Overstressing force during tensioning: the value of k3
Eurocode 2 part 1-1: Design of concrete structures 184.108.40.206 (2)
Overstressing is permitted if the force in the jack can be measured to an accuracy of ± 5% of the final value of the prestressing force. In such cases the maximum prestressing force Pmax (see § 220.127.116.11 (1)P) may be increased to k3⋅fp0,1k⋅Ap (e.g. for the occurrence of an unexpected high friction in long-line pretensioning).
The recommended value of k3 for the calculation of overstressing force is 0,95.