Hello Support team,
Would you please help me to clarify the following questions related to load history calculations to Eurocode 2:
1. when I create additional load combinations intended for load history calculations only, do I need to apply any 'design rule sets' for these combinations?
2. what concrete strength is used to calculate cracking moment? Is it fctm(axial) in accordance with table 3.1 or fctm,fl(flexural) in accordance with 3.1.8? Considering that the shrinkage induced stresses are taken into account in cracking moment calculations, I would assume that fctm,fl would be more appropriate.
3. can you please clarify what creep strain-time diagram is used for loading/unloading in load history calculations? is any portion of creep strain assumed to be recoverable?
4. do I understand correctly, that RAM concept always uses betta factor of 0.5 (formula 7.19, EC 2) with regard to tension stiffening? If that is correct, in my opinion this can lead to heavily overestimated deflection values of 'partially stressed' post-tensioned elements. For example, if we have a post-tensioned slab where quasi-permanent load combination (with balanced load) induces a bending moment in the midspan of the slab equal to 0.5Mcr, and the remaining short term live load induces additional bending moment equal to 0.51Mcr, so that the total bending moment in the midspan of the slab is 1.01Mcr. Is it appropriate to use betta=0.5 in this instance?
5. is stiffness of bonded reinforcement (both top and bottom) considered in deflection calculations? is it both user and program calculated reinforcement which is taken into account?
6. is it possible to see shrinkage induced stresses plots, separately from external and internal restraints?
7. when I define load history steps, and I want to add one more step at the beginning of load history, is it possible to insert that step without deleting the ones I have already created?