Local imperfections represent manufacturing deviations in the form of equivalent loads. Corresponding regulations can be found in the standards: For example, EN 1993-1-1 Figure 5.4 shows the application of pre-deformations by means of horizontal equivalent loads; AISC 360-16 Section C2.2b describes the use of "notional loads" as loads to be applied laterally.
Local imperfections can be defined only for members and sets of members, but not for surfaces.
