Nonlinear analysis of RC shell structures using laminated element. II

Abstract

An incremental variational formulation and curved-shell element were proposed in the companion paper. In this part, the material model and solution techniques are discussed in detail. The strain-hardening plastic approach is employed to model the compressive behavior of the concrete. A dual criterion is considered for yielding and crushing in terms of stresses and strains, which is completed with a tension cut-off representation. Both the crack interface effects and dowel action are accounted for using an average shear modulus, and a full bond is assumed at the steel-concrete interface. A total Lagrangian approach making use of the second Piola-Kirchhoff stress tensor is employed in this analysis. An incremental and iterative modified Newton-Raphson scheme is used for the solution of nonlinear problem. An energy criterion in terms of both forces and displacements is implemented,. The applicability and validity of this analytical model incorporating both geometrical and material nonlinearities is amply demonstrated through several numerical examples. The solution technique proposed in this paper has been shown to be successful in preventing the drifting of the solution in incremental process.