Cold formed steel beams under monotonic and cyclic loading: Experimental investigation

The use of cold-formed thin-walled steel profiles in seismic structures is nowadays strongly penalized by code prescriptions, which impose for this kind of members a q-factor equal to 1, so that the design for the action of a severe earthquake must be carried out practically in the elastic field. On the other hand, some theoretical studies on the seismic performance of such structural systems gave encouraging results. For these reasons, an experimental and theoretical research program on the behaviour of cold-formed members loaded by cyclic loads has been started in the recent past by the authors. In the first phase of the experimental program, tests in bending on coupled channel beams under monotonic and cyclic load have been carried out. In this paper the research program is described, the obtained results are presented and some preliminary consideration is made on the behaviour of these types of members.