Chord-end RHS-to-RHS and CHS-to-CHS X-connections with rigid cap plates: Stress concentration factors

• Published in: Journal of constructional steel research Vol. 179; p. 106567
• Main Authors: Sun, Min, Tousignant, Kyle, Ziaei Nejad, Ali, Daneshvar, Sara
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2021
• Subjects: Cap plates; Circular hollow sections; End effects; Fatigue design; Rectangular hollow sections; Stress concentration factors; X-connections; Stress concentration factors; Fatigue design; Rectangular hollow sections; End effects; Circular hollow sections; Cap plates; X-connections
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2021.106567

For rectangular hollow section (RHS)-to-RHS and circular hollow section (CHS)-to-CHS connections situated near a truss/girder end, reinforcement using a chord-end cap plate is common; however, for fatigue design, formulae in current design guidelines [for calculation of stress concentration factors (SCFs)] cater to: (i) unreinforced connections, with (ii) sufficient chord continuity beyond the connection on both sides. To develop definitive design guidelines for end connections with rigid cap plates, previous full-scale connection test results have been used to validate a finite element (FE) modelling approach, and a total of 496 FE models with different chord end distance-to-width (or diameter) (e/b0 or e/d0), branch-to-chord width (β), branch-to-chord thickness (τ), and chord slenderness (2γ) ratios have been modelled and analyzed. Existing SCF formulae in CIDECT Design Guide 8 are shown to be inaccurate if applied to cap plate-reinforced end connections. SCF correction factors (ψ), and parametric formulae to estimate ψ based on e/b0 (or e/d0), β, τ and 2γ, are derived.
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•SCFs of chord-end RHS-to-RHS and CHS-to-CHS X-connections with rigid cap plates are studied.•496 FE models are analyzed.•CIDECT DG8 SCF formulae are found to be inaccurate.•A new approach for predicting SCFs in “end connections with rigid cap plates” is proposed.•The approach utilizes “SCF correction coefficients” plus CIDECT DG8 formulae.