Bridges are, and will continue to be, the original information super highway. Whether spanning long distances or a few hundred feet in length, a bridge connects people, towns, cities, cultures, industry and commerce. There is something remarkable about crossing a wide river like the Mississippi to get to a destination. They are monuments to mankind’s ability, courage, and engineering skill. The following post features two well-known and visited bridges.
|The Brooklyn Bridge||The Golden Gate Bridge|
|Twisted cable suspension engineering||Twisted cable suspension engineering|
|Connects two NYC Boroughs||Connects San Francisco and Marin County|
|Known worldwide||Known worldwide|
|Longest suspension bridge upon completion||Longest suspension bridge upon completion|
|Pedestrian access||Pedestrian access|
|History of suicide jumps||History of suicide jumps|
|First steel suspension bridge||Steel shipped from East Coast ports through Panama Canal to West Coast|
|27 men lost their lives during construction||11 men lost their live during construction|
THE BROOKLYN BRIDGE
The Brooklyn Bridge was completed in 1883 and connects Manhattan and Brooklyn, New York. The bridge’s main span is 1595.5 feet and was the longest suspension bridge when completed. John Roebling, a German immigrant, and bridge designer and engineer, began work on the project. He sustained an injury while conducting surveys resulting in an amputation that developed a tetanus infection that eventually killed him. His son, Washington Roebling, continued the project.
Unfortunately, Washington Roebling sustained a paralyzing injury himself due to decompression sickness soon after the construction phase began on Jan 3, 1870. What is fascinating about the construction is that Washington Roebling’s wife, Emily Warren, stepped in to act as a liaison during construction. Washington Roebling was incapacitated so Emily Warren communicated engineering plans to the staff building the bridge. Under Washington Roebling’s guidance Warren communicated strength calculations, catenary curves. bridge specifications, and cable construction designs. She assisted her husband for the next 11 years.
Roebling used airtight caissons that were made like massive wooden boxes. The wooden boxes were sent to the bottom using giant granite blocks. The
chamber was pressurized so that water and debris would be kept out. They didn’t know enough about how pressurized air affected a person’s internal organs upon ascending to the surface too quickly. This is what is known today as the “bends” when too much gas forms bubbles in the bloodstream. Many were killed or injured during this process. These workers were known as “sand-hogs” and earned $2 a day. However, despite the dangers, they stuck with the process. Once they cleared away the debris and reached the bedrock, they started the process of laying the granite for the towers that were used for the suspension cables.
Roebling built the bridge so that it would be six times stronger than needed. It is one reason the bridge is still standing today after so much vehicular and pedestrian traffic.
The Brooklyn Bridge was opened for use on May 24, 1883. On first day for crossing 1,800 vehicles and 150,300 people travelled between Manhattan and Brooklyn. Emily Warren Roebling was the first to cross the bridge. Emily Warren Roebling died of stomach cancer in 1903. Washington Roebling died on July 21, 1926. He fought the effects of caisson’s disease the remainder of his life..
THE GOLDEN GATE BRIDGE
The Golden Gate Bridge spans the Golden Gate Strait and is the entrance to the San Francisco Bay from the Pacific Ocean. The Golden Gate Bridge construction phase began on Jan.5, 1933 and was open to traffic on May 28, 1937. Pedestrians were able to cross on May 27, 1937. Ten different prime contractors and their subcontractors worked on the bridge construction. During the construction, 11 men lost their lives but 19 men were saved due to the project using safety nets. The men who were saved by falling into the nets are known as the “Halfway-to-Hell Club.”
According to historical documents, the steel used in the construction of the bridge was manufactured by Bethlehem Steel in plants in Trenton, New Jersey and Sparrows Point, Maryland and in plants in three Pennsylvania towns: Bethlehem, Pottstown, and Steelton. The steel was sent to Philadelphia and shipped through the Panama Canal to San Francisco.
The construction design relies on cable suspension that passes through two main towers. The weight of the roadway is hung from two cables that pass through the two main towers and are fixed in concrete at each end. Each cable is made of 27,572 strands of wire. There are 80,000 miles (129,000 km) of wire in the main cables.The bridge has approximately 1,200,000 total rivets.
Engineers working on the project used a “deflection theory” design that reduced stress by transmitting forces through suspension cables to the bridge towers. The project cost more than $35 million. The project was finished by April 1937 and came in $1.3 million under budget.
The color of the bridge is officially an orange vermillion or international orange. Since 1990 acrylic topcoats have been used for air-quality reasons. The program was completed in 1995 and it is maintained by 38 painters who re-paint the areas where it becomes eroded.
Both the Golden Gate and Brooklyn Bridges are majestic when viewing or crossing over them. The workers who died while making these structures deserve to be remembered. The talented engineers and hard-working construction people who completed the bridge also deserve a “job well done!” from each citizen who walks, rides or travels across these bridges.
What are your names of your favorite bridges? Leave a comment and let me know.