How to Size H-Beams

H-beams form building frames.
••• Comstock/Comstock/Getty Images

An H-beam is composed of three sections. Two parallel flanges form the ends of the beam, and a stretch of metal, the beam's webbing, runs between them. The lengths of these sections can withstand compressive forces, letting the H-beam bear a significant load without bending. The beam's size describes its overall resistance to bending forces. This value, the beam's area moment of inertia, is the product of the beam's dimensions, and it takes the unit of length raised to the power of 4.

    Raise the length of each of the H-beam's flanges to the power of 3. For example, if each flange is 6 inches long: 6^3 = 216 in^3.

    Multiply this answer by the width of a flange. For example, if each flange is 2 inches thick: 216 × 2 = 512 in^4.

    Double this answer because the beam has two flanges: 512 × 2 = 1,024 in^4.

    Repeat Steps 1 to 3 with the webbing between the flanges. For example, if the webbing is 6.5 inches long and 2.2 inches wide: 6.5^3 × 2.2 = 604.18 in^4.

    Add together the previous two steps' answers: 1,024 + 604.18 = 1,628.18 in^4.

    Divide this sum by 12: 1,628.18 / 12 = 135.68, or just over 135 in^4. This is the H-beam's area moment of inertia.

Related Articles

How to Calculate for Steel I Beams
How to Convert Square Dimensions to Round
How to Find the Area of a Rectangular Prism
How to Find the Area & Width of a Rectangle
How to Calculate Rebar Lengths
How to Size Gravity Drainage Piping
Characteristics of Aquatic Plants
How to Calculate the Obtuse Triangle
How to Measure Area
How to Calculate Oil Tank Volume
How to Calculate Torsion Constant
How to Measure the Length of the Diagonal Line of a...
How to Find Dimensions in Geometric Shapes
How to Describe a Shape in Terms of Its Area and Perimeter
How to Test Electrical Conductivity
How to Calculate Triangle Dimensions
How to Calculate Pyramid Angles
How to Find the Surface Area of a Triangular Prism
How to Find the Radius of a Circle With the Midpoint
How to Split a Triangle Into Fourths

Dont Go!

We Have More Great Sciencing Articles!