Context
Eurocode 2: Reinforced concrete - Checking serviceability limits

Service condition checks are defined by reference to stress limits, cracking limit states and deformation limit states.

When calculating stresses and deflections, sections should be considered as uncracked, provided that the tensile stress due to bending does not exceed a certain value f_ct,eff. For this, either f _ctm, i.e. $f_{\text{ctmfl}}$ on condition that the same value is used to calculate the minimum section of tensioned steel. When calculating crack opening and the contribution of tensioned concrete, f _ctm should be used.