Column base-plates under biaxial bending moment

This paper investigates the behaviour of exposed column base-plates with four outer anchor bolts subjected to monotonic loading. The results of six full-scale tests on steel column base-plate connections subjected to uni/ biaxial bending moment are presented. The influence of the base-plate thickness and the bending moment axis orientation on the connection response is thoroughly investigated. In addition to standard measurements, Digital Image Correlation has been used to closely monitor the evolution of the contact area that develops in the tensile and compressive zones. Furthermore, a detailed finite element model has been developed using the software Abaqus and used to explore additional orientations of the bending moment axis. This numerical model allows to investigate the evolution of the anchor bolt forces, the contact pressure distribution and the lever arm, that strongly influence the bending resistance and rotational stiffness. An Analytical model is suggested for the calculation of the bending resistance of a column base-plate connection whatever the orientation of the bending moment axis. The position of the centre of compression directly depends on the base-plate thickness. A plastic redistribution is also considered between the anchor bolt rows when biaxial bending moment is applied to the column base-plate.

Automated summary

This paper investigates the behavior of exposed column base-plates with four outer anchor bolts subjected to monotonic loading through six full-scale tests. The influence of base-plate thickness and bending moment axis orientation on connection response is thoroughly studied and an analytical model for bending resistance calculation is proposed. The experimental data and numerical model findings can provide a deeper understanding of the working mechanism of the connections.