NONLINEAR-ANALYSIS OF RC SHELL STRUCTURES USING LAMINATED ELEMENT .2.

An incremental variational formulation and a 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 pla stic approach is employed to model the compressive behavior of the con crete. A dual criterion is considered for yielding and crushing in ter ms of stresses and strains, which is completed with a tension cut-off representation. Both the crack interface effects and dowel action are accounted for by using an average shear modulus, and a full bond is as sumed at the steel-concrete interface. A total Lagrangian approach mak ing use of the second Piola-Kirchhoff stress tensor is employed in thi s analysis. An incremental and iterative modified Newton-Raphson schem e is used for the solution of nonlinear problem. An energy criterion i n terms of both forces and displacements is implemented. The applicabi lity and validity of this analytical model incorporating both geometri cal 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.