Abstract This paper presents a general formulation for the analysis of steel hollow structural beams subjected to biaxial bending. The model has been developed within the framework of lumped damage mechanics. In this approach, the models are based on methods of continuum damage mechanics and the concept of plastic hinge. The model was implemented in a commercial finite element program. In order to calibrate the model, a set of experimental tests were carried out in the Structural Mechanics Laboratory at the Lisandro Alvarado University. The model was evaluated by the numerical simulation of these tests finding a good agreement between the experimental tests and the numerical simulations.