Section 4.3.5.2 Design tensile stresses in flexure (Transfer)
For beams and one-way slabs, tensile stresses in concrete, based on the concrete section, are limited to:
Class 1: 1 N/mm2
Class 2: .
Class 3: .
For Class 2 and 3 beams and one-way slabs, where the stresses above are exceeded, bonded reinforcement is provided as follows [TR 43, 6.10.2/6.10.5]: As = Fi / (0.625fy)
For two-way slabs without supplemental untensioned reinforcement, tensile stresses in concrete, based on the concrete section, are limited to 0 in the support region and in the span region [TR 43, 6.10.2].
For two-way slabs with supplemental untensioned reinforcement, tensile stresses in concrete, based on the concrete section, are limited to . Bonded reinforcement is provided as follows [TR 43, 6.10.2/6.10.5]:
As = Fi / (0.625fy)
For sections with multiple concrete mixes, the minimum fci is used to determine the limit stress and the peak stress reported may be approximate.
No check is made to ensure the cross section is post-tensioned.
Two way slabs can never exceed , while there is no limit for beam and one-way slabs that are class 2 or 3.