I am comparing the flexural buckling design according to the equivalent member method and the internal forces according to the linear static analysis with the stress calculation according to the second-order analysis, including imperfections. The differences are very large. What can be the reason for this?

Question

Accepted Answer

While the influence of imperfection increases significantly with increasing axial force and the ratio increases exponentially in the case of the second-order analysis, the influence of imperfection only increases linearly in relation to the axial force in the case of equivalent member design. Therefore, there is usually a greater difference between the design ratios according to the linear static analysis using the equivalent member method and the second-order analysis using the stress analysis for the structural systems with a very high or very low design ratio.

Differences in Flexural Buckling Design: Equivalent Member Method vs. Second-Order Analysis