The situations is, that i have to find out, how much does other column helps (lenght is L1 in the picture) for others columns buckling (lenght is L).
There is a situation shouwn in a picture 2, where are two columns connected with a horizontal element in the top. It would be the same, if i connected column's (lenght L) top with a spring (spring stiffnes is 10500 kN/m) that columns could only move and there will not be rotation, like it is shouwn in picture 2.
Thank you!