Square Hollow Section (SHS) Weight Calculation Guide

"Structural efficiency meets mathematical precision. Square Hollow Sections (SHS) are the preferred choice for modern architectural frames, but their weight estimation requires more than just a simple scale."

Square Hollow Sections (SHS) provide an exceptional strength-to-weight ratio, making them indispensable in industrial sheds, automotive chassis, and decorative architectural elements. Unlike solid bars, the "hollow" nature of these sections means that their weight is strictly a function of the perimeter and wall thickness.

The Calculation Process

To calculate the weight of an SHS, we determine the cross-sectional area by subtracting the inner square's area from the outer square's area, then multiplying by length and steel density.

Step-by-Step Logic

1. Outer Area = Width²

2. Inner Width = Width - (2 × Wall Thickness)

3. Inner Area = Inner Width²

4. Steel Area = Outer Area - Inner Area

5. Weight = Steel Area × Length × 0.00000785

Common SHS Weight Reference

Size (mm)	Thickness (mm)	Weight per Meter (kg/m)
25 x 25	2.0	1.44
50 x 50	3.0	4.43
100 x 100	4.0	11.70
150 x 150	5.0	22.20

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Manufacturing Tolerances and Corner Radii

It's important to note that most industrial SHS profiles are cold-formed, which means they have slightly rounded corners. This "corner radius" can reduce the total steel volume by 0.5% to 1% compared to a perfectly sharp-edged theoretical model.

Frequently Asked Questions

What is the formula for SHS weight calculation?

Weight = (Outer Area - Inner Area) × Length × Density. Simply: [OD² - (OD - 2×Thickness)²] × 0.00785 for weight in kg/meter (where dimensions are in mm).

Do rounded corners affect SHS weight?

Yes, cold-formed SHS has rounded corners which marginally reduce the total steel volume. Theoretical calculations based on sharp corners will overestimate weight by about 0.5% to 1.5% compared to the actual scale weight.

Is SHS lighter than solid square bar?

Significantly lighter. A 50x50x3mm SHS weighs ~4.5 kg/m, whereas a solid 50x50mm square bar weighs ~19.6 kg/m. This 75%+ weight saving is why hollow sections are preferred for structural frames.

Can I use this formula for RHS (Rectangular Hollow Sections)?

The logic is identical, but the area formula changes. For RHS, Outer Area = Width × Height, and Inner Area = (Width - 2t) × (Height - 2t).

What is strict tolerance for SHS wall thickness?

IS 4923 allows a thickness tolerance of ±10%. A '4mm' thick tube could physically be 3.6mm to 4.4mm, directly impacting the actual weight per meter.

Summary

By mastering the subtraction method for hollow sections, engineers can ensure that their structural frame weight estimates are conservative, safe, and accurate for procurement.

Ayask Steel delivers high-strength structural components for heavy engineering projects. Our deep understanding of material properties ensures that your projects are built on a foundation of precision.