Cold Formed Steel Section Properties Calculator

Enter Section Data

Section type

Dimension unit

Overall depth

Flange or width

Lip or foot length

Thickness

Inside bend radius

Hole count

Hole diameter

Member length, m

Yield strength, MPa

Density, kg/m³

Example Data Table

Section	Depth	Flange	Lip	Thickness	Yield Strength
Lipped C Channel	150 mm	60 mm	20 mm	2 mm	350 MPa
Lipped Z Section	180 mm	65 mm	18 mm	2.5 mm	450 MPa
Rectangular Hollow Section	100 mm	50 mm	0 mm	3 mm	350 MPa

Formula Used

The calculator uses a rectangular plate component method. Each plate has area A = b × t. Its centroid is found from the plate center. The combined centroid is x̄ = Σ(Ax) / ΣA and ȳ = Σ(Ay) / ΣA.

Second moment of area is calculated with the parallel axis theorem. For each plate, Ix = Ix_local + A(dy²), and Iy = Iy_local + A(dx²). Section modulus is S = I / c. Radius of gyration is r = √(I / A).

Net area is estimated as gross area minus hole count × hole diameter × thickness. Estimated axial yield is P = An × Fy. Estimated elastic yield moment is M = S × Fy.

How To Use This Calculator

Select the cold formed section type.
Choose the dimension unit used by your drawing.
Enter depth, flange width, lip length, thickness, and radius.
Add hole data when a simple net area check is needed.
Enter length, yield strength, and density for weight and capacity results.
Press the calculate button. Results appear above the form.
Use CSV for spreadsheets or PDF for a compact report.

Cold Formed Steel Section Design Notes

Cold formed steel sections are made from thin sheet. The sheet is shaped at room temperature. This gives useful strength with low weight. Designers often need gross section properties before deeper code checks. This calculator supports that first review. It converts basic dimensions into area, centroid, inertia, radius of gyration, section modulus, mass, and simple yield estimates.

Why Section Properties Matter

Area affects axial resistance and weight. Centroid location shows where bending stresses balance. Second moment of area controls flexural stiffness. Section modulus links bending stress to applied moment. Radius of gyration helps with column slenderness checks. These values guide early member sizing and comparison.

Practical Modeling Approach

The tool uses a thin plate model. Each web, flange, lip, or foot is treated as a rectangular plate. The program finds each plate area and local inertia. It then applies the parallel axis theorem. This gives a practical gross property set for common cold formed shapes. It is useful for estimates, takeoffs, teaching, and preliminary checks.

Using The Results Carefully

Cold formed members can buckle locally. Flanges, webs, and lips may become ineffective under compression. Holes, bends, residual stress, fasteners, and connection details also change strength. For that reason, the output should not replace a full design standard. Use it to screen options, compare shapes, and prepare clean calculation records.

Advanced Review Tips

Check the width to thickness ratios after each run. High ratios show thin elements that may need effective width reduction. Review the net area when bolt holes are entered. Compare the strong and weak axis values. A member with good strong axis stiffness may still twist or buckle about the weak axis. Use conservative inputs when dimensions are uncertain.

Report And Export

The export buttons save the current calculation. A CSV file helps spreadsheet comparison. A PDF file gives a simple report for records. Keep the input units, section type, and assumptions with every result. Clear records reduce review time and improve communication between engineers, detailers, and estimators.

When several sections look similar, sort them by mass and modulus. That quick check often finds an efficient member. Still, confirm service loads, bracing, end restraints, corrosion allowance, and fabrication tolerances before final selection.

Frequently Asked Questions

What section types are supported?

The calculator supports lipped C channels, plain C channels, lipped Z sections, hat sections, and rectangular hollow sections. These cover many common cold formed shapes used in light framing, purlins, rails, and small structural members.

Are the results gross or effective properties?

The main output gives gross geometric properties. Effective width reductions are not applied. Use the width to thickness ratios and review note to decide whether a full code based effective section check is needed.

How is net area calculated?

Net area is estimated by subtracting hole count times hole diameter times thickness from the gross area. This is a simple line deduction. Connection design may require more detailed checks.

Can I use inches?

Yes. Select inches in the unit field. The calculator converts dimensions to millimetres internally. Results are reported in metric engineering units for consistent strength and stiffness output.

Does bend radius affect the answer?

The bend radius is included in the developed sheet width estimate. The main inertia calculation uses rectangular plate components. For thick bends or precision production work, verify with a detailed section model.

What does section modulus mean?

Section modulus links bending stress to moment. A larger value usually means better bending strength about that axis. The calculator reports top, bottom, left, and right values.

Why are strong and weak axes different?

Cold formed sections are often unsymmetrical. Material may sit farther from one axis than another. This creates different inertia and modulus values for each bending direction.

Can this replace engineering design?

No. It is a calculation aid for preliminary checks. Final design should follow the relevant steel standard, load combinations, buckling checks, connection rules, and professional judgement.