The Brooklyn Bridge, Golden Gate Bridge, Mackinac Bridge, and George Washington Bridge, are among the most famous bridges in the United States.
Brooklyn Bridge
Stretching over the east River, connecting Brooklyn and Manhattan, is the awe inspiring Brooklyn Bridge.
Construction on the bridge started in January of 1870 and it opened to the public in May 1883. At the time of its opening, it was the first steel-wire suspension bridge as well as the largest suspension bridge in the world at 6,016feet.
The design of the Brooklyn Bridge was that of John Roebling, a famous bridge designer. His design was dismissed by both the city government of Brooklyn and New York. However, with the aid of some businessmen and a senator, in June 1869, two years later, his design was approved.
Roebling suffered an accident while deciding where to put one of the towers, his front foot was crushed. His toes were amputated, but a few weeks later he died of tetanus. His son Washington Roebling took over engineering of the bridge.
Ground was broke on January 3rd, 1870, with the construction of the foundation. The foundation took three years to complete and for the first time dynamite was used in bridge construction.
Washington Roebling became paralyzed due to hazards while building caissons. He continued leading the construction of the bridge from his apartment, with his wife as his messenger and a telescope so he could oversee the building.
Construction continues on to the cables and granite Gothic looking towers with arched portals. For the first time steel cables were used in construction.
The bridge opened on May 24th 1883 and 150,000 people crossed the bridge each paying one cent. One thousand eight hundred vehicles crossed the bridge that day as well, with each being charges five cents. Today there is no charge to the 145,000 vehicles and people who cross the bridge daily.
Golden Gate Bridge
Linking Marin County to the San Francisco Peninsula is the breathtaking Golden Gate Bridge.
Its name does not come from the bridge color, which is not golden or even red, but International orange. It comes from the prospectors going to the gold fields, 150 years or so ago. They would refer to the entrance of San Francisco Bay as the “Golden Gate.
Joseph Strauss was the engineer and designer in charge of the bridge construction. On January 5th 1933, construction began.
The base of the north pier of the bridge was built 20 feet below the ocean on a rock-bed. The south pier base was in open waters, 100 feet below the water. A huge watertight cofferdam was constructed and hundreds of tons of concrete were pumped into it.
The towers were finally completed in 1935 and the job of hanging the steel cables began. In 1937, two years later, the bridge construction was done. Strauss finished a short five month after the intended completion date and he was $1.3 million under budget.
During construction of the bridge, only 12 lives were lost, while 19 more were saved by a safety net. Men who were saved by the net became know as the “Half-Way-To-Hell-Club.”
When the bridge opened on May 27th 1937, 200,000 people crossed over it. Since its completion, more than one million cars have crossed.
At 26,371 feet in length, the Mackinac Bridge is the world’s third largest suspension bridge. The bridge crosses over the Straights of Mackinac, connecting the upper and lower peninsulas of Michigan.
Designed and engineered by Dr. David B. Steinman, the five-mile bridge construction employed 3500 men. Construction on the bridge began on May 7th 1954.
During construction of the bridge, only five men lost their lives. Jack Baker, Robert Koppen, Frank Pepper, James LeSarge and Albert Abbott are memorialized on a plaque at the southern end of the bridge.
Construction lasted three and a half years, opening to traffic on November 1st 1957, right on schedule. The bridge was officially dedicated on June 25th 1958, with the first “Governor’s Walk” across the bridge. Only six walkers were involved in the first Governor’s Walk, were in 1990 the numbers were as high as 70,000 walkers.
Currently The Mackinac Bridge is a toll bridge, with most of the earning going back into the bridge. It is the largest and most famous bridge on I-75 and makes a jaw dropping first impression.
George Washington Bridge
The George Washington Bridge is a two level suspension bridge. It reaches across the Hudson River, linking Fort Lee, New Jersey and upper Manhattan, New York.
Othmar H. Ammann was the bridge designer and began construction in October of 1927. The tower on the New Jersey side was built 76 feet into the Hudson River, while the tower on the New York side was built on the last due to the shorelines steep drop-off.
Each tower is made from twelve, fifty feet long steel section and rise 604 feet into the sky. The towers used more than 43,000 tons of steel and each tower leg has an elevator in it.
Originally, the towers were to be covered in decorative concrete and granite panels, to hide the steel frame. Bridge authorities abandoned this idea once seeing the natural beauty of the steelwork. This decision saved nearly one million dollars and allowed the bridge to be opened eight months ahead of schedule.
On October 25th, 1931, the bridge construction was compete and opened to the public. It cost around $52 million and the lives of twelve men. Thirty thousand people witnessed its opening.
Ammann built the bridge with expansion in mind. When opened it was a single level, six-lane bridge. In 1946, two other lanes were added and in August of 1962, a whole second level was opened.
Today the George Washington Bridge consists of two levels, the upper with eight lanes and the lower with six lanes. Around 300,000 vehicles cross the bridge daily, making it one of the busiest in the world.
The bridge was at first called the “Hudson River Bridge” and other names for it were “Palisades Bridge,” “Fort Lee Bridge,” “Verrazano Bridge,” and “Columbus Bridge.” In 1930, the Port Authority decided to name it the “George Washington Memorial Bridge.” It was later shorted to just the “George Washington Bridge.”
sources:
brooklyn.about.com
mackinac bridge.org
wikipedia
historical bridges.org
