The design of continuous reinforced concrete slabs is a routine item-moments are taken from CP114 Table 15 or CP110 Table 4 (according to taste), reinforcement is calculated and it is then placed according to normal detailing practice: it is customary to stop off top reinforcement at 0.25 L or 0.3 L from a support (L = span).
Yet, as Beeby has pointed out in a recent paper3, this situation contains a paradox. Both Codes specify similar theoretical rules for curtailing reinforcement-e.g. CPllO cl. 184.108.40.206: ‘ . . . every bar should extend, except at end supports, beyond the point at which it is no longer needed for a distance equal to the effective depth of the member, or twelve times the size of the bar, whichever is greater. . . ’.