Cross-section database

How it calculates

The Cross-Section Database calculator is a lookup and property-derivation tool rather than a design calculator. It reads from three US section databases, derives geometric section properties using analytical formulae, and makes those properties available to downstream design calculations.

Section databases

Three databases are available depending on the material:

Wood (timber_us) - Standard US sawn lumber and glulam sizes with tabulated species/grade combinations. Section properties are derived from nominal dimensions. The database is aligned with the AWC/ANSI National Design Specification (NDS 2018 or 2024 depending on IBC edition selection) and its Supplement.

Steel (steel_us) - AISC shapes including W, S, M, HP, C, MC, WT, MT, ST, HSS (rectangular), HSS-R (round/pipe), and PIPE profiles. Tabulated values come directly from the AISC Steel Construction Manual - 15th Edition for IBC 2018/2021 and 16th Edition for IBC 2024. Properties such as Ix, Sx, Zx, rx, ry, and Iy are taken directly from AISC tables.

Cold-formed steel (cfs_us) - C, Z, and custom thin-wall sections per the SFIA Technical Guide for Cold-Formed Steel Framing Products (2024 edition). C-sections (studs, tracks, and u-channels), Z-sections, and special sections (flat, slotted, and L-sections) are included with their table-defined geometric properties.

Section geometry derivation

For each material type, the calculator constructs a section geometry object to feed the section properties solver. The geometry representation varies by shape:

• Rectangular (wood): depth d and breadth b in inches
• I-shapes (W, S, M, HP): depth d, flange width b, flange thickness t_f, web thickness t_w, fillet radius r = k_des - t_f
• T-shapes (WT, MT, ST): depth d, flange width b, flange thickness t_f, web thickness t_w, fillet radius r
• C and MC shapes: depth d, flange width b, flange and web thicknesses, root and fillet radii
• HSS rectangular: depth d, width b, wall thickness t, outer corner radius r_out
• HSS round and PIPE: outer diameter d, wall thickness t
• CFS C and Z: depth d, flange width b, lip length l, thickness t, outer corner radius r_out

Section properties calculation

The section geometry is passed to the Calcs.com section properties solver, which computes the following:

• Area (A): total cross-sectional area
• Centroid (y_bar): distance from the reference datum to the elastic neutral axis
• Second moment of area (Ix, Iy): moment of inertia about the major and minor principal axes
• Elastic section moduli (Sx, Sy): I divided by distance to extreme fibre
• Plastic section moduli (Zx, Zy): first moment of area of each half about the plastic neutral axis
• Radii of gyration (rx, ry): rx = sqrt(Ix / A), ry = sqrt(Iy / A)

For standard hot-rolled shapes, section moduli and radii of gyration match AISC tabulated values within rounding.

Material properties

Material strength is assigned from the database record:

• Steel: yield strength Fy from the AISC table for the selected designation (A992 for W-shapes, A36 for angles, or as specified)
• Wood: reference bending design value Fb, modulus of elasticity E, and applicable adjustment factors from the NDS Supplement for the chosen species/grade combination
• Cold-formed steel: base steel yield strength Fy from the SFIA table for the selected section designation

IBC edition and referenced standards

The IBC edition selector governs which material standard edition is cited in the output reference field per IBC Chapter 35:

• IBC 2024: AISC 360-22 (16th Edition Manual), NDS 2024
• IBC 2021: AISC 360-16 (15th Edition Manual), NDS 2018
• IBC 2018: AISC 360-16 (15th Edition Manual), NDS 2018

Selecting the correct edition ensures the reference line in the output matches the code basis of the jurisdiction.

Linking to design calculators

The cross-section database output links to beam, column, and member calculators in Calcs.com. When a design calculator draws EI, section moduli, or strength properties from a linked database calculator, changing the section selection in the database calculator immediately updates every downstream calculation that references those properties.