Theoretical modeling of semirigid connections behavior

Abstract The semirigid, and nonlinear, behavior of the connections in civil engineering structures is now well recognized. Nevertheless, it is accepted and codified in the steel structures only. Therefore, it is necessary to have mathematical models in order to allow exact frame analysis with computer programs. The proposed model of this paper is based on physical parameters and verifies, a priori , the thermodynamics principles. The energy dissipation, associated with the nonlinearity, is considered as the main phenomenon. The model is established in the unidimensional case—moment and rotation—which is the most usual and the most interesting in view of the cheaper design. The extension to the more general case (six degrees of freedom) is introduced with the same concepts. The predictable feature of this model is emphasized in comparison with other curve-fitting techniques.