Crack width control: verification of the deformation compatibility vs. covering the cracking force

According to the current design code the crack width control is provided by a minimum reinforcement covering any restraints as well as crack width verifications for the decisive load combinations, whereas the interaction of both is generally not pursued further. Almost all guidelines advise to control the crack width due to restraint by a minimum reinforcement taking up the cracking force respectively the cracking moment, e.g. [1] and [2]. However, such procedure neglects the deformation compatibility along the member length and the interaction of restraints and external loads is not pursued any further. Altogether, this can either lead to structural damage - mainly recognizable in form of leaking cracks in watertight constructions - or to inefficient constructions. A mechanical consistent crack width control under consideration of the real member behaviour can solely be achieved by the verification of the deformation compatibility since deformation compatibility is also the reason for restraints in the first place. Such procedure is shown for instance in [3] for the particular case of early age effects.