Recent advances in tubular joints experiments in Brazil

Abstract

Dedicated to Prof. Dr.‐Ing. habil. Joachim Lindner on the occasion of his 80th birthday The aesthetical and structural advantages of tubular structural elements sustained the increase in their use in Brazil in last decades. The joints between tubular members remain a critical issue, with many studies indicating that further research is still needed, particularly for some geometries. In the past, some experiments on the influence of the chord stresses over the brace load capacity were published, but a definitive answer to this design issues was not reached. The first part of this paper presents an experimental evaluation centred on the effect of tension and compression chord stresses over RHS chord to SHS braces T‐joints. The results showed that compressive chord stresses could considerably reduce the joint resistance. In contrast, when tension chord stresses are applied the joint resistance increases but this is still not considered in the design codes. Still considering the tubular joints structural behaviour, there are cases where the ultimate resistance of the tubular joints may be enhanced by using flange plates as reinforcement, instead of replacing the chord or braces with stronger sections. Bearing this scenario in mind, the second part of this paper presents some experimental results of SHS T‐joints reinforced with flange plates to achieve a more economical design. The results showed that the joint resistance could be increased about 88 % using the reinforced plate with the same thickness of the chord profile.

Numerical Investigation of Doubler Plate Reinforced Tubular T‐joints under Chord Compression Loads

“…It should be noted that the Lima et al [4] formulation presented values major to those obtained in the numerical models. Onde again, it is necessary to mention that the parameter used by the authors to validate the equation is not applicable for the studid cases because the thickness doubler plate studied in this paper is not equal to chord one.…”

“…The second study [5] is directed related to the influence of the thickness doubler plate on the T-joint's structural behaviour, differently from the first one. The following equations presented the two proposals developed by Lima et al [4] and Souza [5], respectively.…”

“…In order to improve the comparison of the numerical results, two formulations were also selected. The first one corresponds to the study of Lima et al [4], where experimental and numerical analyses on T-joint with doubler plate were carried out. In this case, the authors did not perform a variation of the doubler plate thickness.…”

Numerical assessment of stainless steel tubular T‐joints subjected to brace and chord axial forces

“…A further experimental investigation will be performed in the laboratory to better understand the austenitic stainless steel tubular T-joints subjected to chord axial forces. For carbon steel, some experimental evidence from previous research conducted by the authors of the present paper has shown that the design rules for T-joints with chord axial effects are not adequate and need to be modified [16], [17].…”

Experimental and numerical assessment of CHS-RHS T-joints with chords subjected to axial tensile forces

“…Thus, other recent studies (Kim and Lee, 2020; Lima et al, 2018a; Nizer et al, 2016) have shown that, depending on the intensity of tension stresses in a chord, an increase in joint resistance could occur, what was never found in compression cases. For cases with compression stresses, the brace-to-chord ratio was identified as a critical parameter that influenced the joint strength of T-joints with reinforcements (Chang et al, 2020).…”