Allowing for member imperfections
Allowing for member imperfections (ACI/AISC)
AISC indicates that these are inherently catered for in the strut design.
For concrete design to ACI 318-11 there are no requirements.
Allowing for member imperfections (Eurocode)
For steel structures designed to EC3, member imperfections are intrinsically included in the design routines for all members (beams, columns, braces). Apart from one explicit requirement, carrying out the design is all that is necessary.
The explicit requirement is from Clause 5.3.2 (6) in which member imperfection should be included as part of the analysis when the frame is sway sensitive and the axial force in members with moment connections is above a certain limit. If this situation arises Tekla Structural Designer issues a warning.
For concrete structures designed to EC2, explicit calculations which consider an imperfection effect are carried out as part of the design.
In Tekla Structural Designer this is achieved by adding an additional moment to the analysis results before starting design.
Allowing for member imperfections (BS)
BS5950 inherently caters for member imperfections in the strut design curves.
BS8110 does not have a requirement (minimum eccentricity is not the same thing).