Design Principles
Columns are designed for axial force and bi-axial end moments, as well as bi-axial shear. Torsional moments are not considered. Reinforcement is designed by the program based on the forces generated in the Concrete Analysis module and the force adjustment procedure given in the code and outlined below:
- Adjust M, V, N for seismic effects for Transfer Columns (ONLY seismic load cases)
- For seismic combinations, adjustment/calculate Mtop and Mbtm based on frame type, member type, earthquake intensity parameter and other relevant parameters.
- From Mtop and Mbtm calculate the end shears in the column.
- For axial loads, use analysis results multiplied by adjustment factor specified in code.
- For non-seismic combinations, calculate combinations from analysis results as normal, and do not perform any adjustment.
Load Capacity Ratio
For each column and for each load combination (and skip pattern if live load) the program calculates a single load capacity ratio. This capacity ratio is based on the largest of the design moments divided by the moment capacity of the cross section (which includes the effect of axial load on the section).