Comparative analysis on ultimate capacity of partially overlapped SHS K-and KK-joints

In order to obtain the relationship of the load-carrying capacity between partially overlapped SHS (square hollow section) K-joints and their corresponding KK-joints, and establish the reasonable method to calculate the capacity of overlapped SHS KK-joints finite element analyses of 93 pairs of partially overlapped SHS K-joints and KK-joints were conducted using ANSYS software involving large deformation elastic-plastic range. The plastic developing process and failure mode of the joint were studied, and the static behavior of the joint under two loading ways was compared. The laws of the ultimate capacity ratio of K-joints and KK-joints (namely multiplanar coefficient) varying with the main geometrical parameters were obtained. Multiplanar coefficient equation of partially overlapped SHS K-joints and KK-joints relating directly to the geometric parameters was developed from the multiple regression analysis. The equation was found to provide ultimate capacity ratio predictions to a high degree of accuracy by comparing its results with the results of finite element analysis in this paper. So, the strength of KK-joint can be obtained from the strength of K-joint with corresponding parameters by multiplying the multiplanar coefficient.