Design any concrete or composite column. Draw the section — standard shapes, your own polygon with holes, bars placed by generators or dragged one by one, encased steel sections or filled tubes — and get the full P–Mx–My interaction surface by strain compatibility to AS 3600, ACI 318, AASHTO LRFD, BNBC 2020 or Eurocode 2. Check every load case by its capacity ratio, magnify slender columns, trace moment–curvature with confined concrete, read the stresses in every fibre, and detail the ties, spirals and confinement — with drawings, a 3D surface, calculation sheets, Excel and a priced bill of quantities.
Scope & limitations
Preliminary design tool. Interaction surfaces use each code's stress block and capacity factors with plane sections and perfect bond; confirm detailing, seismic provisions and second-order effects in frames against the full code and your analysis model.
What the Column Studio does
Build any column section in the section designer: rectangle, circle, hollow rectangle and circle, L, T, I, cross, regular polygon, or a polygon of your own with holes — with reinforcing bars placed by perimeter, circular or layer generators or one by one, and dragged on the drawing. Encased steel I-sections and concrete-filled steel tubes (rectangular and circular) make composite columns.
The section is cut into fibres and the full biaxial P–Mx–My interaction surface is built by strain compatibility for every neutral-axis angle with the code's stress block, ultimate strain and capacity factor: AS 3600-2018, ACI 318-19, AASHTO LRFD, BNBC 2020 and Eurocode 2 (BS EN 1992-1-1 with the UK National Annex, parabola–rectangle and the pivot rule). The studio draws P–M diagrams at any angle, Mx–My contours at any axial load and the 3D surface, and reports the capacity ratio of every load case along the ray from the origin, the moment ratio at constant axial load and the simplified biaxial checks (Bresler, AS 3600 αn, Eurocode exponent).
Slender columns are magnified by the code method (ACI and AASHTO moment magnifier with EIeff, AS 3600 δb and δs, Eurocode 2 nominal curvature with the l0/400 imperfection, BNBC as ACI), with minimum eccentricity. Moment–curvature uses Mander confined concrete for the core and unconfined cover with strain-hardening steel to give cracking, first yield and ultimate moments, curvature ductility and the effective stiffness.
Section properties (gross and transformed, principal axes, plastic centroid), the stress and strain in every fibre for a chosen load, steel ratio, bar spacing, tie and spiral rules, confinement and column shear complete the design. Output: section and elevation drawings with a tie schedule, interaction diagrams, a 3D surface and column model, PDF calculation sheets, an A3 drawing set, Excel and CSV of the surface, and the cost and bill of quantities for the columns.