How to Calculate a Steel I-Beam’s Weight

5 January 2020

Steel I-Beams have been used in both construction and storage since the first half of the 19 th century. Although they have suffered some adjustments, they haven nevertheless remained popular to this day, thanks, in part, to their extraordinary utility in terms of carrying both shearing and bending loads.

Most of the buildings we see in our cities, as well as most pallets racks in warehouses rely on the strength of steel I-Beams to support extreme weights. However, precise measurements must be made to ensure that these beams are not overburdened. Otherwise, any system of I-Beams becomes weakened in time and can even collapse due to improper maintenance.

What Is a Steel I-Beam?

Also known as the Standard American Beam, the steel I-Beam looks like an “I” when viewed in cross-section. Each steel beam consists of the following two components:

  • A vertical element referred to as the “web.”

  • Two horizontal elements known as the “flanges.”

Steel I-Beams can support very heavy weights due to these two melded components working together. While the web is designed to carry most of the shear forces, the role of the flanges is to absorb any bending moments applied to the beam.

The advantages of using steel I-Beams in construction, civil engineering, and storage include:

  • These structures are extremely resilient and cannot be weakened by termites or rodents (unlike wood).

  • The steel is capable of enduring high tensile stress, which means breakages are unlikely to occur, even in the long-run.

  • Steel I-Beams are not severely affected by corrosion or fire.

  • When used correctly, these structures uphold the highest standards of safety and structural integrity.

When using steel I-Beams in storage, however, emphasis should be placed on whether or not the structures are overloaded. Since this should be avoided at all costs, one must be able to calculate the weight of an I-Beam in order to come up with an accurate review of the entire racking system.

How to Measure an I-Beam Correctly

To measure a steel I-Beam’s weight, you must first determine its correct volume, which you can then multiply by the weight density of steel. For an accurate measurement, consider all three components of the I-Beam (the web and the two flanges) as separate entities with unique length, width, and height.

First, you should measure the length of the web in inches or meters, which will also give you the length of the flanges. For example, let’s assume that the three components are 3 meters long. Then, consider the height and thickness (or width) of the central component (the web, as viewed from a cross-section). Let’s assume that these are 0.4m and 0.1m.

Finally, you can move on to the two flanges, which usually feature the same measurements, but should be considered separately for better accuracy. In our particular example, they might be 0.05m wide and 0.25m high.

Now that you have the precise measurements for each component, you can easily calculate their respective volumes. Do this by multiplying the length by the width by the height of each individual component. Our I-Beam’s web, for instance, has a volume of 3m x 0.4m x 0.1m or 0.12 cubic meters. The I-Beam’s flanges, on the other hand, have a volume of 3m x 0.25m x 0.05m or 0.0375 cubic meters.

When you add the three volumes together, you obtain the total volume of the steel I-Beam. In our case, this is 0.195 cubic meters.

How to Determine a Steel I-Beam’s Weight

The final step to calculating a steel I-Beam’s weight is to multiply its volume in cubic meters by the weight density of steel. The latter measurement depends on the type of steel you’re working with, but will, in general, be in the range of 7750 kg/cubic meter and 8050 kg/cubic meter.

Our I-Beam, for example, should weigh no more than 0.195 cubic meters x 8050 kg/cubic meteror 1569.75 kg. You can easily convert this measurement into any unit, including pounds (1kg is approximately 2.205lbs).

One very important factor to consider when calculating volumes and weight is that the unit of measurement must remain constant. Density is usually measured in kg/cubic meters or in lbs/cubic foot, which means that you must ultimately comvert your I-Beam’s volume to either cubic meters or cubic feet (in case you were measuring in centimeters or inches) in order to obtain an accurate result in kgs or lbs, respectively.