Hollow Structural Steel Weight Calculator
Accurately calculate the weight of hollow structural sections (HSS), including square, rectangular, and round steel tubing.
Figure 1: Comparison of HSS Weight vs. Solid Bar Weight (Efficiency Check)
Calculation Breakdown
| Parameter | Value |
|---|
What is a Hollow Structural Steel Weight Calculator?
A hollow structural steel weight calculator is an essential engineering tool designed to compute the theoretical mass of Hollow Structural Sections (HSS). These sections are metal profiles with a hollow tubular cross-section, widely used in welded steel frames, columns, and architectural structures.
Engineers, fabricators, and procurement managers use this tool to estimate material requirements, shipping costs, and structural loads. Unlike solid steel bars, HSS profiles (Square, Rectangular, and Round) offer a high strength-to-weight ratio. Accurately calculating their weight is critical for ensuring that cranes, trucks, and foundations are not overloaded.
Common misconceptions include assuming all steel has the same density or neglecting the corner radius in precise calculations. While this calculator uses nominal dimensions for standard estimation, it provides a highly accurate baseline for budgeting and logistical planning.
Hollow Structural Steel Weight Calculator Formula
The core principle behind the calculation is simple physics: Mass = Volume × Density. However, determining the volume of the material requires subtracting the inner void from the outer shape.
The General Formula
$$ \text{Weight} = (\text{Area}_{\text{outer}} – \text{Area}_{\text{inner}}) \times \text{Length} \times \text{Density} $$
Depending on the shape, the cross-sectional area calculation differs:
- Square/Rectangular (SHS/RHS):
Area = $(W \times H) – ((W – 2t) \times (H – 2t))$ - Circular (CHS):
Area = $\pi \times (R_{outer}^2 – R_{inner}^2)$
Variables Table
| Variable | Meaning | Metric Unit | Imperial Unit |
|---|---|---|---|
| W / H | Width / Height | mm | inches |
| t | Wall Thickness | mm | inches |
| L | Length | meters | feet |
| ρ (Rho) | Density | 7850 kg/m³ | 0.2836 lb/in³ |
Practical Examples
Example 1: Warehouse Column (Square HSS)
A structural engineer needs to order 10 columns for a warehouse.
Specs: 100mm x 100mm square tube, 5mm wall thickness, 6 meters long.
- Area Calculation: Outer Area = 10,000 mm²; Inner Area = (90×90) = 8,100 mm². Net Area = 1,900 mm².
- Volume per Piece: 1,900 mm² × 6,000 mm = 11,400,000 mm³ = 0.0114 m³.
- Weight per Piece: 0.0114 m³ × 7850 kg/m³ ≈ 89.49 kg.
- Total Order Weight: 894.9 kg.
Example 2: Handrail Pickets (Round HSS)
A fabricator is building a fence using 50 pieces of round tubing.
Specs: 2 inch outer diameter, 0.125 inch wall thickness, 8 feet long.
- Weight per Foot: Approx 2.5 lb/ft.
- Total Footage: 50 pieces × 8 ft = 400 ft.
- Total Weight: 400 ft × 2.5 lb/ft = 1,000 lbs.
How to Use This Hollow Structural Steel Weight Calculator
- Select System: Choose between Metric (mm/kg) or Imperial (in/lb) based on your blueprints.
- Choose Shape: Select Square (SHS), Rectangular (RHS), or Round (CHS).
- Enter Dimensions: Input the outer width/height or diameter. Input the wall thickness carefully.
- Set Length & Quantity: Enter the length of a single bar and the total number of bars required.
- Review Material: Default is Carbon Steel. Change to Aluminum or Stainless if needed.
- Analyze Results: Use the "Copy Results" button to paste the data into your quote or bill of materials.
Key Factors That Affect HSS Weight
When using a hollow structural steel weight calculator, consider these real-world factors that influence the final logistical weight:
1. Material Density Variations
While standard steel is often calculated at 7850 kg/m³, different alloys vary. Stainless steel is slightly heavier (~7900 kg/m³), while aluminum is significantly lighter (~2700 kg/m³). Using the wrong density can lead to a 60% error in weight estimation.
2. Corner Radius (Geometric Tolerance)
In reality, square and rectangular tubes do not have sharp 90-degree corners; they are rounded. This removes a small amount of material mass. Simple calculators (like the nominal method) may slightly overestimate weight compared to the exact "radius-adjusted" theoretical weight, usually by 1-3%.
3. Galvanizing and Coatings
If the steel is hot-dip galvanized, the zinc coating adds roughly 3-5% to the total weight. Paint and primer add negligible weight for transport but should be considered for surface area calculations.
4. Manufacturing Tolerances
ASTM and EN standards allow for wall thickness tolerances (often -5% to +10%). A "nominal" 5mm thickness might actually be 4.75mm or 5.25mm, affecting the actual scale weight of the bundle.
5. Cost Implications
Steel is often sold by weight. A slight miscalculation in the hollow structural steel weight calculator can translate to budget discrepancies. Always add a contingency buffer (e.g., 5%) for scrap and variance.
6. Scrap and Cutting Kerf
If you are cutting 6m bars into 1m pieces, you lose material to the saw blade (kerf). While this doesn't change the weight of the raw bar, it changes the "effective" weight of the finished product.
Frequently Asked Questions (FAQ)
No, this calculator uses the nominal dimension method (subtracting inner box from outer box). This is the standard method for rapid estimation. For precise engineering loads requiring corner radius subtraction, consult the specific manufacturer's data sheet.
The wall thickness cannot exceed half of the outer dimension (or radius for round tubes), as this would mean the hole is non-existent or the geometry is impossible (negative volume).
The standard density used for mild carbon steel is 7850 kg/m³ in metric or 0.2833 lb/in³ in imperial units.
Yes. Select "Aluminum" from the Material Density dropdown. Aluminum is approximately one-third the weight of steel.
SHS is Square Hollow Section, RHS is Rectangular Hollow Section, and CHS is Circular Hollow Section. They are all forms of HSS (Hollow Structural Sections).
Multiply the kg/m value by 0.6719 to get lb/ft. Conversely, divide lb/ft by 0.6719 to get kg/m.
No. "Weight per meter" is a property of the cross-section (width, height, thickness). Total weight increases linearly with length.
Yes, significantly. HSS provides structural efficiency by placing material where it handles bending stress best (the perimeter), leaving the center void to save weight.
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- Metal Weight Converter – Convert between different metals and shapes.
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