Experimental and numerical analysis of three-dimensional semi-rigid steel joints under non-proportional loading

This paper focuses on the study of a type of three-dimensional joint that consists of extended end-plates for both major and minor axes. The minor axis connections are bolted to a plate welded to the column flanges (additional plate). An experimental and numerical investigation on the proposed joint is carried out in order to obtain the rotational behaviour (moment–rotation curve) of different three-dimensional configurations, as well as to evaluate the interaction between both axes.Experimental and numerical results show coupling effects between major and minor axis joints. The minor axis load stiffens the tension zone of the mayor axis joint and makes the compression zone more flexible. This leads to a slight increase in the initial stiffness of the major axis joint. The numerical results reveal that the additional plate stiffens the major axis joint significantly.

► Three-dimensional semi-rigid steel joints under non-proportional loading are studied.
► Experimental tests and numerical models of this type of joints have been performed.
► The additional plates stiffen significantly the major axis joint.
► EC3 and Faella formulas are modified due to the additional plate, for these joints.
► EC3 underestimates the resistance of the studied joints.