Direct Design Method and Design Diagram for Reinforced Concrete Columns and Shear Walls

Abstract

Design of reinforced concrete columns and shear walls is an iterative process. Whether done manually or computer aided, the capacity of an assumed section is checked using interaction diagrams and the procedure continues until a satisfactory section is found. This research introduces two new concepts for design of reinforced concrete columns, “Direct Design” method and “Design Diagram”. Direct design method is an analytical approach by which the required area of reinforcement is determined directly without using an interaction diagram. In this approach, location of the neutral axis and required area of reinforcement is found directly by solving a non-linear system of equations. Direct design method provides an optimum solution for a reinforced concrete section; the capacity of the section is exactly equal to the applied load and moments. For each column or shear wall, there are many optimum sections with different sizes and bar arrangements. A design diagram shows all possible optimum sections for a column or shear wall. This study provides an algorithm and a computer program for making design diagrams. Having a design diagram, designers do not need to go through a trial-and-error procedure to find an acceptable section; they can simply pick up an optimum section that best fits their requirements from the design diagram.