Hollow Structural Sections (HSS) are a type of metal profile with a hollow tubular cross-section. They are commonly used in welded steel frames, columns, and as members in trusses. Calculating the weight of HSS accurately is critical for structural engineering, transportation logistics, and project cost estimation.
How is HSS Weight Calculated?
The weight of an HSS member is determined by calculating the cross-sectional area of the metal and multiplying it by the material density and the total length. Since HSS is hollow, we subtract the inner void from the outer dimensions.
For Rectangular/Square HSS:
Formula: Weight = [2t(H + W - 2t)] × Length × Density
Suppose you have a 100mm x 100mm Square HSS with a 5mm wall thickness and a length of 6 meters.
Dimension
Value
Cross Sectional Area
~1,900 mm²
Weight per Meter
~14.92 kg/m
Total Weight (6m)
~89.52 kg
Why use HSS?
HSS offers high strength-to-weight ratios compared to solid sections. Square and rectangular HSS provide excellent resistance to torsion (twisting) and are often preferred for aesthetic reasons in exposed structural steel (AESS). Round HSS is the most efficient section for resisting compression loads in multi-directional buckling scenarios.
function toggleInputs() {
var shape = document.getElementById("hssShape").value;
var dim1Label = document.getElementById("labelDim1");
var dim2Group = document.getElementById("dim2Group");
var units = document.getElementById("hssUnits").value;
if (shape === "round") {
dim1Label.innerHTML = (units === "metric") ? "Outside Diameter (mm)" : "Outside Diameter (in)";
dim2Group.style.display = "none";
} else {
dim1Label.innerHTML = (units === "metric") ? "Height (mm)" : "Height (in)";
dim2Group.style.display = "block";
}
}
function updateLabels() {
var units = document.getElementById("hssUnits").value;
var shape = document.getElementById("hssShape").value;
if (units === "metric") {
document.getElementById("labelDim1").innerHTML = (shape === "round") ? "Outside Diameter (mm)" : "Height (mm)";
document.getElementById("labelDim2").innerHTML = "Width (mm)";
document.getElementById("labelThick").innerHTML = "Wall Thickness (mm)";
document.getElementById("labelLength").innerHTML = "Total Length (m)";
} else {
document.getElementById("labelDim1").innerHTML = (shape === "round") ? "Outside Diameter (in)" : "Height (in)";
document.getElementById("labelDim2").innerHTML = "Width (in)";
document.getElementById("labelThick").innerHTML = "Wall Thickness (in)";
document.getElementById("labelLength").innerHTML = "Total Length (ft)";
}
}
function calculateHSS() {
var shape = document.getElementById("hssShape").value;
var units = document.getElementById("hssUnits").value;
var h = parseFloat(document.getElementById("hssDim1").value);
var w = parseFloat(document.getElementById("hssDim2").value);
var t = parseFloat(document.getElementById("hssThick").value);
var L = parseFloat(document.getElementById("hssLength").value);
var density = parseFloat(document.getElementById("hssMaterial").value);
if (isNaN(h) || isNaN(t) || isNaN(L) || (shape === "rect" && isNaN(w))) {
alert("Please enter valid numeric values for all fields.");
return;
}
var area = 0; // in square meters or square inches
var weightPerUnit = 0;
var totalWeight = 0;
if (units === "metric") {
// Convert mm to meters for area calculation
var hm = h / 1000;
var wm = (shape === "rect") ? w / 1000 : 0;
var tm = t / 1000;
if (shape === "rect") {
// Area = 2 * t * (H + W – 2*t)
area = 2 * tm * (hm + wm – 2 * tm);
} else {
// Area = PI * (D – t) * t
area = Math.PI * (hm – tm) * tm;
}
weightPerUnit = area * density; // kg/m
totalWeight = weightPerUnit * L; // kg
document.getElementById("hssWeightResult").innerHTML = totalWeight.toFixed(2) + " kg";
document.getElementById("hssUnitWeight").innerHTML = "Unit Weight: " + weightPerUnit.toFixed(3) + " kg/m";
} else {
// Imperial calculation
// Steel density in lb/in3: 0.2833 (7850 kg/m3)
// Convert kg/m3 to lb/in3
var densityLbIn3 = density * 0.000036127;
if (shape === "rect") {
area = 2 * t * (h + w – 2 * t);
} else {
area = Math.PI * (h – t) * t;
}
weightPerUnit = (area * 12) * densityLbIn3; // lbs per foot (12 inches in a foot)
totalWeight = weightPerUnit * L; // total lbs
document.getElementById("hssWeightResult").innerHTML = totalWeight.toFixed(2) + " lbs";
document.getElementById("hssUnitWeight").innerHTML = "Unit Weight: " + weightPerUnit.toFixed(3) + " lbs/ft";
}
document.getElementById("hssResultBox").style.display = "block";
}
// Initialize labels
updateLabels();