Load combination resulted from TRAC command

Hi guys,

I want to create a load case resulting from combination of loads obtained by “TRAC” command in order to be used for steel buckling resistance verification later on! Using “TRAC” command I found and saved combination of loads under “CSAV 501” in Maxima module. Then, I created a new load case 68000 containing combination of loads 501 in Sofiload as follow:

However, I get the following warning message:

I checked! TRAC command worked properly.

I have also checked result of Load case 12001:

It seems that train load created by ELLA cannot be copied in the new load case! Does anyone have any solution, please?


the transformation of the load cases of a load case combination generated with TRAC … CSAV into loads in program SOFiLOAD is only possible, if the initial load cases have ‘real’ loads → hint in the manual MAXIMA record TRAC:

The transformation of load cases which are saved with CSAV into loads with SOFiLOAD is only possible for initial load cases which contain ’real’ loads. Initial load cases whose internal forces or other results are used in the superposition and which are not based on ’real’ loads are not considered whilst saving of the new combination. They get a warning in the program SOFiLOAD.

Following superposition results can not transformed into loads:

• Difference load cases from CSM construction stage (consideration in ASE with group control)

• Internal forces from modal analyses (workflow earthquake)

• Results from calculation of eigenvalues

• Results from calculation with time-step-method

This is also valid for the definition of dead loads with the factor of the structural dead weight in SOFiLOAD → LC 1 TYPE G_1 FACD 1.0. In this case a transformation into loads is not possible.

With kind regards
Sabine Fahrendholz
Senior Product Manager

Thanks Sabine for your response. I got however a warning message (shown in orange color) regarding LC 12001 in Sofiload, which is a train load created in ELLA module!

ELLA load effects are generated through influence lines.
Your results for a particular beam show a maximum internal force for each section in the beam, i.e. the load position is different for each section.

ELLA loadcases aren’t “real” loads either → no csav

Thanks @sfr sfr for your reply! Is there anyway to create a combination load that include load-cases created by ELLA module? I want to run BDK for a component of a truss bridge. To do so, I need to find combination load for load cases leading to maximum compressive normal force of the component. Maximum normal force for ULS saved under LC 2102. Using TRAC command, I found out that combination of the following loads leaded to maximum normal force in the member. However, I need to create the combination load to find out associated bending moment and etc. Then, I can examine buckling resistance of the member. Any suggestion is appreciated.

You don’t need TRAC for the associated internal forces.
Maxima combines for a certain max/min goal, but always yields all the internal forces for an element.

So if you check the other internal forces in the element for an LC (in your case LC 2102 and beam 10045), you get the minimum normal force and other accompanying forces for that beam section.

If you need the accompanying forces in neighbouring elements (i.e. the entire beam), you’ll probably have to extract the load placement from ELLA. You can use COPY in sofiload for that.

Thanks again @sfr. True, I can find accompany internal forces in the element for LC 2102 and do buckling check manually (calculation per hand). If I use BDK module in sofistik to calculate buckling verification (program-intern), I have to create a load combination.

I am wondering if I can create the load combination when one load case of the combination is computed by Ella. In my case, I should create a load combination containing the following load cases (including their factors):

I created the load combination as follow, but I did not get the same internal forces for the element 10045 (look at two last pictures). If it is not possible, then only hand calculation is possible for the verification here.