Structural class following the EN Eurocode recommendation
Eurocode 2 part 1-1: Design of concrete structures 18.104.22.168 (5) - Table 4.3N
The recommended Structural Class (design working life of 50 years) is S4 for the indicative concrete strengths given in Annex E (see § E.1 (2)) and the recommended modifications to the structural class is given in Table 4.3N - § 22.214.171.124 (5). The recommended minimum Structural Class is S1.
This application calculates the Structural Class (EN) from your inputs.