LAUSR

Abstract This paper presents extensive experimental investigations of models of I-shaped steel columns with segmentally prismatically variable stiffness. The models are discretely braced with lateral restraints along their length. With regard to the geometry of the actual columns, the models were made on the semi-industrial scale of 1:2. An external load, in the form of a vertical concentrated force, was applied to the header (in the Ch test series) or to the bracket (in the Cb and Chb test series). Selected static equilibrium paths of the linear displacements and the angles of rotation of column cross sections, determined in each of the test series, are presented and their behaviour is described in detail. Moreover, in the case of the Ch3 and Cb3 models, stress intensity in selected cross sections is examined by means of electrical resistance strain gauges, and the increase in normal stress with regards to the external load is shown. In addition, the experimental investigations included relevant material studies to determine the strength and chemical composition of the steel of which the columns were made.