Within the WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, a new technological solution was proposed for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by spot welding. The research project integrates an extensive experimental program on such beams, using full scale specimens, to demonstrate the feasibility of the proposed solutions and to assess their performance, followed by numerical simulations to characterize and optimize the connecting details. The present paper presents the results of a large experimental program, on small specimens subjected to shear, consisting of two or three layers of steel sheet connected by spot welding.

Corrugated web girders emerged in the past two decades. Their main advantages consists in the possibility to use slender webs avoiding the risk of premature local buckling. Consequently, higher moment capacity might be obtained increasing the beam depth with really thin webs, which are stiffened by the corrugations. Increased interest for this solution was observed for the main frames of single-storey steel buildings and steel bridges. A new solution was proposed at the Politehnica University of Timisoara, in which the beam is composed by a web of trapezoidal steel sheet and flanges of back-to-back lipped channel steel sections. This solution uses self-drilling screws for connecting flanges to the web and to ensure the continuity of the web as seam fasteners. Starting from this new technological solution the paper extends and investigates the use of spot welding as seam fastening to build the web, in order to increase the degree of automation of fabrication. Experimental work of specimens in shear having two or three layers of steel sheets connected by spot welding will be presented. The results will be implemented on a numerical model in order to study the behaviour of the beams presented above.

This paper summarized the research work carried out by a team from Department of Steel Structures and Structural Mechanics, together with Department of Materials Science and Engineering, from University Politehnica Timisoara, which tried to determine the possibility to use welding for obtaining built-up cold-formed steel beams made of corrugated galvanized steel sheets (grade S350GD+Z). There were analyzed two joining processes: MIG brazing and Resistance Spot Welding with the aim to replace the self-drilling screws used until now. The results are very promising and these solutions of joining have beside economic advantages also technical and quality ones.

The paper presents the results of researches carried out by a joint team from Department of Steel Structures and Structural Mechanics, together with Department of Materials Science and Engineering, from University Politehnica Timisoara, focused on the possibility of creating built-up cold-formed steel beams made of corrugated galvanized steel sheets by resistance welding, which will replace the similar beams built by self-drilling screws. Resistance spot welding technologies were developed and tested, together with mechanical testing of the welded joints, which were performed in our laboratories. The results obtained and presented confirm the good quality of the welded joints and, as a result, the good capability of this technology to be used in production, to replace the old type of beams.