Despite having lived across from the Gateway Arch for the first three months that I was in the US, it has taken almost a year & a half to get ‘up close & personal’ with what is probably the most famous attraction in St Louis.
The Arch, or rather ‘The Jefferson National Expansion Memorial’ is a monument to westward expansion in the USA & actually consists of the Gateway Arch, the Museum of Westward Expansion (which is located under the arch), & St. Louis' Old Courthouse (which is west of 4th).
There was a nationwide competition in 1947-1948 to design a monument in St Louis honouring western pioneers. The winner was the architect Eero Saarinen who won the competition with his sleek, stainless steel, arch.
A few arch facts:
The Arch is the tallest national monument in the United States at 630 feet, & is the tallest thing in St Louis (the city will not allow anything taller to be built).
Construction began February 12, 1963 & the last section of the Arch was put into place on October 28, 1965.
The foundations for the Arch are 60 feet deep.
Nine hundred tons of stainless steel was used to build the Arch.
The shape of the Arch is an inverted catenary curve. A catenary curve is the shape that a free-hanging chain takes when held at both ends, & was named by the Dutch mathematician Christiaan Huygens from the Latin word ‘catenarius’, which means ‘related to a chain’. The span of the Arch legs at ground level is 630 feet, the same as its height.
The Arch is triangular in section. The two bases are equilateral triangles (each side is 54 feet long). At the top of the arch, the sides of the triangle are 17 feet long.
In order to ensure that the constructed legs would meet, the margin of error for failure was 1/64th of an inch. All survey work was done at night to eliminate distortion caused by the sun's rays.
Each year, approximately a million visitors ride the trams to the top of the Arch. The trams have been in operation for over 30 years, traveling a total of 250,000 miles & carrying over 25 million passengers.
There are 1076 steps in each arch leg that are for emergency use only.
The Arch was built at a cost of $13 million. The transportation system was built at a cost of $3,500,000.
The Arch sways a maximum of 18" (9" each way) in a 150 mph wind. The usual sway is 1/2".