Cross Section interpolation


I have Bridge with a cross-section of 4 “t” shape (TTTT) and the thickness of flanges and webs have certain value at support and decrease while moving to the midspan.

When i draw a structural line with start section (large thickness) and end section (Small thickness[midspan]), SOFiSTiK show me and error message saying that interpolation must be done in identical section. so how can i solve this problem?


I did it with adding variables on the axis at the stations in which the cross section has changes. And when I was modeling the cross section , I used cartesian references for the points of the cross section that needs to change their coordinates.

Kind regards

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In order to interpolate a cross-section properly, the two outer sections need to be structural ident. In your case, that means you need to check the cross-section points (in the result viewer or directly in SOFiPLUS(-X)). Make sure that the points of the two cross sections are named identically.

Here’s a short example project:
Querschnittsinterpolation.sofistik (33.2 KB)
Querschnittsinterpolation.dwg (52.5 KB)

Another way to solve variable flange height, as @sofijahris said, is to use variables.
If you need more information, please visit our website and watch the following tutorial. > Infocenter - Overview > Documentation - Tutorials > Bridge Design > Balanced Cantilever Bridge

For a general introduction to computer-aided bridge design, see our online bridge design training course.

Best regards
Frederik Höller
Your SOFiSTiK Support Team

Thank you for your reply

I tried to Make sure that the points of the two cross sections are named identically. but also the error still appears. Does this because the sections are not standard ones ?

but the variables approach worked

make first one section → then copy it → open copy → modify second section without adding new element, deleting old element, just change size of existing elements. it’s best way

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