Ground was broken for the Gateway Arch in 1959, and in 1961 the foundation of the structure was laid.
Construction of the arch itself began on February 12, 1963, as the first steel triangle on the south leg was eased into place.
These steel triangles, which narrowed as they spiraled to the top, were raised into place by a group of cranes and derricks.
The arch was to be built from 142 12-foot-long prefabricated stainless steel sections.
Once in place, each section had its double-walled skin filled with concrete.
In order to keep the partially completed legs steady, a scissors truss was placed between them at 530 feet, which was later removed as the derricks were taken down.
The whole endeavor was expected to be completed by fall 1964, in observance of St. Louis’ bicentennial.
In 1963, a million people went to observe the progress, and by 1964, local radio stations began to broadcast when large slabs of steel were to be raised into place.
President Lyndon B. Johnson and St. Louis Mayor Alfonso J. Cervantes decided on a date for the topping out ceremony, but the arch had not been completed by that date.
The ceremony date was reset to October 17, 1965, and workers strained to meet the deadline, taking double shifts, but by October 17, the arch was still not complete.
The chairman of the ceremony anticipated the ceremony to be held on October 30, a Saturday, to allow 1,500 schoolchildren, whose signatures were to be placed in a time capsule, to attend. Ultimately, the ceremony date was set for October 28, 1965.
The time capsule, containing the signatures of 762,000 students and others, was welded into the keystone section before the final piece was set in place.
Then on October 28, 1965 the arch was topped out as Vice President Hubert Humphrey observed from a helicopter.
A Catholic priest and a rabbi prayed over the keystone triangular section.
It was slated to be inserted at 10:00 a.m. but was completed 30 minutes early because thermal expansion had constricted the 8.5-foot gap at the top by 5 inches.
To mitigate this, workers used fire hoses to spray water on the surface of the south leg to cool it down and make it contract.
To insert the last keystone section, a hydraulic jack had to pry apart the legs by six feet.
By 12:00 p.m., the keystone was secured.
Some filmmakers, in hope that the two legs would not meet, had chronicled every phase of construction.
The Gateway Arch was expected to open to the public by 1964, but in 1967 the public relations agency stopped forecasting the opening date.
The arch’s visitor center opened on June 10, 1967 and the tram began operating on July 24, 1967.
The arch was finally dedicated by Vice President Hubert Humphrey on May 25, 1968.
Humphrey declared that the arch was “a soaring curve in the sky that links the rich heritage of yesterday with the richer future of tomorrow” and brings a “new purpose” and a “new sense of urgency to wipe out every slum.” “Whatever is shoddy, whatever is ugly, whatever is waste, whatever is false, will be measured and condemned” in comparison to the Gateway Arch.
About 250,000 people were expected to attend, but rain canceled the outdoor activities.
The ceremony had to be transferred into the visitor center with room for only about 500 people.
After the dedication, Humphrey crouched beneath an exit as he waited for the rain to subside so he could walk to his vehicle.
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