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What is Structural Steel?

Robert Ferguson
Robert Ferguson

Structural steel is used in bridges, buildings and other types of structures throughout the world. During its manufacture, the steel is fabricated to suit a project's applicable specifications such as strength, chemical composition and shape. The main ingredients in structural steel are iron and carbon. Common additives found in addition to the iron and carbon are manganese, alloys and certain chemicals, which improve its strength and durability.

Steel is the product of mixing iron with carbon. When it is formed into particular shapes and sizes, it is referred to as structural steel. The I-beam is the most common type used today. Skyscrapers, stadiums and the ship building industry all incorporate some type of I-beam construction.

Steel I-beam.
Steel I-beam.

Various shapes, sizes and gauges can be formed out of structural steel. Common shapes include the I-beam, channels, and angles. Once manufactured, the steel is cut to length according to the project's specifications. Other forms of structural steel include rolled sheets and flat plates.

This material requires specialized equipment to cut, drill and fabricate it to applicable specifications. The steel is cut into lengths most often using a typical bandsaw. Another tool used to cut the steel into lengths or to cut irregular openings is a cutting torch. For highly specialized projects, the proper specifications are programmed into a computerized CNC coping machine. Holes are drilled into the the steel using a CNC beam drill line, which automatically feeds it along conveyors while also aligning it in the proper position for drilling.

All skyscrapers have some type of I-beam construction.
All skyscrapers have some type of I-beam construction.

Advantages to using structural steel are that it is inexpensive to manufacture, requires less maintenance, and is cheaper to insure than other traditional building methods. As long as it is protected from rust, the steel maintains its strength indefinitely. Another advantage to using structural steel is that it can be recycled. Disadvantages include higher transportation costs due to its weight, and that without proper maintenance, it is prone to rust or corrosion. It also requires large amounts of energy to produce.

Structural steel was used in the Eiffel Tower.
Structural steel was used in the Eiffel Tower.

Some examples of famous landmarks made using structural steel include the Seagram Building, the Eiffel Tower, and the Brooklyn Bridge. The Seagram Building carries the distinction of being one of the most well-engineered buildings in the world. Completed in 1889, the Eiffel Tower in Paris, France is probably the most famous steel structure in the world. The Brooklyn Bridge, completed in 1883, spans the East River in New York. The bridge connects Brooklyn to Manhattan and is a United States National Historic Landmark.

Discussion Comments


@kentuckycat - I have agree. I feel better knowing that not just the landmarks mentioned in the article are made with structural steel, but that it is so inexpensive and that it allows most engineers to be able to use it when building massive man-made structures. The reliability and in-expensive cost of structure steel should set many people's minds at ease, knowing that the structure was made with great materials, as there is no reason for the engineers to take short cuts.


@Emilski - I agree. Because structural steel is so inexpensive it allows the engineers the chance to use top of the line materials and they do not have to incur an exorbitant cost. For many people this comes as a re-assurance as they know not only that the buildings and bridges that they are in or crossing are made with top of the line materials, but that most of these structures are made with structural steel because of the inexpensive cost.


@jcraig - You are absolutely correct. Structural steel is a wonder in modern engineering as this material is so sturdy and reliable it allows buildings to last very long amounts of time and stand the test of time. Many of the landmarks that used structural steel, such as the Eiffel Tower and the Brooklyn Bridge, have had little problems with their structure and not only are still standing but still serve their purpose, with the Brooklyn Bridge still being used for travel over one hundred years after its completion.

The best thing about structural steel is that it is inexpensive and this allows it to be used more often in creating these impressive man-made structures.


Structural steel is quite an achievement in metal working. As the article states this type of steel is designed in such a way that as long as there is regular maintenance involved it will never lose its strength. This is something that is phenomenal and can make buildings stand for decades after competition.

Also, since it is inexpensive to make it is available to virtually any structure requiring steel and this allows it to be used in structures that require good sturdy work to allow it to stand the test of time.

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    • Steel I-beam.
      Steel I-beam.
    • All skyscrapers have some type of I-beam construction.
      By: Pei Lin
      All skyscrapers have some type of I-beam construction.
    • Structural steel was used in the Eiffel Tower.
      By: Kristan
      Structural steel was used in the Eiffel Tower.
    • Structural steel can be used to build a variety of constructions.
      By: Vibe Images
      Structural steel can be used to build a variety of constructions.
    • Structural steel is often used in bridges.
      By: anekoho
      Structural steel is often used in bridges.