Capacity Difference of Circular Hollow Section X-joints Under Brace Axial Compression and Tension

Autor: Yangzheng Cai, Bida Zhao, Zeyang Yao, Chengqing Liu
Rok vydání: 2020
Předmět:
Zdroj: International Journal of Steel Structures. 20:1443-1453
ISSN: 2093-6311
1598-2351
DOI: 10.1007/s13296-020-00374-w
Popis: In the current regulations, there are two methods to describe the relationship between the two capacities of circular hollow section (CHS) X-joints under brace compression (Nuc) and brace tension (Nut): Nut = Nuc and Nut = fNuc (f is a coefficient larger than 1.0). In order to study the difference between Nuc and Nut of the X-joints, two experimental tests (monotonic compression load and cyclic axial load) and finite element (FE) analysis are performed to study the difference between Nuc and Nut. Test results show that the ultimate capacity is close to the resistance load corresponding to the connection deformation of 3% of chord diameter (limit deformation criterion). Both two specimens showed good deformability and ductility. The final failure modes are chord wall buckling and chord wall tearing for the specimens under monotonic compression load and cyclic axial load, respectively. Test and FE results indicate that Nut is significantly larger than the corresponding Nuc, and the ratio Nut/Nuc increases as the chord radius-to-thickness ratio γ increases. It is also found that the ratio Nut/Nuc increases as the brace-to-chord diameter ratio β increases, especially β larger than 0.8. Based on test and FE data, a new equation for the ratio Nut/Nuc is proposed to overcome the defect of the current specifications that cannot consider the influence of β. The equation is proved to be reasonable by tests and FE results.
Databáze: OpenAIRE
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