The use of square cross sections of unit-length side for the analysis of rectangular solid and hollow sections under biaxially eccentric loads

Abstract

This paper deals with the analytical proof of the equivalence between the relative design axial load and biaxial bending resistance of a solid and hollow rectangular section, and the design axial load and biaxial bending resistance of the associated square solid and hollow cross sections of unit-length side. The results of the proof showed that the equivalence exists only if the design compressive strength of the concrete in the square cross section of unit-length side is equal to one for solid sections and 1/α for hollow rectangular sections, where α is defined as the ratio of the solid to the gross cross sectional area. The new sets of compressive strengths and transformations of rectangular sections into square cross section of unit-length side have been shown to be matched with consistent transformations of the design yield strength of reinforcing bars, locations of concrete fibre and rebar, and area of reinforcement.

Keywords: Biaxial eccentric load, Hollow section, Solid sections, Square cross section.