RE: Buckling Analysis and Effective length

Dear Team 

I am working with the Staad model for buckling analysis . The buckling load factor is given by the staad after the analysis , wanted to understand the how to manually check the Buckling load factor using Critical Euler equation . I have manually tried for finding the effective length from the buckling load factor , the manually calculated effective length and Staad show node to node length from the buckling modes are not matching for the gravity load . Please helps to find the effective length from the staad any option available.

G+6_2000_2700_2500_Z3_Buckling Analysis .STD