How to Design a Concrete Column to AS3600:2018The ClearCalcs Concrete Column Calculator allows users to design concrete columns by specifying the desired load cases and dimensions of the column. In this article, each section of the calculator will be explained plus followed by a few worked examples.The Column Calculator has 5 main sections:1. Key Properties.2. Longitudinal Reinforcement.3. Fitment Reinforcement.4. Loads.5. Summary and Graphs.1. Key Properties
You can choose the type of reinforcement for the column shown in the graphic in red, by selecting an option from the drop-down menu.B. Additional Top / Bottom Reinforcement Bars (per side)You can choose how many bars to add to the column to the top and bottom sides of the column, as illustrated in the graphic below in red, by entering the desired number of bars.C. Additional Left / Right Reinforcement Bars (per side)You can choose how many bars to add to the column to the left and right sides of the column, as illustrated in the graphic below in red, by entering the desired number of bars.D. Concrete Cover to FitmentsDistance from concrete surface to ties. While concrete cover must in all cases be at least 20mm, the minimum cover requirement is often greater. See AS 3600:2018 - 2018, Cl 4.10 for specific requirements of minimum cover based upon exposure classification, concrete characteristic strength, and other factors.3. Fitment ReinforcementThe widget helps determine the configuration of fitment (stirrups or ties) reinforcement in concrete columns.
This is the minimum diameter of the fitment reinforcement bars in millimeters (mm). The minimum is typically determined based on structural requirements and code provisions.
L. Special Confinement Region Required Perpendicular to X-axis:
This indicates whether or not a special confinement region (additional reinforcement) is required along the X-axis.M. Special Confinement Region Required Perpendicular to Y-axis:Similarly, this indicates whether a special confinement region is needed along the Y-axis.4. Loads.In order to enter the loads please go to this link here for more information.https://clearcalcs.com/support/get-started-with-clearcalcs/how-to-enter-loads-patch-point-moment-axial5. Summary.In the summary, you can see that a column is safely designed when its demands (axial, shear, and moment) are well within the corresponding capacities, with utilization ratios staying below 100%. High utilization percentages in any area may warrant further analysis or investigation. The summary uses colour-coding to highlight these utilization levels: percentages nearing 100% are shown in yellow as a warning, while values above 100% appear in red, indicating an unsafe condition.Interaction Curve: Moment and Axial Interaction governing in the x and y axis.
The curved line on the graphs, known as the interaction curve or interaction diagram, represents the combined capacity of the column for both axial load and bending moment. Any point on this curve shows the maximum combinations of axial load and moment that the column can sustain without failing.
If the point were on or outside the curve, it would suggest that the columnβs load condition is at or exceeds its safe capacity, which would indicate potential structural risk.