Question About Lapping Steel Calculation!!!!

I have slab of bridge and its rainforcement steel design shows 20% Lapping and 40D

Steel Lenght is 22,800 mm and width is 9300 so how can i set the lapping steel with very low wasteg

can anyone explain easy formula for this different cutting lenght of steel with zero wasteg of steel
 
I have slab of bridge and its rainforcement steel design shows 20% Lapping and 40D

Steel Lenght is 22,800 mm and width is 9300 so how can i set the lapping steel with very low wasteg

can anyone explain easy formula for this different cutting lenght of steel with zero wasteg of steel
cutting length will vary as per dia of the steel to compensate with min wastage. What is the dia of steel ??