The first suspension bridge with steel cables – the famous Brooklyn Bridge

The Brooklyn Bridge is the oldest steel cable suspension bridge built in the United States of America. It connects two important neighborhoods of New York: Manhattan and Brooklyn.

At the beginning of the 19th century, Brooklyn was nowhere near what it looks like today. We can say, rather, that it resembles, without exaggerating, a rural locality. Its population numbered 400,000 inhabitants, and New York had only one borough – Manhattan, with a population of 800,000 inhabitants. As a comparison, according to data provided by the US Census Bureau, on July 1, 2013, Manhattan has 1,626,159 inhabitants, and Brooklyn, 2.6 million people.

It is very clear that, in the 19th century, it was necessary to build a bridge to connect Manhattan to Brooklyn.

Suspension bridge with steel cable – its construction

The idea of ​​building the bridge belongs to a German immigrant, John Roebling, who had experience in the field, because in the past he had built suspension bridges. Construction work began in 1869.

Perhaps the greatest innovation brought by John Roebling was the use of steel in the construction of the bridge. The Brooklyn Bridge is the first in the world to use steel wire cables to support its suspended structure. At the time of its inauguration, it was the longest bridge on the planet. Over 15,000 kilograms of steel were used for construction.

When the steel is drawn into wires, its strength increases. A relatively flexible bundle made of steel wires is stronger than a solid steel bar of the same diameter. For this reason, steel cables are more efficient in making a suspension bridge.

When digging the foundation for the huge stone towers, the enormous wooden formwork was submerged in water. The works on caissons (construction of concrete, steel, etc., in the shape of a box that is used for the execution of foundations under water or in areas with high humidity, as well as for the repair of a ship below the waterline. Source explanation: dexonline.ro) have were extremely difficult.

After the caissons were installed on the bottom of the river, the construction of the towers continued. When they reached the maximum height of 92.2 meters above the water, the installation of the 4 enormous cables that were to support the railway began.

Brooklyn Bridge – Dimensions, installation and costs

This was the first steel cable-stayed bridge, the total length of which reached 14,568 miles.

The installation of the cables between the towers began in the summer of 1877 and was completed a year and four months later. It took another five years for the bridge to be ready for traffic and the road to be ready.

The final cost was 15 million dollars, much more than John Roebling had initially predicted. The number of people who died during the construction work on the Brooklyn Bridge is not known.

The grand opening of the bridge was on May 24, 1883.

Over a century after it was put into use, Roebling’s creation is used daily, known and admired by thousands of people. The Brooklyn Bridge allows automobile access to three lanes in each direction. It also has a wide pedestrian walkway. This is open for pedestrians and cyclists, located at a higher level than the car lanes.

The bridge is illuminated by 160 100 W bulbs.