A Marvel of Steel Construction: The Gateway Arch and the Historic Journey It Symbolizes

St Louis Gateway Arch over a river

In 1804, the Corps of Discovery led to set out westward to map out the land the U.S. had acquired through the Louisiana Purchase. Merriwether Lewis and William Clark, two trained land surveyors and soldiers, gathered up a group of 45 souls. Most of them enlisted soldiers— to accompany them on a treacherous and unknown journey through these unexplored lands. What better landmark to commemorate such a journey than a marvel of steel construction exemplified by the Gateway Arch in St. Louis? This steel and concrete structure coming in at 17,246 tons is a testament to the versatility and durability achieved with proper steel construction. 

What is the Meaning Behind the Famous Steel Gateway Arch? 

The Gateway Arch attracts thousands of people every year. This unique steel structure commemorates a very specific moment in history that would change the course of the United States forever. That historical moment was the moment that President Jefferson summoned Merriwether Lewis to lead the expedition westward and collect information about the new land. Lewis then sought out his partner William Clark to help him lead the excursion.

President Jefferson instructed the team to map out the area, record latitude, and longitude, observe the land, animals, plant life, and the native peoples along the way. Along their journey, the team confronted swarms of mosquitoes, fleas, harsh river currents, heat, bitter winters, dehydration, fatigue, and frostbite. They also encountered various Native American tribes, some friendlier and more welcoming than others. During their trip, Lewis & Clark collected botanical samples, observed the wildlife and prairies, and learned a great deal about the new lands. They returned to St. Louis in September of 1806 to a hero’s welcome. 

A Testament to the Beauty and Longevity of Steel Construction 

St. Louis Arch was built in 1963, and not only does it commemorate the grit of the Corps of Discovery, but it is a standing testament to the skill of the steel fabricators. Especially for its time, the arch is unlike any other steel structure as it represents the unique capabilities possible with innovative steel construction. 

The Arch was designed by the American-Finnish architect Eero Saarinen. When it was first designed, many people doubted the architect, doubtful that the structure would stand. The team of engineers, workers, and architects, however, proved the haters wrong. 

How Was the Steel Gateway Arch Built? 

Primarily constructed from steel and concrete, the Gateway Arch stands at about 630 feet high. The foundations of the structure go down about 60 feet deep. The structure was erected section by section with a total of 142 sections. The engineers designed it to be hollow, and this allowed for the construction of the tramway, which allows visitors to get on top of the structure and see into the St. Louis skyline. 

Here are a couple of amazing facts regarding steel construction:                                                   

  • The Arch has a hollow core, and each leg is a double-walled equilateral triangle. The shape helps give it stability. 
  • The inner lining of the Arch is composed of A-7 carbon steel and is ⅜ inches thick. 
  • The outside lining and surface is derived from 900 tons of polished stainless steel
  • Special welding techniques were employed to ensure the proper joining of the stainless steel plates

Innovative Techniques of Steel Construction 

Engineers of the Gateway Arch had to account for winds and harsh weather, ensuring that the structure would not only remain standing but had enough flexibility to sway and remain robust. The Arch is designed to sway up to 18 inches. For sections that are high up in the 300-foot level, special strength steel bolts were attached. All of the sections were welded together. 

In order to resist bending, the outer and inner skin or lining of the steel is similar to what is now commonly used in aircraft design, creating a tight seal. 

How’s This For Precision and Architectural Insight?

The construction of the Arch was largely done separately and in pieces. That meant that measurements had to be precise. Every detail had to be considered and verified again and again. 

  • The legs of the Arch were built separately, which meant that if measurements were off by 1/64th of an inch, it would have spelled catastrophe. 
  • The margin of error allowed for any measurement was less than one millimeter, meaning that engineers had to work diligently and precisely. 
  • Although the insurance company was braced for at least 13 deaths during construction, no one died building the Arch. 
  • The arch is 630 feet wide and 630 feet high.

Steel Construction for Your Building Projects Will Stand the Test of Time 

While you might not be building a 630-foot high steel arch, your business or factory might need quality steel fabrication. Steel Specialties can help you with your steel needs. From structural steel to steel fabrication or steel plates, we got you covered. 

Have questions about our steel services? Need steel construction or fabrication for your next project. Call Steel Specialties today and learn more about what we do.