Quasi‐Newton Method for Reinforced‐Concrete Column Analysis and Design

A practical method for the analysis and design of reinforced‐concrete columns under uniaxial/biaxial loads is presented. In this iterative method, the section strength is evaluated based on a known neutral axis and/or assumed steel ratio. Variation of the neutral axis parameters and steel ratio, as well as central difference method, made it possible for the calculation of the partial derivatives required in the multivariable nonlinear Newton's method. The solution scheme is suitable for computer application. Several examples, including analysis and design of columns under uniaxial tendings, biaxial tendings, or sections of unusual shapes, are also presented in this paper. In all the cases, starting from an arbitrarily given neutral axis position and steel ratio, convergence is attained in only severe iterations.