Why there are several internal forces commands in SCIA Engineer and what are the differences between them?

SCIA Engineer offers 3 options how and where to display internal forces on concrete members. This FAQ explains why there are so many options and what is a difference between them…

Internal forces from FEM database

There are “clean” internal forces from FEM analysis. They aren’t adjusted and you can display them independently on the material. You can find them in Results > Beams > Internal forces on beams.

Fem database


Internal forces in concrete menu

In concrete menu you can display internal forces in Concrete > Reinforcement design > 1D members > Internal forces

These internal forces are used for reinforcement design. For reinforcement design, program needs a ration of longitudinal reinforcement and concrete area. Because of the reinforcement isn’t designed yet, the ratio is 2% by default and user can change it in the Concrete > Concrete settings > Solver setting > Internal forces > Internal forces ULS > Estimation ratio of longitudinal reinforcement for recalculation internal forces in design of reinforcement

Estimation ratio

Internal forces in concrete menu can be adjusted by reduction of shear force or moments above supports. These options are off by default and user can turn them on in the Concrete settings directly bellow Estimation ratio of longitudinal reinforcement.

Reduction of internal forces

*For above mentioned, the advanced mode of concrete settings must be turned on.

All that has some impact on the final reinforcement amount and thanks that you can reduce the project cost. 

Reduction of shear forces    Reduction of the bending moment    Influence of reduction of bending on reinforcement calculation

For concrete checks of 1D members is taken real using reinforcement. There is basically a small difference between internal forces in checks and in reinforcement design where above mention ration is taken into account instead of real using reinforcement. User can display these internal forces in Concrete > Reinforcement check (ULS+SLS) > 1D members > Internal forces