Non-linear analysis of continuous composite beams by a mixed approach

A three fields mixed finite element is proposed for the non-linear analysis of composite beams with weak shear connection. The formulation is based on the Hu-Washizu functional and considers the non-linear behaviour of materials and deformable shear connectors. Numerical applications are performed using as working example a steel-concrete two span continuous beam that is of practical interest in structural engineering and a difficult test for composite beam elements. The results are discussed and comparisons are made between the established mixed element and displacement based elements adopted by the authors in previous works.