- Striking features about the Bosphorus Bridge: A technical trip was organized to the 408rd Bosphorus Bridge, the longest suspension bridge in the world with a rail system of 3 meters in length.
The Chamber of Civil Engineers (İMO) Bursa Branch organized a technical trip to the 408rd Bosphorus Bridge, the longest suspension bridge in the world with a rail system of 3 meters in length.
Transferring the technical features of the bridge in terms of civil engineering, the 1st Regional Directorate of Highways Suspension Bridge Chief Civil Engineer Cevat Alim said that the 3rd Bosphorus Bridge is a hybrid bridge designed with a mixture of suspended and inclined suspension bridges and will be the first bridge to be built in this size in the world. “Our cables have 100 years of durability and no changes are expected due to fatigue. We have 7 suspension ropes and 68 curved suspension cables, which are formed by combining different number of wires with a diameter of 176 millimeters. A cable twist will occur with 52 wires of 7 millimeters in diameter. When 65 and 151 of these come together, the bent hanger will form the cable. For the first time in the world, such a cable is used. You need over 4 tons of power to break a small wire inside. ” said.
Members of the İMO Bursa Branch examined the bridge legs in the Garipçe Village of the 59rd Bosphorus Bridge, which is the largest suspension bridge in the world with a width of 329 meters and 3 meters above sea level. The members of İMO Bursa Branch received detailed information about the project with the presentation of Cevat Alim, Civil Engineer of Highways 1st Regional Directorate Suspension Bridge, on the Northern Marmara Motorway and the 3rd Bosphorus Bridge. Alim said that the bridge is an exemplary project for the world with its 15 kilometers highway and connection road, 2 lane train road, 8 lane highway capacity and aesthetics. Noting that the bridge will carry passengers from Edirne to Izmit with the rail system that will pass over it, Alim said that the project carried out with the partnership of IC İçtaş-Astaldi-Chodai and Yüksel Proje continues rapidly.
Explaining that he was given to the IC company with a build-operate-transfer model for 10 years, 2 months and 20 days including the construction phase, Alim said: “The most important feature of the bridge, which is 408 meters long, is the design of the carrier system. Long span bridges are divided into suspension bridges and bent suspension bridges. Our 1st and 2nd Bosphorus Bridges are designed as suspension bridges. The Metro Pass Bridge on the Golden Horn is a bent suspension bridge. The 3rd Bosphorus Bridge will be a mixture of these two bridges. It is called a hybrid bridge. It was built as a high rigidity suspension bridge. This mixture was applied as both high-speed train and freight train will pass over the bridge. Suspension bridges behave quite elastic under moving loads and major deformations are experienced. If we made a classic suspension bridge, we could face big displacement and deformations during freight train passes. In order to reduce these displacements and deformations, hybrid bridge design with increased rigidity was made. This is a unique design and will be a hybrid bridge to be built for the first time in this diameter in the world. 3 Bosphorus Bridge and Izmit Bay Crossing the bridge into the top 10 in the world when completed will include two bridges from Turkey. "
MİCHEL VİRLOGEUX BRINGS NEW INNOVATIONS
Alim said that one-day operating loss for the bridge will be 2 million dollars, and emphasized that the 95-kilometer highway and bridge toll will be $ 11 in total. Dr. designed the bridge. Stating that Michel Virlogeux brought new innovations to the bridge, Alim explained these systems as follows: “The unbalanced cable suspension bridge system is one of the innovations brought by Michel Virlogeux to the bridge. Our main opening and deck are steel. Our side opening is reinforced concrete. Our main span is 408 meters. Our length from the anchor block to the anchor block is 2 thousand 164 meters. We have 22 main spans, 22 main spans. Our bridge has a special situation. 17 cables connected to the reinforced concrete top and the main opening. These are balancing each other. But our last 5 cables on the side opening are connected to the rigid approach plate. Thus, he transfers the force on the ground. The 5 cables, which cannot be balanced in the main opening, keep the table in constant tension. The rope makes it tense like the tightrope of the walker. In this way, the rigidity of the deck is increased by one more step. Since the forces required by the 5 cables cannot be transferred to the tower area, the pressure in the tower area decreases. The decrease in pressure prevents the reinforced concrete sections from being crushed and the steel sections from being buckled. ”
4 TONE FOR NEED A WINE
Speaking about the cable features of the bridge, Alim said: “Our cables have 100 years of durability and no changes are expected due to fatigue. We have 3 main cables. 5.4 wires of 127 millimeters in diameter on the main cable will combine a cable strand. When twisted 113 in the main opening and 122 twists in the side opening will form another main cable. We have 7 suspension ropes and 68 curved suspension cables, which are formed by combining different number of wires with a diameter of 176 millimeters. A cable twist will occur with 52 wires of 7 millimeters in diameter. When 65 and 151 of these come together, the bent hanger will form the cable. For the first time in the world, such a cable is used. You need over 4 tons of power to break a small wire inside. If we add all the wires end to end, we will have covered 124 thousand 832 kilometers. This means traveling around the world 3 times. The cables have a real tensile strength. There is also a thousand 960 megapascal resistance guaranteed by the company. This fact is 5 percent below strength. When calculations are made according to the most unfavorable conditions, cables operate with 45 percent capacity. But the cables are calculated twice as safely. A freight train is 3 tons, and the 200rd Bosphorus Bridge was built considering that two freight trains could pass at the same time. ”
THE WRAPPING FACTOR WITH THE MOST TIME
Noting that the concrete strength of the bridge is C50, Cevat Alim emphasized that the compressive strength is 70 megapascals in the tests. Pointing out that the earthquake factor is not the main factor in the design of the 3rd Bosphorus Bridge, Alim said, “Our most important factor is the wind. The bridge is in an area where strong winds blow. Wind was the most time-consuming during the application. We were not able to shoot the cables during the periods when strong winds blow. The highest wind speed recorded in Istanbul in the last 40 years is 130 kilometers per hour. The bridge has a power that can withstand 170 kilometers of wind per hour. ” said.