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Maximum crack spacing in the calculation of crack width: the values of k3 and k4

Eurocode 2 part 1-1: Design of concrete structures   7.3.4 (3)

The maximum final crack spacing sr,max in the calculation of crack width (see § 7.3.4 (1)) may be calculated from Expression (7.11) in situations where bonded reinforcement is fixed at reasonably close centres within the tension zone (spacing ≤ 5(c + Φ/2)):

sr,max = k3 c + k1 k2 k4 Φ/ρp,eff (7.11)


The recommended values for k3 and k4 in the calculation of crack spacing are 3,4 and 0,425 respectively.

National choice