Proposed Mathematical Model for Semi-Rigid Joint Behaviour (M-θ) in Space Structures

In the present paper, an exponential mathematical model for prediction of moment-rotation behaviour of semi-rigid connections in space structures is proposed. This model has two parameters in relation to mechanical properties of the semi-rigid connection. The parameters include the ultimate moment capacity of the connection and the initial stiffness of the connection corresponding to flexural deformation. An analytical method is proposed to find the ultimate moment capacity. Also, initial stiffness could be found from analytical or simple experimental test. The validity of the proposed model has been verified using a number of experimental results. The results indicate that the proposed model has good capability to simulate the behaviour of joints where exhibit elastic-plastic hardening characteristics with the curve flattening out near the final stage of loading.