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

Abstract 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.