Experimental Studies of The Back-To-Back Connected Cold Formed Steel Profile Bolted Joints

This paper presents the experimental test results of joints connecting the cold formed thin-walled steel profiles assembled in a pair, back-to-back cross section. The tests were carried on at the Faculty of Civil Engineering and Building Services from Iasi. In the first testing stage there were tested the joints of a frame structural model connected with high strength friction bolts. In the second stage, it was advocated the increase of the profile bearing capacity by introducing some supplementary elements at the flanges; the maximum stresses were expected there and occurred. The specimen is built and modeled as a simply supported beam. In the midspan it is constructed the joint that focuses the research interest. There the load is applied as a concentrated force. The tests were carried on in the quasi-static regime in several load-unloading cycles; in the last stage the load was increased until the model collapsed. The strengthening of the flange has not increased significantly the model stiffness, but the bearing capacity was increased with 20?35% depending on the profile type.