Circular & annular column
TCVN 5574:2018Check provided steel or design total As,tot for circular/annular columns under one-axis N + M per TCVN 5574:2018 Appendix F.
About the circular spiral column tool
Check or design reinforcement for a circular column with helical (spiral) confinement in uniaxial eccentric compression (N + M) per Annex F TCVN 5574:2018.
What you enter
Column diameter, cover, concrete/steel grades, spiral parameters (bar diameter, pitch) and the (N, M) force combination.
What the results mean
Section capacity from the Annex F formulas; design mode returns the required longitudinal bar area and total As,tot.
When to use this tool
Corridor columns, staircase drum columns and architecturally round columns — the typical spots where spiral-confined circular sections appear.
Calculation method
This tool checks or designs reinforcement for circular columns with spiral/annular ties under one-axis eccentric compression (N + M) per TCVN 5574:2018 Appendix F.
Enter the column diameter, cover, materials and force combination; the tool applies the Appendix F formulas and concludes on the load-bearing capacity, or proposes the required longitudinal/total As,tot when in design mode.