Because of their technical and esthetical advantages, beams with web openings have become more and more popular on the steel construction industry. This beams have different ruin modes than standard beams. Thus, many different calculation method have been proposed in order to predict analytically the resistance of such beams, especially for the ruins modes of Vierendeel mechanism and of Web-post buckling. The latter has been subject to numerous studies aiming to propose analytical model of the resistance load. This different models appears to be not efficient enough to predict the behavior of those beams, as it has been shown in previous studies. It is even more true when the beams are exposed to fire condition, as the properties of steel changes and buckling is much more likely to appear. The objective of the present work is to gain enough data to establish a new model that can be adapted to different geometrical configuration and openings types.

Previous works showed that the ruin mechanism of the web-post buckling is always follow by a ruin mechanism by Vierendeel flexion of the elongated opening. The present work aims to characterize the resistance of a web post between two openings, isolated so as numerical studies can be perform on an « Isolated Web-Post model ». The principle of this method is to work only on the web-post with particular constraint to simplify the number of variables. Changing the width, the thickness of the web post and the height of the openings, we will be able to find out if there is trend in the behavior of the web post, and then compare it to the behavior of the web-post in a complete beam model.

At first, this document aims to validate the representability of the « Isolated Web-Post model ». This model will then be used as a reference to characterize of the critical buckling load and the ruin load. This results will be used in order to improve the investigations on the analytical model. This experiment will be renewed for fire conditions. In order to do this, the FEM software’s SAFIR and CAST3M will be used.

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Accepted with Honours