The process which led to the construction of the Arch began in 1933 when the
St. Louis Mayor Dickman assembled a group of businessmen who formed the
Jefferson National Expansion Memorial Association. A Joint Resolution from
Congress followed in 1934. In 1935,the City passed a $7.5 million bond issue
and, along with $9 million in WPA funds, began acquisition and clearance of a
40-block area. After this nothing significant happened until 1948 when
architectural competition was won by Eero Saarinen. Saarinen design was
for a 630 foot tall stainless steel clad catenary curve shaped arch.
Construction of the Arch began in 1963, and was completed on October 28, 1965,
for a total cost of less than $15 million. The Arch has foundations sunk 60 feet
into the ground, and is built to withstand earthquakes and high winds; it sways
up to 1 inch in a 20 mph wind, and is built to sway up to 18 inches.
| Outer Width - Outside North Leg to Outer South Leg |
630' (192m) |
| Maximum Height |
630' (192m) |
| Shape of Arch Section |
Equilateral Triangle |
| Dimension of Arch at Base |
54 ft. (16.46m) |
| Dimension of Arch at Top |
17 ft. (5.18m) |
| Size of Windows |
Approx. 7" x 27" (180 mm x 690 mm) |
| Construction of Windows |
3/4 in. (19mm) Plate Glass; Hinged and Locked |
| Size of Observation Room |
7' 2" x 65' x 6' 9" high (2.18m x 19.8m x 2.06m) |
| Capacity of Observation Platform |
100 - 140 persons |
| Deflection of Arch |
18" in 150 MPH wind (0.46 m in 240 km/h wind) |
| Method of Determining Deflection of Arch |
Calculations and Wind Tunnel Tests (240 km/h) |
| Number of Sections in Arch |
142 |
| Thickness of Plates for Outer Skin |
1/4" (6.3mm) |
| Type of Material Used in Arch Exterior |
Stainless Steel; #3 Finish Type 304 |
| Structural Capacity of Observation Area |
100 lb/sq. ft (488 kg/m) |