4 Fun Facts You Didn't Know About Steel in Landmark Buildings

Steel is the most important material used in buildings and infrastructure. In fact, over 50% of steel produced goes to the construction sector.

Here are 4 fun facts about how steel plays a role in some of the most significant landmark buildings around the world:

1. Why does the Eiffel Tower grow 6 inches taller in summer?

It's crazy to know that the Eiffel Tower, one of the world’s most famous landmarks, is smaller in the winter than it is in the summer. In the winter, she (yes, it's a "she" in French) shrinks by almost six inches (15-20cm). The reason that this massive structure changes so much throughout the year is because it is made of wrought iron.

Metal changes with temperature. Steel and Iron expand with heat and shrinks in the cold, so the Eiffel Tower, the 134-year-old steel tower naturally does the same. Thus, in summer, when the thermometer is around 30°C, the tower is about twenty centimeters higher than in winter, when the structure tends to shrink.

In addition, the tower moves horizontally with heat, too. When one of its faces is in the sun, it expands, while the others remain stable. As a result, the top of the tower can make an ellipse of 15cm on a sunny day.

2. 83,000 tons of steel were used for the Golden Gate Bridge. Only half of that would be needed now.

Steel is an ever-evolving material and has gone through revolutionary changes over the years. In fact, over 75% of the 3500 steel grades in use today did not even exist 20 years ago.

Overall, the steel industry is working towards a stronger, lighter, and more sustainable direction for the material. Additionally, the production process has significantly improved over time.

That's why when the Golden Gate Bridge was built in the 1930s, it used 83,000 tons of steel. Today, that same project would require only half the amount. Steel's high strength-to-weight ratio makes it one of the most trusted bridge-building materials in the world.

3. The "shells" on the Sydney Opera House are held together with 350km of tensioned steel cable, which if laid end-to-end would reach Canberra.

Speaking of the Sydney Opera House, the first distinctive image that comes to people's minds is often the beautiful "shells" that made the roof of the building.

To create such a unique design and set the massive set of interlocking vaulted shells was one of the most challenging engineering projects ever attempted. The shells are made of 2,194 pre-cast concrete sections, but what should be used to hold all these sections? The solution is steel. With a 350km long steel tensioned cable, the most one-of-a-kind iconic Australian symbol was made.

4. New steel grades were designed to make Beijing National Stadium aka the "Bird's Nest" earthquake-proof.

Beijing National Stadium, also as known as the 'Bird's Nest', is a stunning landmark building that staged the 2008 Olympic Games as well as the upcoming Winter Olympics in 2022.

Being the world's largest enclosed space at that time, it was then also the world's largest steel structure with 26km of unwrapped steel used. A gigantic web of twisting steel sections forms the roof, creating a unique look like a bird's nest.

However, building the actual "nest" is a huge challenge as it needs to be both extremely lightweight and high-strength, especially in one of the most seismic zones in the world. 3 months of research led to 2 new steel grades specialized to make this unique design possible – Q345GDJ and Q460, produced by Baosteel and Wuhan Iron and Steel group. Thanks to advanced steel-making technology, the stadium is able to withstand an 8.0 magnitude earthquake and be extremely flexible to thermal expansion in Beijing's temperature which can range from -20℃ to 30℃.

About CUMIC

CUMIC has more than 15 years of experience in global steel trading, providing both steel mills and end-users with professional, efficient, and reliable steel supply solutions. We have established long-term cooperative relations with more than 200 steel mills to ensure these products are fabricated using quality material and are in line with various international standards.

At CUMIC, our globally experienced teams have served the buildings & infrastructure sector in over 60 countries. See some of our latest steel projects here.

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