 # D13.D.4 Columns

Reinforcement for columns of rectangular or circular cross section can be calculated. The flexibility of columns can be evaluated in two ways.

• In the case of linear analysis (i.e., the PERFORM ANALYSIS command), the effective length is evaluated using the ELY and ELZ parameters, conforming to provisions of SP5 2.13330.2011.
• If a P-DELTA or NONLINEAR (i.e. nonlinear geometry) analysis is performed, the values of the ELY and ELZ parameters should be close to zero (e.g., ELY = ELZ = 0.01).

Longitudinal reinforcement for columns is calculated only for the strength condition. Longitudinal forces and bending moments in relation to local axes Y and Z are taken into account in longitudinal reinforcement calculations.

For rectangular columns, the following output is generated:

• column number;
• column length and cross-sectional dimensions;
• distance of centroid of each longitudinal bar from the nearest edge of the cross-section;
• concrete class;
• longitudinal reinforcement class;
• range of longitudinal reinforcement bar diameters assumed in calculation;
• diameter of longitudinal reinforcement bars obtained in calculation;
• total quantity of longitudinal bars;
• quantity of longitudinal bars at each cross-section edge, directed parallel to the local axis Y ;
• quantity of longitudinal bars at each cross-section edge, directed parallel to the local axis Z.

In nine columns of the table under the heading LONGITUDINAL REINFORCEMENT, the following output is presented:

• Section – distance of the section from the start of the column, mm;
• Astot – total cross-sectional area of longitudinal reinforcement, sq.cm;
• Asy – cross-sectional area of longitudinal reinforcement bars at each edge of section, directed parallel to the local axis Y , sq.cm;
• Asz – cross-sectional area of longitudinal reinforcement bars at each edge of section, directed parallel to the local axis Z , sq.cm;
• Percent – reinforcement percentage in the section;
• Nx, Mz, My – respective values of longitudinal force and bending moments in relation to the local axes Z and Y , determining cross-sectional area of longitudinal reinforcement;