PRACTICAL NONLINEAR INELASTIC ANALYSIS METHOD OF 3D COMPOSITE STEEL-CONCRETE FRAMEWORKS
Stefan M. Buru 1 and Cosmin G. Chiorean 1*
1 Department of Structural Mechanics, Technical University of Cluj-Napoca, Romania
A second-order flexibility based model has been developed for advanced analysis of 3D composite steel-concrete frameworks with partial composite action. Both distributed plasticity and element geometrical effects are modeled by combining the Maxwell-Mohr rule and the second-order force based functions for the derivation of the force-displacement relationship at the element level. The proposed model allows efficient modeling of the combined effects of nonlinear geometrical effects, spread-of-plasticity, partial shear connection of composite beams, finite-size joints and joint flexibility by using only one 2-noded beam-column element per physical member. The proposed nonlinear inelastic analysis formulation has been implemented in a general nonlinear static purpose computer program, NEFCAD. An advanced FEM model has been developed in Abaqus software considering a combination of three-dimensional solid elements (for concrete volumes) and shell elements for steel elements allowing also the partial composite action between the steel beam and concrete slab. Several computational examples are given to validate the accuracy and reliability of the proposed method.
Nonlinear inelastic analysis; Flexibility-based element; Distributed plasticity; Partial composite action; Advanced analysis