Nonlinear behaviour and design of stainless steel hybrid tubular K-joints with SHS-to-CHS

This paper presents a finite-element (FE) investigation on the bearing capacity of stainless steel hybrid tubular K-joints with square braces and circular chord. The nonlinear finite-element (FE) models were developed and validated against the test results available in the literature, which were then used to conduct a parametric study including 162 models. The parametric study results showed that the joint strengths of the stainless steel hybrid tubular gapped K-joints increased when the beta and tau values increased and when the 2 gamma and e values decreased. On the other hand, the joint strengths of overlapped K-joints increased when the H, T, and O-v values increased and when the 2 gamma values decreased. Furthermore, the bearing capacities obtained from the parametric study were compared with the design strengths calculated from the current design guidelines. The comparison showed that the current design rules of Chinese Code (GB 50017-2017) were generally un-conservative for stainless steel hybrid tubular K-joints. The coefficient of variations (COVs) obtained from the comparison of EC3 (2005), AS/NZS (2001) and GB 50017 (2017) were very large. However, the design strengths calculated from the International Committee for the Development and Study of Tubular Structures (CIDECT) were relatively close to the FE strengths. Therefore, modified design rules are proposed in this paper. New design formulas were developed by applying correction factors (psi(g) and psi(o)) to the current design rules of CIDECT (2008) for carbon steel CHS tubular K-joints, considering the effects of key geometric parameters of beta, tau, 2 gamma and O-v, respectively. The proposed design rules can accurately predict the bearing capacity of stainless steel hybrid tubular K-joints with square braces and circular chord, being only 1% conservative to the FE strengths. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This paper presents a finite-element investigation on the bearing capacity of stainless steel hybrid tubular K-joints. The parametric study results showed that joint strengths are influenced by specific geometric parameters. The proposed design rules can accurately predict the bearing capacity of joints and are only 1% conservative to the FE strengths.