- Select the bar(s) you want to define as compression bar(s).
- Click on .
- Select ‘Function’ next to ‘Nx’ and click on .
- Compression is negative, tension is positive. So define a function for which applies: if F<0 (= compression) then the bar can resist it (=fixed) and when if F>0 (= tension) the bar can’t resist is (= free). But because ‘Free’ is the equivalent of 0kN, it’s recommended to enter a very small value like 0.001kN. Calculating with 0kN migth give iteration problems.
- Select the function for the other end of the bar.
- Set the bending moment My’ and Mz’ free.
- The countarpart of a compression bar is a tie rod.