Questions:

For imperfection, the initial imperfection in the analysis is assumed as 0.00x of the member length with reference to BS5950 (where x is the input value and 1 is recommended in the manual.) Does such approach equivalent to the required frame imperfection (H/200) and member imperfection (L/200-500) in Structural Use of Steel 2005??

Reply:

The member imperfection (L/200-500) is input in section definition tab while the frame imperfection (H/200) is input in “General Settings -> Nonlinear Parameters ->Imperfection Direction -> Eigen value”. In default, the member imperfection is set as HK Steel Code 2005 or Eurocode-3 (2005) if you change the default. The frame imperfection (H/200) should be calculated and input by users or by program which finds the maximum linear dimension to determine the imperfection.