Additional tensile forces caused by shear and torsion (shifting of bending moments)
Additional tensile forces caused by shear and torsion is taken into account in Concretein SCIA Engineer by using simplified calculation based on shifting of bending moments according to clause 9.2.1.3(2). Shifting of bending moment is calculated only for beams and beams as slab.
Distance for shifting is calculated for both axes and depends on the type of member
- for beams
a = z ∙ (cot(θ) - cot(α)) / 2
- for beams as slab
a = d
where
| z |
is inner lever arm of cross-section z = Coeffz · Coeffd · h(b)
|
| d | is effective depth of cross-section d = Coeffd · h(b) |
| Coeffd | coefficient for calculation effective depth of cross-section "Coefficient for calculation of effective depth of cross-section" |
| Coeffz | coefficient for calculation inner lever arm of cross-section |
| h (b) | dimension of cross-section in centre of gravity of cross-section in z(y) direction in LCS of cross-section |
| θ | angle between the concrete compression strut and the beam axis perpendicular to the shear force "Angle between concrete compression strut and beam axis" |
| α | angle between shear reinforcement and the beam axis perpendicular to the shear force |
Automatic calculation of angle between the concrete compression strut and beam axis is calculated by simplified method for shifting with the following simplifications:
- shear of member for calculation value VRd.max is calculated as minimum width of cross-section at whole cross-section perpendicular to direction of shear forces
- value Ak and uk for calculation of TRd.max is calculated for effective rectangular cross-section, which has the same cross-sectional area and same perimeter as inputted cross-section