Gateway Arch in St. Louis Completed

The Gateway Arch, also known as the Gateway to the West, is part of the Jefferson National Expansion Memorial in St. Louis, Missouri.

Built as a monument to the westward expansion of the United States, it has become the city's iconic image. It was designed by Finnish-American architect Eero Saarinen and structural engineer Hannskarl Bandel in 1947. It is 630 feet (192 m) wide at its base and stands 630 feet (192 m) tall, making it the tallest monument in the United States. Construction started on February 12, 1963, and ended on October 28, 1965. The monument opened to the public on July 10, 1967.

The design of the Arch was chosen in a national architectural competition in 1947 from among 147 entries. The competition was coordinated by architect George Howe, and the seven jury members included Fiske Kimball, Richard Neutra, Roland Wank, and William Wurster. After narrowing the field down to a smaller number of finalists, Saarinen's design was chosen unanimously.

The cross-sections of its legs are equilateral triangles, narrowing from 54 feet (16 m) per side at the base to 17 feet (5.2 m) at the top. Each wall consists of a stainless steel skin covering a sandwich of two carbon steel walls with reinforced concrete in the middle from ground level to 300 feet (91 m), with carbon steel and rebar from 300 feet (91 m) to the peak. The Arch is hollow and contains a unique tram system that brings visitors to an observation deck at the top. The interior also contains two stairwells of 1,076 steps each for use in emergencies.

The base of each leg at ground level had an engineering tolerance of one-64th of an inch (0.40 mm) or the two legs would not meet at the top. During construction, both legs were built simultaneously. When the time came to connect the legs at the apex, thermal expansion of the sunward-facing south leg prevented it from aligning precisely with the north leg. The St. Louis Fire Department sprayed the south leg with water from firehoses, cooling it until it aligned with the north leg.

The tram is an egg-shaped "elevator". It is operated by the quasi-governmental Bi-State Development Agency under an agreement with the NPS (National Park Service).
From the visitor center, one may move to either base (one on the north end and the other on the south end) of the Arch and enter the tramway much as one would enter an ordinary elevator, through narrow double doors. The north queue area includes displays that interpret the design and construction of the Gateway Arch; the south queue area includes displays about the St. Louis riverfront during the mid-19th century.

Passing through the doors, passengers in groups of five enter an egg-shaped compartment containing five seats and a flat floor. Because of the car shape, the compartments have sloped ceilings low enough to force taller riders to lean forward while seated (for this reason it's recommended that the tallest of the five passengers in the car sit in the center seat facing the door). Eight compartments are linked to form a train, meaning that both trains have a capacity of 40, and that 80 people can be transported at one time. These compartments rotate 5 degrees as they travel, keeping them upright while the entire train follows curved tracks up one leg of the arch. The trip to the top takes four minutes, and the trip down takes three minutes. The car doors have narrow windows, allowing passengers to see the interior stairways and structure of the Arch during the trip.

On October 8 in 1965, construction is completed on the Gateway Arch, a spectacular 630-foot-high parabola of stainless steel marking the Jefferson National Expansion Memorial on the waterfront of St. Louis, Missouri. The Gateway Arch, designed by Finnish-born, American-educated architect Eero Saarinen, was erected to commemorate President Thomas Jefferson's Louisiana Purchase of 1803 and to celebrate St. Louis' central role in the rapid westward expansion that followed. As the market and supply point for fur traders and explorers--including the famous Meriwether Lewis and William Clark--the town of St. Louis grew exponentially after the War of 1812, when great numbers of people began to travel by wagon train to seek their fortunes west of the Mississippi River. In 1947-48, Saarinen won a nationwide competition to design a monument honoring the spirit of the western pioneers. In a sad twist of fate, the architect died of a brain tumor in 1961 and did not live to see the construction of his now-famous arch, which began in February 1963. Completed in October 1965, the Gateway Arch cost less than $15 million to build. With foundations sunk 60 feet into the ground, its frame of stressed stainless steel is built to withstand both earthquakes and high winds. An internal tram system takes visitors to the top, where on a clear day they can see up to 30 miles across the winding Mississippi and to the Great Plains to the west. In addition to the Gateway Arch, the Jefferson Expansion Memorial includes the Museum of Westward Expansion and the Old Courthouse of St. Louis, where two of the famous Dred Scott slavery cases were heard in the 1860s. Today, some 4 million people visit the park each year to wander its nearly 100 acres, soak up some history and take in the breathtaking views from Saarinen's gleaming arch.