World’s Longest Suspension Bridge Opens
Turkey’s 1915 Çanakkale Bridge, the world’s longest midspan suspension bridge, is expected to host an official ceremony this week after opening to traffic on Feb. 26. The 2,023-meter (6,637- foot) span, which crosses the Çanakkale (Dardanelles) Strait, will reportedly cut travel time between Asia and Europe down to just six minutes.
Expected to be attended by Turkey’s President Recep Tayyip Erdoan, the ceremony is slated to take place on March 18. The date coincides with the 107th anniversary of the bridge’s namesake, the Çanakkale Naval Victory in World War I.
Prior to bridge construction, travel time between the two continents typically took about 30 minutes via ferry, but was subject to weather delays and hours of waiting in line during holiday seasons. A reduction in ferry traffic is expected due to the bridge’s completion.
The project reportedly cost a total of 3.1 billion euros ($3.41 billion), 100 million euros more than originally anticipated due to the effects of the COVID-19 pandemic and inflation in prices.
In mid-February, officials told reporters that the bridge was 99% complete. The remaining work needed done included final groundworks and asphalting, which were completed later that month.
Minister of Transport and Infrastructure Adil Karaismailoglu stated that there are only a few days left for the opening of the 1915 Canakkale Bridge and Malkara-Canakkale Highway, and that the project, which will reduce the transit time to 6 minutes,https://t.co/LxhiIORIne
— Türkiye News (@turkiyenewsen) March 15, 2022
The structure will connect to the Malkara-Çanakkale Highway and play a critical part of the 101-kilometer (62.75-mile) route. Additionally, the project is expected to ensure the integration of the ports in the Marmara and Aegean regions into all transportation systems.
In total, including the 2,023-meter span, the bridge reaches a length of 4,609 meters (15,118 feet). The bridge, with a toll of 15 euros ($16.54), is expecting to see 45,000 vehicles daily.
Project Background
In 2017, it was announced that Turkey was moving forward with plans to build what would become the world’s longest suspension bridge, to be built by a consortium of South Korean and Turkish companies in the city of Çanakkale.
At the time of the announcement, the 1915 Çanakkale Bridge was expected to be built over the next five-and-a-half years and have the longest main span of any suspension bridge in the world, at just over 2 kilometers, surpassing the Akashi-Kaikyo Bridge, in Japan, by about 32 meters.
Turkish officials held a ceremonial signing in Ankara on March 16 with representatives of the consortium of contractors selected for the job: South Korea’s SK E&C, Daelim and Limak, and Turkey’s Yapi Merkezi OGG.
The bridge was expected to cost about $2.8 billion to build, the Turkish government said, and will connect Çanakkale with the national park area commemorating the WWI fighting at Gallipoli, where 500,000 soldiers lost their lives. The bridge, across the Dardanelles, will be about 200 kilometers (125 miles) southwest of Istanbul.
The Çanakkale 1915 was designed by Tekfen Holding after that firm was awarded the design contract in 2012. Its design takes into account seismic stability, as Turkey is particularly vulnerable to earthquakes, being situated on the North Anatolian Fault.
According to Engineering News-Record, high winds, high seismic activity and high-stacked container ships all had to be considered in the bridge design, said Henrik Andersen, Senior Director for International Bridge Projects with COWI, which led detailed design.
“The bridge is located at the southern entrance to the Marmara Sea towards Istanbul and the only route toward the Black Sea in the North—very large container ships and cruise ships will pass in the future and the risk of ship impact is considered in the design,” he said. “Today, more than 40,000 vessels pass every year, and that is expected to increase significantly in the 100-year bridge design life.”
The bridge was reportedly being built via the build-operate-transfer model, in which private companies are contracted to build a structure and operate it for a set period of time, using profits from tolls or other revenues to recoup costs incurred in building and maintaining the structure. Turkish officials said 12 financial institutions have stepped in to help finance the bridge. The contract will reportedly involve the transfer of the bridge back to the government in 16 to 18 years.
The goal was to finish the bridge before 2023, the 100th anniversary of the founding of the modern state of Turkey. Construction kicked off in 2018 with the laying of the towers’ foundations.
The dry dock, located on the European side, reportedly required 1,328 pilings as deep as 21 meters (about 69 feet) deep. The tower foundations, with a cellular base structure design, composed of reinforced concrete slabs and walls.
The tower consists of 128 prefabricated block segments, each weighing about 300 tons. Lower blocks were placed on a floating barge crane, while the upper blocks were placed via tower crane. To place the suspension cables, the crews had to reportedly build a pair of 4,270-meter-long (14,009-feet-long) catwalks from the tower tops.
The bridge utilizes a prefabricated parallel wire strand system, which consists of high-tensile strength wires bundled into a hexagonal shape. According to ENR, 127 wires that are 5.75 millimeters in diameter are in each bundle, with the main span using 144 bundles per side and the side spans using 148 bundles.
The construction of the bridge’s two towers, painted red and white to match the Turkish flag, was completed in 2020. The spires reach a heigh of 318 meters (1,043 feet) and were designed to symbolize artillery shells as a tribute to the legendary World War I Battle of Gallipoli.
To install these last tower blocks, contracting crews utilized cranes with a 300-ton lifting capacity, placing the blocks in the highest position in reportedly just 30 minutes.
The final deck slab was assembled in November last year. The bridge deck reaches 72 meters high and 45 meters wide with a maximum thickness of 3.5 meters. The deck carries six lanes (three in each direction) of motorway, with two walkways on each side for maintenance.
The orthotropic steel deck reportedly consists of 153 segments in total, with crews able to place up to four deck segments a day. Designed to ensure aerodynamic stability of the deck in very strong wind, the deck comprises two stiffened closed steel box girders spaced 9 meters apart, connected by 3-meter-wide cross-girders every 24 meters.
Andersen added that the bridge “built on the tradition of modern suspension bridges like the Great Belt suspension bridge in Denmark and the Ozman Gazi suspension bridge in Turkey. With its 2,023-meter main span, the Çanakkale Bridge pushes the boundaries of engineering to new dimensions.”
