Built-up cold-formed steel elements are efficient structural elements, very attractive due to material savings, but also for ease of construction. The project proposes to investigate a new technological solution for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by economical and effective spot welding. In order to optimize the arrangement of the spot-welding connections, and to optimize detailing, analyse and evaluate the performances of proposed solution, the extensive numerical investigation is planned. The focus of the proposed project is calibration and validation of the numerical models based on experimental tests of such elements which will be followed with parametric numerical studies. Experimental tests with web openings in beams will also provide basis for parametric studies in case of application in floor systems of multi-storey buildings. The parametric studies will also evaluate the suitability of the analysed elements, for larger spans in case of frame structures, as alternative to purlins or secondary beams in case of single-storey buildings. All accumulated knowledge will be base for detailing, including possibility for mass production. Analyses and evaluation of the performances of proposed solution will be crucial for establishing analytical proposal for design recommendations for this new type of beams within the European standards. The proposed solution is made of cold-formed products which use only recyclable steel, and the system has the potential for future re-use and recycling. System is durable under climate change effects and in aggressive environment since all components are galvanised. It is easy to manipulate, transport and erect the system components because of the reduced weight and safe connection technology. Together with the knowledge gained in this project for Croatian science and the engineering society, the project also benefits Croatian industry because proposed solution has great potential for mass production.