I am working on a suspension bridge. I run a form optimalization to get nearly zero displacement from permanent loading. After that I run non linear calculation for every load case (wind load case don’t find equilibrium here, but i only got warrning message). Next I determine the most unfavourable combination with maxima. And I would like to run non linear calculation for the most unfavourable combination but I got an error about “Equation system reports negative determinants”.
I don’t really know how to handle this problem.
Do you have any solution?