Comparison of Geometrical Imperfection Definitions on Encased Composite Columns

The imperfections stemming from manufacturing or construction practices have effects on capacities of structural columns. Bow imperfections or residual stresses are commonly investigated and well known examples of these imperfections. Since the composite construction generally has different stages than reinforced concrete or steel construction, there are other sources of imperfections for this field. Different approaches to consider geometrical imperfections are studied for this paper. These are namely the approach of EN‐1992‐1‐1 [1],EN 1994‐1‐1 [2] and EN 13670 [3]. Eurocode 2 and Eurocode 4 specify geometric imperfection for columns differently. Former introduces them as load eccentricity and latter introduces them as bow imperfections. EN 13670 giving the construction tolerances for reinforced concrete structures, has different methods to limit geometrical imperfections. For the purpose of comparing different approaches and their effect on capacity calculations, several composite columns were simulated using physical and geometrical non‐linear analysis, their load‐deflection relationships were monitored and capacities compared. An outlook of the ongoing investigation for the adaptation of geometrical imperfection for composite columns is further discussed.