ANALYSIS OF WELDED CONNECTIONS BETWEEN THIN-WALLED CIRCULAR HOLLOW SECTION (CHS) COLUMNS AND I-SECTION BEAMS FORMED BY COLD-FORMED STEEL (CFS) PROFILES

Resumo

This study investigates the behavior of welded T-joints between thin-walled circular hollow section (CHS) columns and I-section beams assembled from cold-formed steel (CFS) profiles. The research addresses the absence of national and international standards specific to slender section profiles, which are widely used in Brazil due to milder environmental conditions. Numerical models were developed using the finite element method in ANSYS 18.2 and validated against experimental results from the literature. A parametric study of 36 models investigated the influence of three key parameters: tubular section slenderness (2γ), the ratio of beam flange width to column diameter (β), and the ratio of beam height to column diameter (η). The study included 16 models with beams formed by U-profiles and 16 with C-profiles, focusing on moment resistance and initial rotational stiffness. The results revealed that existing design formulations inadequately predict the behavior of these connections. Notably, beams with C-profiles demonstrated average improvements of 15.9% in moment resistance and 16.8% in initial rotational stiffness compared to U-profiles. These findings highlight the necessity for further investigations into welded T-joints involving thin-walled CHS columns and I-section beams. Additionally, the study underscores the structural advantages of employing C-profiles, which enhance both resistance and stiffness, contributing to improved overall performance.