A group of reinforced bars, parallelly set to each other to act as a unit should be limited four in a bundle used as reinforcement in reinforced concrete, enclosed by stirrups or ties. Bars greater than 32mm should not be bundled in beams.
The development length of every bar of bundled bars should be that for the individual bar, increased by 10 % for two bars in contact, 20 % for three bars in contact, and 33 % for four bars in contact.