one reinforcement bar at a time is to be spliced and the splicing should be staggered.

If the general rules regarding laps cannot be obeyed in construction, specially welded splices or mechanical connections should be provided.

The use of lap splices will cause splice congestion issues that will demand some other splicing method. Congestion of rebars will create critical stress points in rebars, the difficulty for concrete to pass through, the splice length would be insufficient.