Approaches to the Mechanical Properties of Threaded Studs Welded to RHS Columns.

Ismael García,Fernando L Gayarre,Miguel A Serrano,Jesús M Suárez,Carlos López-Colina

doi:10.3390/ma14061429

Abstract

The use of Rectangular Hollow Sections (RHS) as columns in steel construction includes important advantages like higher mechanical strength and fire resistance. However, the practical demountable bolted joints between beams and columns are not easy to execute, due to impossibility of access to the inner part of the tube. The use of threaded studs welded to the face of the tube and bolted to the beam by means of angle cleats is one of the cheaper and most efficient solutions to obtain beam–column joints with a semi-rigid behavior, as is usually sought in building structures. Nevertheless, it is important to point out that the stud-diameter and the stud-class selection may affect the mechanical properties of the welded parts of the joint. In this paper, 8MnSi7 (with a commercial designation K800) and 4.8 threaded studs were welded to RHS steel tubes and mechanical properties on the weld, the Heat Affected Zones (HAZ), and the base metal were obtained in two different ways: through a correlation with the Vickers hardness and by means of the Small Punch Test (SPT). A study of the microstructure and tensile tests on the threaded studs and in the columns was also carried out. The research involved different types of stud qualities, tube wall thicknesses, and stud diameters. The work presented in this paper proved that in most cases, the welded joint between these studs and the RHS steel tubes present a reasonable static behavior that fulfils the requirements for the beam–column joints under static loading.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
From the results it was inferred that zone 3, which corresponded to the interface between the stud and the tube, reached a higher maximum load with a lower maximum displacement than zone 2 and zone 4
Stud class 4.8 showed a similar maximum value of loading but a different maximum value of displacement in zones 4 and 5. This phenomenon was not observed in K800 studs, where a lower force for zone 4 was obtained, except for T8

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Steel building construction has traditionally chosen open steel sections such as I or H-profiles as beams and columns. The use of structural hollow sections as columns shows advantages like their mechanical strength, fire resistance, maintenance costs, aesthetics, and the possibility to create composite columns and making better use of space. Most of the beam–column joints between Rectangular Hollow Sections (RHS)

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Discussion

Conclusion