Effective depth of cross-section
The effective depth of cross-section is usually defined as distance of the most compressive fibre of concrete to centre of gravity of tensile reinforcement. In SCIA Engineer, the effective depth of cross-section is defined as distance of the most compressive fibre of concrete to position resultant of forces in tensile reinforcement. In relation of bending loading in SCIA Engineer is calculated the perpendicular projection this distance to straight line perpendicular to neutral axis (slope line plane of equilibrium), called d.
There are some exceptional cases, when effective depth is not calculated from plane of equilibrium:
- The most compressive fibre can not be determined (the whole cross-section is in tension)
- Resultant of forces in tensile reinforcement can not be determined (whole section is in compression)
- Equilibrium is not found
- Distance of the most compressive fibre and Resultant of forces in tensile reinforcement is lesser than 0,5⋅h
In this cases, the effective depth is calculated according to formula
d = Coeffd∙hl
where
If there are the most compressive concrete fibres with the same value of compressive stress, the fibre which is the nearest to straight line in direction resultant of bending moment and crossing the centre of gravity of cross-section, is taken into account for calculation effective depth.