Author(s)

C. G. Chiorean

Abstract

A new computer method for bi-axial ultimate strength analysis of composite steel-concrete cross-sections of arbitrary shape subjected to axial force and biaxial bending moments is developed. An incremental-iterative procedure based on arc-length approach is proposed in order to determine, in a unitary formulation, both interaction diagrams and moment capacity contours, overcoming the difficulties and inaccuracies of the previously published methods. This procedure adopts a tangent stiffness strategy for the solution of the non-linear equilibrium equations thus resulting in a high rate and unconditionally convergence. An object oriented computer program, to obtain the ultimate strength of composite cross-sections under combined biaxial bending and axial load was developed. Examples run and comparisons made have proved the effectiveness and time saving of the proposed method of analysis. Keywords: composite cross-sections, ultimate strength, arc-length method, bi-axial bending. 1 Introduction In recent years, some methods have been presented for the ultimate strength analysis of various concrete and composite steel-concrete sections such as rectangular, L and T -shape, polygonal and circular under biaxial moments and axial loads [1–5]. Among several existing techniques, two are the most common; the first consists of a direct generation of points of the failure surface by varying the position and inclination of the neutral axis and imposing a strain distribution corresponding to a failure condition. This technique generates the failure surface

Keywords

composite cross-sections, ultimate strength, arc-length method, bi-axial bending