Very different shear reinforcement from Torsion (CONCRETE)


Here is the main problem. I figured out that selection of, in this example, Concrete circular cross section (one is generic so called “standard section”, other is made in “New solid section-> Reinforeced concrete”), hugely influence on result in shear reinforcement design on Torsion.

Because of this, i made model with two separate columns (same cross section D=100 cm, but different way of input, standard seciton/New solid section), loaded with same Torsional moment, lets say, 675 kNm. Difference in shear reinforcement is huge, and i thought it must be same. Standard cross section gets roughly 97 cm2/m, and “New solid section” gets around 35 cm2/m. When i calculate by hand, i get around 25 cm2/m.

When i deep dive in Report of result, in both cases, it says that, Trd,s (of steel) is exact to 675 kNm, but Trd,C (concrete resistance) has huge difference (new solid section has around 2130 kNm for “standard section” 726 kNm). I used ctg=1 (angle is 45 degrees due to seismic).

Either way, result in shear reinforcement is huge. I dont get it, because, Trd,S steel is same for both cases and result shoud be the same. I dont have other forces in model.

Kind regards,


Could you please post the two simplified projects?
Are the two cross-section exactly the same? Have you also compared the individual cross-section values?

Best regards
Frederik Höller
Your SOFiSTiK Support Team