Analytical investigation on effective elastic stiffness of eccentric steel beam–column joints

Eccentric steel beam–column joints could satisfy the architecture requirements flexibly. They were occasionally used in buildings such as the Huarun Group Headquarters Building (400？m) in Shenzhen, China. However, the eccentricity decreases the mechanical properties including the elastic stiffness significantly. This article focused on the analysis of the effective elastic stiffness of eccentric steel beam–column joints. First, an analytical model was proposed to calculate the effective elastic stiffness. In the model, the deformation of the joint core was divided into six components: three shear deformations and three torsion deformations. Moreover, the accuracy of the model was verified by comparison with the finite element results. A parametric analysis was performed and the critical factors influencing the elastic stiffness were obtained. Finally, the analysis of the eccentric and concentric frame systems was conducted. The periods of natural vibration, lateral displacements, story drifts and story shear forces obtained were different in the two kinds of frames, which indicated that eccentricity contribution should be carefully considered for a rational design of eccentric joints