Strength Analysis of Eccentric Rectangular Hollow Section X-Joints Subjected to Axial Compression in the Brace

This paper investigates the mechanics behavior of eccentric rectangular hollow section (ERHS) X-joints subjected to axial compression in the brace, based on which analytical formulas are established to predict the strength of the ERHS X-joints. Static testing is conducted on two ERHS X-joint and one RHS X-joint specimens under brace compression, and the corresponding finite element (FE) analysis is performed. It is found that the ultimate strength of the ERHS X-joints with a medium brace/chord width ratio (beta) is 39% higher than that of the RHS X-joints. The strength and initial stiffness of the ERHS X-joints increase when beta increases. Based on the load transferring mechanism, two analytical models and the corresponding equations are proposed to predict the strength of the ERHS X-joints with beta <= 0.925 and beta=1.0. The proposed models are validated through experimental data and FE results.