Behaviour of cracked reinforced concrete beams under repeated and sustained load types

Using experimental results, the validity of Expressions 7.19 and 7.9 of Eurocode 2 (EC2) are examined. The additional damage within the tension zone caused by the repeated load types is not accounted for in either expression, meaning that the tension stiffening effect is overestimated. Consequences of this are that design code SLS (serviceability limit state) checks for beams with complex load histories may be inaccurate, and that the average steel stress within the reinforced concrete sections may be underestimated.