05.24: New interaction formulae for sensitive structures to the second order effects

Abstract

Eurocode 3 Part 1-1 [1] gives a method to calculate the design criterion of a structure without include the imperfection in the model structure. This criterion enables to take into account the imperfection mainly with the buckling coefficient χ. However, we can highlight that the results obtained with this criterion (interaction formulae for beam-column) are overestimated compared to the results obtained when the imperfection where included in the model structure. This difference comes from the coefficient χ which is overestimated. In order to overcome this problem, a new coefficient definition has been established in order to take into account the imperfection in the calculation without include it in the model structure. This new coefficient enables to take into account the charge level of the structure. First, vertically loaded structures have been studied. Then the study is extended to the vertically and horizontally loaded structures. The study results are more close to the actual results. Thus, this new coefficient enables to substitute for the establishment of an initial imperfection both a safe and a reasonable assessment of stress rate.