In this blog post, I will focus on the reasons why the H-beam is structurally superior and the principles behind why the H-shape makes for an efficient structure, proofreading and editing the text to ensure it flows naturally and is easy to read.
Korean actor Lee Byung-hun once caused a major stir when he said in a commercial, “I can say with certainty that metal is the most perfect material.” Ever since humanity moved beyond the Stone Age and entered the Bronze and Iron Ages, metal has been one of the most useful materials to people. And even in today’s information-driven society, iron continues to quietly underpin our lives behind the scenes. However, I’d like to take this a step further and argue that metal—and iron, in particular—exists in the most perfect form. I can say with certainty: the H-shape is the most perfect form!
The question “What does it look like?” is a very important one for us. Looking at the case of Steve Jobs, who patented the iPhone’s design and engaged in fierce litigation over it, we can see that the form of an object is determined after countless deliberations and research. From round wheels and rectangular books to triangular pyramids and even round manhole covers. In this way, the form of nearly every object around us embodies the deliberations of many people. However, to the point where such deliberations seem almost irrelevant, most objects are based on basic shapes—such as circles, triangles, and squares—that we learned in elementary school math class. Yet, unlike ordinary objects, the H-beams used in steel-frame structures have a very unique shape—and that shape is the perfect “H.”
If you look at the framework of a building under construction, you’ll see that it’s mostly made up of H-beams. A building with only its skeleton exposed gives the impression that one might cut oneself at any moment, as the sharp sheen of the steel blends with the edges of the H-beams. At first glance, one might wonder if it’s really safe to use steel this thin. Surprisingly, however, this thin and seemingly lightweight H-shape withstands loads far more efficiently than a solid rectangular cross-section.
When designing bridges or buildings—not only in South Korea but around the world—the most critical consideration is the ability to withstand downward pressure. In other words, the key lies in how well the structure resists deformation. When subjected to force, all materials expand or contract proportionally, generating a force that resists that change. Steel is no exception, but it requires a much greater force than many other materials to produce the same amount of deformation. Furthermore, a perfect H-shape is one of the structures that requires the greatest force to produce the same amount of deformation while using the same amount of material, giving it exceptional structural efficiency.
Consider the phenomenon of steel bending: when a load is applied from above, the upper part is compressed and the lower part is stretched relative to the center of the cross-section. The change in length becomes greater the farther away from the center, and the greatest deformation occurs at the outermost edges. As explained earlier, the greater the deformation in a section, the greater the resistance it generates. Therefore, the top and bottom surfaces—which are farthest from the center—play the most critical role in supporting the structure.
Now, let’s consider a simple math problem. What is the largest number that can be formed using 1, 1, 10, 10, and the operators +, ×, and ×?
The answer is 101. (1 × 1 + 10 × 10 = 101) On the other hand, if we pair 1 and 10 separately, the result is only 1 × 10 + 1 × 10 = 20. Even though the only difference is how the numbers are paired, the result differs by more than five times.
Through this simple calculation, we can see that the highest efficiency is achieved when large values are combined with large values and small values with small values. Applying this to steel structures, the most efficient way to use a limited amount of steel is to place only the minimum amount of material in the center—where deformation is minimal—and concentrate most of the material at the top and bottom, where deformation is greatest. The H-beam is the structure that best embodies this principle.
Consider the phenomenon of steel bending: when a load is applied from above, the upper part is compressed and the lower part is stretched relative to the center of the cross-section. The change in length becomes greater the farther away from the center, and the greatest deformation occurs at the outermost points. As explained earlier, the greater the deformation in a section, the greater the resistance it generates. Therefore, the top and bottom surfaces—which are farthest from the center—play the most critical role in supporting the structure.
Now, let’s consider a simple math problem. What is the largest number that can be formed using the numbers 1, 1, 10, 10 and the operators +, ×, and ×?
The answer is 101. (1 × 1 + 10 × 10 = 101) On the other hand, if we pair the 1 and 10 separately, the result is only 1 × 10 + 1 × 10 = 20. Even though the only difference is how the numbers are paired, the result differs by more than five times.
Through this simple calculation, we can see that the highest efficiency is achieved when large values are combined with large values and small values with small values. Applying this to steel structures, the most efficient way to use a limited amount of steel is to place only the minimum amount of material in the center—where deformation is minimal—and concentrate most of the material at the top and bottom, where deformation is greatest. The H-beam is the structure that best embodies this principle.
This difference becomes even more apparent when comparing two beams with the same cross-sectional area. Even when using the same amount of steel, an H-beam can secure a greater distance from the center to the top and bottom flanges. In structural mechanics, as this distance increases, the resistance to bending improves significantly. Therefore, even when using the same amount of material, an H-beam can withstand much heavier loads. In other words, the H-beam is a highly efficient structure that achieves greater rigidity with less material.
Of course, H-beams are not the only type of steel used in everyday life. Depending on the application, various steel sections—such as U-beams and T-beams—are used, and each shape is designed to meet specific requirements. These shapes also offer advantages such as ease of fabrication and assembly or better suitability for specific environments. Nevertheless, in structures that form the framework of buildings and bridges, H-beams play a crucial role based on their outstanding structural efficiency. In short, the H-shape is the most perfect form.
