The Bosphorus Bridge, a suspension bridge connecting the two continents; Europe and Asia. Here are the enormous dimensions. Total length is 1560 meters. Width is 33 meters. The clearance from sea level is 64 meters. The height of its towers is 165 meters. But how this gigantic bridge built? The Bosphorus Bridge, in fact, was a massive project that was first developed during the reign of Sultan Abdul Hamid II in 19th century but its construction couldn’t be completed before 1970. The construction basically consisted of 5 stages. Construction of towers’ foundations and anchor blocks. Steel towers. The main support cable. The suspended-deck. And the approach viaducts.
Construction began with the towers’ foundations. Foundations, which were concrete cylinders having a diameter of 18 meters, were founded on solid rock a depth of between 17 and 24 meters. Following the foundations, there began the construction of anchor blocks. The function of these blocks was to support the main cable, thus transferring the tensile strength of the cable to the solid rock. During construction of the blocks, some steel bars were embedded into the concrete. After towers’ foundations, it began the mounting of steel towers.
These towers 165 meters high have 2 piers. The piers were built in 10 stages. At every stage, 4 steel panels were connected by pylons thus getting a hollow box section. The steel panels were brought from Italy, and a total of 5,000 tons of steel was used. Next was the main cable. The hangers were made of steel. With the help of anchorage and towers, the load was transferred to the ground. The main cable consisted of 10,412 steel wires with a diameter of 5 mm. Its total width is 58 cm, and the weight 6,100 tons. A catwalk was built between towers to lay the cables.
The most important feature of the Bosphorus Bridge is its suspended-deck. The reason why this system was preferred is because it reduces the effects of the wind by one third. After being welded together on the building site in a district called Goksu the deck units were brought to the sea. That was the hardest part of all. The deck units were carried to the construction site on a barge and lifted up by some special cranes. They were attached to the vertical cables hanging from the main cable and welded together. After the approach viaducts 15 m long were built between towers and anchorage a 19-cm-thick pavement made of reinforced concrete was laid over the steel structure.
Finally, a 38-mm-thick mastic asphalt was applied on the pavement, just like on the deck structure. The bridge with its tolls and facilities was opened on October 29th, 1973. The Bosphorus Bridge has been carrying people between two continents for almost 40 years.