BTW: this stuff of this topic is awesome ! We need to get this into FreeCAD result object ! I think it is of practical value and a great learning experience for me on how to write Python and integrate it with FreeCAD using the FC API. I am now trying to clean importToolsFem.py up and write a Macro ...

Did you combine beam and bars into BooleanFragments object with type turned to CompSolid?

Thanks Thomas. I will give it a try. Did you try to mesh this model?

@Harry: About prestressing. When you use straight prestressed rebars, you get a negative constant moment in the beam. You can compensate the max M (from selfweight/loading) in the middle of the beam, but at the end of the beams you have unnecessary negative moments. The rebars for prestressing shou...

Here is a testcase you can run. 8-m 2-field beam, loading self-weight and constant 20 kN/m. The static calculation was done with my commercial software. 2_field_beam_static_calculation.pdf 2_Field_Beam.FCStd testcase.JPG Thanks Thomas, that's an interesting one to test. Let me see what my FC routin...

Load Case 4 - Self weight + Pre-tension + Live load In a final step the effect of applying live load is considered. The maximum deflection under this load is 7.7mm, which should be compared to the 10.6mm without pre-tension. The stress in the cable increase further to 388MPa.. The required reinforc...

Load Case 3 - Self weight + Pre-tension In this and the next case the effect of pre-tensioning of the beam will be analysed - in particular the impact on the reinforcement ratios and shear/crushing failure of the beam. In this Load Case 3 the situation before applying live load will be considered. ...

Load Case 2 - Self weight + Live load (no pre-tension) This second case represents a simply reinforced beam without pre-tension. The maximum deflection of the beam for this case is 10.6mm and the induced stress in the passive cables is 162 MPa … they act as reinforcement bars. The required reinforc...

I spent some time exploring the application of the Reinforcement Ratio and Mohr Coulomb routines for concrete design. For this I analysed the beam of previous posts, with and without pre-tension. The dimensions and properties of the beam are as follows: Beam Dimensions : 4.0x0.3x0.1m Elastic paramet...

By the way, such a high reinforcement ratio will probably lead to (brittle) crushing failure at the top of the beam. That's why you also need to check a compression/shear criterion, e.g. Mohr Coulomb. That could come instead of a von Mises check, which has no practical application for concrete. Nex...