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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.

Modern seismic design codes require that the seismic performance of beam-to-column connections in steel moment resisting frames be demonstrated through experimental investigations, which are expensive and time-consuming. A solution to this problem is the prequalification of typical connections for the design practice, which is common in U.S. and Japan. Recently concluded European research project entitled EQUALJOINTS (European pre-QUALified steel JOINTS) addressed the seismic prequalification of several beam-to-column connection typologies common in the European practice. The current paper outlines the experimental program performed on 24 bolted extended end-plate connections with haunches investigated at the Politehnica University of Timisoara in the framework of this project. The parameters of the experimental program consist of beam/column size, haunch geometry, joint configuration (single-sided and double-sided), panel zone strength, loading protocol (monotonic and cyclic) and beam over strength. The performance of the specimens is quantified in terms of deformation capacity, stiffness, and strength. Tests showed a satisfactory cyclic response, with plastic deformations occurring in the beam, at the end of the haunch. Consequently, extended end plate beam to column connections with haunches prove to be a suitable solution for seismic applications with large plastic deformation demands.

The WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, proposes to study 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 resistance spot welding. Within the research project, the experimental work includes tensile-shear tests on the lap joint spot-welded specimens, were different combinations of steel sheets with various thicknesses were tested and, tests on full scale beams in bending. The study intends to demonstrate the feasibility of the proposed solutions, to assess their performance and to enlarge the knowledge by using numerical simulations for the optimization of the current solution and to define the limits of the solution’s applicability.