Return to Scale View
About

How big is the Gateway Arch?

192 meter!

View History Report
Gateway Arch

The Gateway Arch is a stainless steel arch beside the Mississippi River in St. Louis, Missouri. It is 192 meters (630 feet) tall, and as wide as it is tall: its two legs stand 192 meters apart at ground level. The Finnish-American architect Eero Saarinen designed it, and it was completed in 1965.

Size

The National Park Service, which looks after the arch, gives its height as 630 feet (192 meters). The distance from one leg to the other at ground level is also 630 feet (192 meters), so the arch is exactly as wide as it is tall. The Park Service counts 10 feet for each story of a building, which makes the arch 63 stories tall.

Each leg is a hollow triangle in cross-section, with walls made of two layers of steel. The outer layer is polished stainless steel, and the inner layer is carbon steel. The triangular sections are largest at the base and get smaller toward the top. The concrete foundations reach 18 meters (60 feet) into the ground, half of that depth in solid bedrock.

Size comparisons

  • At ground level the legs stand 1.75 times as far apart as the length of an American football field, which is 110 meters (120 yards) long including the end zones.
  • The arch is about 23 meters (75 feet) taller than the Washington Monument, which is 169 meters (555 feet) tall.
  • It is about twice as tall as the Statue of Liberty, which measures 93 meters (305 feet) from the ground to the tip of its torch.
  • The Eiffel Tower, 330 meters (1,083 feet) tall, is about 1.7 times the height of the arch.

Why the arch has this shape

The curve of the arch is based on a catenary, the shape a chain or rope takes when it hangs between two points. Saarinen used a weighted catenary. It follows an imaginary chain whose links are heavier at the ends than in the middle, which makes the arch rounder than a plain catenary. The Park Service describes the weighted catenary as the strongest type of arch, because the push of its weight travels down through the legs into the foundations.

The arch has no frame inside it. Its steel skin carries its own weight. Up to a height of 300 feet (91 meters), the space between the two layers of steel is filled with concrete. Above that it is hollow, braced with steel. Keeping most of the weight low reduces sway. The structural engineers reported that a wind of 150 miles per hour (240 kilometers per hour) would move the top only 18 inches (46 centimeters).

How the arch was built

Saarinen's design was chosen from 172 entries in an architectural competition. The arch stands for Thomas Jefferson's vision of a nation stretching across the continent, and for St. Louis's role as a gateway to the American West in the 1800s. Construction began on February 12, 1963, and the arch was completed on October 28, 1965.

Both legs rose at the same time, without scaffolding. Above 22 meters (72 feet), cranes that climbed the curved legs lifted each new section, 3.7 meters (12 feet) high and weighing about 45 metric tons (50 US tons). At the 530-foot (162-meter) level, a steel truss 78 meters (255 feet) long was set between the legs to brace them against each other while the last sections were added. Visitors now ride to an observation room at the top in trams made of eight small capsules, each seating five people.

Sources

De schaal van het Universum > Gateway Arch
Washington Monument
The Washington Monument is the world's tallest obelisk, as well as the world's tallest stone structure. It was the world's tallest structure from 1884 to 1889. After that it was the Eiffel Tower, which is to the upper-right.
Great Pyramid of Giza
This picture is actually of the Giza Necropolis. The Great Pyramid of Giza is the pyramid on the left. It is the oldest one, built by the Egyptians in 2560 BC. It was the tallest man-made structure for almost 4,000 years.
Saturn V
Saturn V is the tallest and heaviest rocket ever! That's pretty cool. It was used from 1968-1972 and was the only vehicle used to launch humans far away from the Earth, to places such as the Moon.
Hoover Dam
The Hoover Dam, which was built on the Colorado River, holds in the largest reservoir in the United States, Lake Mead. Not only does the Hoover Dam provide water, but its turbines also generate electricity.
Titanic
The Titanic sank when it hit an iceberg. Although it was capable of holding enough lifeboats for 4,000 people, they decided they only needed enough lifeboats for 1,178 people. There were 2,228 people on the Titanic.
AM Radio Wavelength
A and M are the first and thirteenth letters of the alphabet. One is a perfect square, while thirteen is not. We all have our differences, and we have to learn to accept them. That's the only way we'll live in harmony.

Discussion