Constitutive model for rotation behaviour of semi-rigid steel beam-to-column joints

Abstract

This study proposed a generalised and concise model consisting of spring-slider elements to characterise the nonlinear bending moment-rotation relationship of semi-rigid steel beam-to-column joints. First, the density function of the constitutive model was constructed based on the rotational characteristics of the joints. Second, the mathematical expression for the moment-rotation relationship of the constitutive model was derived. A method was developed to identify the parameters. Finally, after a discretisation method of the model was derived based on the strategy of evenly divided stiffness, the discrete model was applied to the numerical simulation of the rotation of the semi-rigid steel beam-to-column joints. It is observed that the proposed model accurately describes the rotation behaviour of semi-rigid connections in the entire rotation domain while reducing the degrees of freedom of the contact interfaces to improve the computing efficiency. There are six parameters in the model with a clear physical definition, which can be directly identified through macroscopic experiments. A high level of accuracy can be achieved by numerically calculating a discrete model using only five Jenkins elements.