Stiffness Prediction of Connections between CHS Tubes and Externally Welded I-Beams: FE Analyses and Analytical Study

Abstract

<jats:p>Double-tee profiles are the most popular members in Europe and the USA for steel structures. However, more efficient cross-sections, such as circular hollow sections (CHSs), could be adopted, since they can provide higher aesthetic, economic and mechanical benefits, with the only drawback of more complex connections such as in the case of I-beams welded to the external surface of circular hollow profiles. Based on the ring model theory, developed by Togo, a rule to design the flexural resistance of such a connection has been included in the Eurocode 3 part 1.8, while no formulations are provided to predict the corresponding initial stiffness. The present work aims at filling this knowledge gap, adopting an approach based on experimental, numerical and analytical work. A monotonic and a cyclic test have been performed on two beam-to-column sub-assemblies; the experimental outcomes have been exploited to validate a finite element (FE) model developed in Abaqus and used to numerically perform the monotonic loading simulations of 30 joints. Afterwards, starting from the extracted information about stiffness, a regression analysis was carried out to define the coefficient of a design equation analytically derived applying the component method approach. The regression analysis is characterized by a coefficient of variation equal to 0.19.</jats:p>

Strength of Connections Between SHS Columns and Through Plates

“…Instead, concerning the mechanical response, this approach allows for obtaining connections able to provide higher strength and stiffness compared to the traditional solutions with the beams externally welded to the columns. This evidence has been proven by the LASTEICON project investigation [3][4][5] and studies carried out at the University of Salerno [6][7][8][9]. In particular, the research is still ongoing and has been developed according to the spirit of the component method approach [10,14].…”

“…The recent exploitation of 3D-Laser Cutting Technology (3D-LCT) in Civil Engineering has allowed the manufacturing of new welded beam-to-column connections characterised by tubular columns [1][2] and passing-through beams. An example of this solution is provided by joints between Circular-Hollow-Section (CHS) and through-all IPE profiles recently studied in the framework of the LASTEICON research project [3][4][5] and at the University of Salerno [6][7][8][9]. The manufacturing process consists in cutting the column according to the imprint of the beam so that it can cross the tubular profile; finally, the two members can be welded.…”

Strength of connections between SHS columns and through plates

“…Additionally, since this technology allows the adoption of smaller tolerances, there is the benefit of reducing the slag and the heat-affected zone (HAZ). Instead, from a mechanical point of view, 3D-LCT makes available connections able to provide higher strength and stiffness compared to the traditional solutions with the beams externally welded to the columns, as well-demonstrated in [3][4][5][6][7][8][9].…”

Flexural resistance of 3D cut welded joints between SHS columns and through I‐beams

“…During the last few years, much attention has been devoted to studying steel joints characterised by tubular columns [1][2] and passing-through beams, which can nowadays be manufactured thanks to 3D-Laser Cutting Technology (3D-LCT). An example that demonstrates the increasing relevance of this detail is provided by investigations on Circular-Hollow-Section (CHS) and through-all IPE profile connections studied within the framework of the LASTEICON research project [3][4][5] and at the University of Salerno [6][7][8][9]. This joint is characterised by a beam crossing the tubular profile that is appropriately cut according to a double-tee imprint.…”