A review of literature and code requirements for the crack width limitations for design of concrete structures in serviceability limit states

This paper includes a critical review of the literature related to design of reinforced concrete structures in the serviceability limit state (SLS), and attempts to tie the results to code requirements. The main attention is given to the so-called controllable cracks, defined as cracks due to imposed loads or deformations on hardened concrete or restrained volume changes in young hardening concrete that a structural engineer has the knowledge and tools to predict and control. It is suggested that more consistent procedures are introduced into the future SLS-design. It is found necessary to more clearly distinguish the crack width requirements for aesthetic reasons from durability and tightness reasons, and clarify the use of the term durability in the code text. The research leading up to current leakage prediction formulas and tightness formulas is questioned based on the literature review. It is discussed that a differentiation of the crack width through a cross section will facilitate a more consistent treatment and limitation of crack widths.