Static and seismic cyclic behavior of SHS-to-CHS and H-to-CHS X-joints

Document Type

Article

Publication Date

9-1-2026

Abstract

This paper studies the structural behavior of welded X-joints composed of square hollow section (SHS) braces connected to circular hollow section (CHS) chords (SHS-to-CHS) and those consisting of H-section braces to CHS chords (H-to-CHS). Here, the H-section braces are arranged transversally and longitudinally, i.e., the web of the H-section are perpendicular and parallel to the chord axis, respectively. Experimental and numerical studies are conducted to reveal the performance of these two types of X-joints under static and cyclic brace axial loading. It is found that the specimens under static loading fail due to plastic softening of the chord wall. The specimens under cyclic loading fail due to tearing of the chord wall after plastic development, but the post-tearing crack propagation paths vary across different joint types. The compressive strength of the X-joints under static loading approximates that under cyclic loading, yet the deformability and ductility ratio under static loading are larger. SHS-to-CHS X-joints and transversal H-to-CHS X-joints exhibit close strength and energy dissipation capacity, which are larger than those of longitudinal H-to-CHS X-joints. Reducing the chord radius-to-thickness ratio can improve the strength and ductility ratio of the SHS-to-CHS X-joints at the cost of energy dissipation capacity. The brace-chord angle (θ), when it is smaller than 90°, helps enhance the strength of the X-joints. The X-joints exhibit higher tensile strength than compressive strength. An equation for predicting the tension-to-compression strength ratio is developed and validated by experimental results and eighty-three finite element strength data.

Publication Source (Journal or Book title)

Thin Walled Structures

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