Estimation of maximum admissible precambering of steel beams

Precambering of steel beams is a common process in construction to induce cold or heat deformation (parabola) to compensate for the deflections due to permanent dead loads and a fraction of a live load. However, the maximum allowable cambering (and consequently the minimum radius of curvature) before buckling of the element is not simple to be defined as it is dependent on the straightness of the beam and on the adopted cambering procedure. The main objective of this study is to describe and validate a numerical procedure (validated with experimental tests of beams with and without holes in the web) to properly assess the maximum load allowable. This numerical analysis was conducted including non‐linear material and geometrical imperfections (GMNIA). The effect of the magnitude of the imperfections as well as the impact of the distance between consecutive load application points have been considered and discussed.