Prestressing Loadcase into Load combinations

SOFiSTiK
1

Hi everyone!
I was just hoping someone could help with this query, I have been working on a bridge model and have has to add prestressed tendons into the longitudinal beams. I have a seperate loadcase for the prestressing and now have to combine this with other loads i.e live loads, dead loads and wind loads.
I have tried using the “combined loads” and the “analysis of combined loads” for this task however, it is saying that there is no loads defined for my prestressing loadcase.
For example, the self weight loadcase looks like this,

self weight
self weight1302×478 86.3 KB

and the prestressing loadcase looks like this
prestressing
prestressing1311×447 75.1 KB
.
However when I combine these two loadcases only the selfweight is added to the combination,
any help with this would be great!!

2

Hello

This behavior is strange. Have you checked whether the prestressing loads are applied in the combined load case?

Graphic > Loads > Input Loads > All Loads > Select combined loadcase

How did you generate the prestressing forces?
Did you follow the same steps as outlined in our online bridge design tutorial?

Apart from that you can use the CABD Tasks in the SSD for supperpositioning bridge loads.

Best regards
Frederik Höller
Your SOFiSTiK Support Team

4

Hi Fredrerik,
I have created tendons in sofiplus using spline geometry and added them to a curvature loadcase.

image
image1274×686 58.5 KB

However when I try to add this loadcase into any load combination, it simply does not add the curvature load case.
I have also tried the CABD superpostitioning but it says that the tool is not supported within my desing code

5

Please watch the video series I sent you.
The tutorial describes all aspects of the workflow for a prestressed concrete bridge.

I assume you didn’t calculate the construction stages with the “construction stage manager”?
Before you compine the loadcase results you have to analyse the prestressing behaviour with the construction stage manager.

6

I have now carried out the construction stage task however I am unsure on how to get the prestressing behaviour into the load combinations, as I have various traffic and wind scenarios to analyse