Numerical formulation for nonlinear analysis of concrete and steel shells with deformable connections

Abstract A two-dimensional interface finite element capable of associating flat shell elements positioned one above the other was developed. The implemented interface element can physically simulate the contact between the flat shell elements and connect the reference planes of the shell elements above and below it. The formulation presented allows consideration of nonlinear behavior for the deformable connection as well as for the concrete and steel materials that make up the shell structure. One of the practical applications analyzed in this research is the numerical simulation of composite floors formed by a reinforced concrete slab connected to steel beams through a deformable connection. In this case, the concrete slab and the steel beams are discretized by flat shell elements and the deformable connection is discretized by two-dimensional interface elements. Experimental and numerical results from literature were used to validate the implemented elements. In the two examples analyzed, the results obtained for the displacements were close, with the difference, in the first case, being associated with uncertainties during the experimental test and in the second, the difference in theories used in the formulation of the implemented elements.