How to Size Steel I-Beams

Save

A steel I-beam's size describes how well it can resist compression and tension. The value that specifies this resistance to loads is the beam's area moment of inertia. This value is also known as the second moment of inertia or the bending moment of inertia, and it is unrelated to the other measure called moment of inertia, which describes objects' rotational inertia. The beam's size, or second moment of inertia, is proportional to its length and width.

Things You'll Need

  • Tape measure
  • Measure the length and thickness of each of the beam's flanges. For example, a beam's flanges may each be 5 inches long and 1.5 inches thick.

  • Measure the length and thickness of the steel between the flanges. For example, this steel stretch may measure 7 inches long and 2 inches wide.

  • Raise each length to the power of 3 and multiply each by the steel's thickness: 5³ --- 1.5 = 187.5; 7³ --- 2 = 686.

  • Add the twice the answer for the beam's flanges to the answer for the steel between them: (187.5 --- 2) + 686 = 1,061.

  • Divide this answer by 12, a conversion constant: 1,061 ÷ 12 = 88.4. This is the beam's second moment of inertia, measured in inches raised to the power of 4.

Related Searches

References

  • Photo Credit Comstock/Comstock/Getty Images
Promoted By Zergnet

Comments

Resources

You May Also Like

  • Standard Steel C Channel Sizes

    American Standard steel channels come in a variety of categories. Sizes for steel channels in the C category have been standardized. Information...

  • How to Calculate Support Beam Sizes

    In construction, engineers must deploy support beams to counter-balance weights. For example, imagine a beam, say 10 meters long, that's stretched from...

  • How to Calculate for Steel I Beams

    Engineers use a structure's area moment of inertia to describe how well it resists load stresses. A beam with a higher area...

  • How to Size Structural I Beams

    I-beams get their name because they are shaped like the letter "I" with two horizontal beams on top of a vertical beam....

  • How to Calculate Moment of Inertia of Steel Beams

    Multiple quantities in mechanics go by the name "moment of inertia." The rotational, or polar moment of inertia of a solid describes...

  • How to Size H-Beams

    An H-beam is composed of three sections. Two parallel flanges form the ends of the beam, and a stretch of metal, the...

  • How to Determine a Steel Beam Size

    The size of steel beams chosen in residential and commercial construction projects is critical to the integrity of the structure they are...

  • I-Beam Specifications for a Bridge Crane

    Bridge cranes move large loads of materials in a lateral direction down a bridge, girder, or beam that travels in a longitudinal...

Related Searches

Check It Out

3 Day-to-Night Outfits for the Work Week

M
Is DIY in your DNA? Become part of our maker community.
Submit Your Work!