Many of us have heard about the Seven Wonders of the Ancient World (Pyramids of Egypt, Hanging Gardens of Babylon, Lighthouse of Alexandria, etc.). However, some people may not know that the American Society of Civil Engineers (ASCE) compiled a list of the Seven Wonders of the Modern World as a tribute to civil engineering achievements of the 20th century:
- Golden Gate Bridge (San Francisco)
- Netherlands North Sea Protection Works (Netherlands)
- Itaipu Dam (Brazil/Paraguay)
- CN Tower (Toronto)
- Channel Tunnel (England & France)
- Empire State Building (New York)
- Panama Canal (Panama)
We invite you to join us in a seven-part series as we explore and learn more about these modern feats of amazing engineering. We look forward to learning more about the legacy of engineers in the 20th century and how they have overcome the impossible and improved the world!
Spanning the Golden Gate strait and connecting the City of San Francisco and Marin County in California, the Golden Gate Bridge was the longest suspension bridge main span in the world until 1964. With a total length of about 1.7 mi, the Golden Gate Bridge provided a short, practical link with other communities around the bay. Before construction, San Francisco’s growth rate was below average.
Joseph Strauss was the Chief Engineer in charge of overall design and construction. Because of his lack of understanding and experience with cable-suspension designs, the final design can be credited to Leon Moisseiff. Moisseiff collaborated with scholar and mathematician Charles Ellis, who did much of the technical and theoretical work for the project.
Despite opposition from the Department of War, federal land was donated for the project and construction began January 5, 1933. $35 million later, the Bridge opened to traffic May 28, 1937.
- The Golden Gate Bridge has only been closed three times because of weather
- The U.S. Navy originally wanted the bridge to be painted black with yellow stripes, instead of its unique “International Orange”
- In 1965, paint corrosion on the bridge sparked a program to remove the original lead-based paint and replace it with an inorganic zinc silicate primer and acrylic emulsion topcoat
- There are approximately 600,000 rivets in each tower
- When original rivets become corroded, they are replaced with ASTM A-325 high-strength bolts of equal diameter
- The speed limit on the bridge has been 45 mph since 1983
- There are 80,000 miles of wire in the main cables
- As of January 2014, approximately 2,025,883,491 vehicles have crossed the Golden Gate Bridge (includes northbound and southbound) since opening to traffic on May 28, 1937
- Recently (January 2015), a moveable median barrier was successfully installed on the Bridge
The Golden Gate Bridge has also been featured in countless movies, television shows and other media. Whether for entertainment or academic purposes, there are many interesting facts and figures relating to this modern engineering marvel.
Have you traveled to one of the modern engineering marvels? Check out our Facebook page and let us know about your experience!