Effects of Out-of-plane Brace-to-chord Angle on Multiplane CHS X-joints Behavior Under Brace Compression

  • Bida Zhao Zhejiang University of Technology
  • Ke Li Zhejiang University of Technology
  • Chengqing Liu Southwest Jiaotong University
  • Dengjia Fang Southwest Jiaotong University
  • Jianguo Wu Zhejiang University of Technology


Multiplanar CHS X-joints, different from the common uniplanar CHS X-joints, usually with a relative small out-of-plane brace-to-chord angle (OPBCA) for appealing architectural appearance in the single layered lattice structures. In order to study the effects of OPBCA on the static behavior of circular hollow section (CHS) X-joints under brace axial compression, experimental tests and numerical parametric study on the ultimate capacity and load transfer pattern of the CHS X-joints were carried out. The numerical analysis results had good consistent with experimental tests in terms of the capacity and fail mode of the X- joints. OPBCA changes the load transfer pattern to more load at the up saddle point from the same load at the up and bottom saddles in uniplanar X-joints, and more obvious for the X-joints with lager OPBCA. OPBCA is also unfavorable to the capacity, especially the X-joints with relative large brace-to-chord diameter ratio and in-plane brace-to-chord angle. Then an equation considering the OPBCA influence factor, extended the capacity prediction formulae of uniplanar X-joints in the current specifications to the multiplanar X-joints, is also established; and the equation has been validated favorably.

Keywords: CHS X-joints, out-of-plane brace-to-chord angle (OPBCA), load transfer pattern, ultimate capacity, OPBCA influence factor
Published online
How to Cite
Zhao, B., Li, K., Liu, C., Fang, D., & Wu, J. Effects of Out-of-plane Brace-to-chord Angle on Multiplane CHS X-joints Behavior Under Brace Compression. Periodica Polytechnica Civil Engineering. https://doi.org/10.3311/PPci.13738
Research Article