Capacity of axially loaded RC columns with arbitrary cross sections to Eurocode 2

Abstract

Unlike older design codes, Eurocode 2 does not provide a procedure for calculation of the capacity of axially loaded columns. For that purpose, a general algorithm is developed, using the principles of structural mechanics and mathematics: It starts with constructing the P-Δ relationship (buckling curve) for the element, accounting for initial imperfections, minimum eccentricity, material nonlinearity and second order effects. Then, the respective bending moments are determined from the displacements and the P-M relationship is obtained. Finally, the axial load capacity in planar domain is determined by intersecting the P-M diagram with the interaction curve for the RC section. In spacial domain, the P-Δ relationship is defined by the respective “buckling surface”. Its intersection with the interaction surface represents a spacial curve in the (P, Mx, My) coordinate system. The axial capacity is determined as the minimum of P values along the curve. The solution is performed by numerical methods.