Analytical integration of cross section properties for numerical analysis of reinforced concrete, steel and composite frames

This paper presents a procedure for numerical analysis of steel, reinforced concrete or composite cross section of arbitrary polygonal shape, based on analytical evaluation of cross section properties, i.e., section resistant forces and tangent moduli. The uniaxial stress–strain relationship is supposed to be of a piecewise polynomial type, and the subdivision of the section into subregions is performed by means of a contouring algorithm. The procedure may be easily implemented into a beam–column finite element code which works with evaluation of cross section properties at the numerical integration points.