Osman Gazi Bridge
The Osmangazi Bridge is a suspension bridge spanning the Gulf of İzmit at its narrowest point,. The bridge links the Turkish city of Gebze to the Yalova Province and carries the O-5 motorway across the gulf. The bridge was opened on 1 July 2016 and surpassed the Fatih Sultan Mehmet Bridge to become the longest bridge in Turkey and the sixth-longest suspension bridge in the world by the length of its central span.
The length of the bridge is expected to be surpassed by the Çanakkale 1915 Bridge, which is currently under construction across the Dardanelles strait.
Project
Construction and operation of the bridge was awarded to a joint venture formed by five Turkish companies and one Italian construction company Astaldi following the international Build–operate–transfer tender that took place in April 2009. In 2010, a contract was signed for the project that was estimated to cost ₺11 billion for the entire highway from Gebze to Bursa.On 30 March 2013 Prime minister Recep Tayyip Erdoğan laid the ground stone for the bridge.
After the completion of the bridge, the distance between Istanbul and İzmir shortened by about, bypassing the long-stretched Gulf of İzmit. The highway and bridge reduced the travel time between the two major cities from six-and-half hours to three-and-half hours. The bridge and the connecting highway provide three lanes of traffic in each direction. The construction was completed on 30 June 2016.
EPC Bridge Contractor
The US$1 billion privately financed bridge was awarded to the Japanese firm IHI Infrastructure System Co. on 16 July 2011 as EPC basis with FIDIC Silverbook contract. IHI, which was one of the contractors of second Bosphorus bridge, also completed the seismic reinforcement projects for Halic and Mecidiyekoy viaducts. IHI subcontracted the design works to Danish engineering design firm COWI A/S, which collaborated for the aesthetic design with Dissing+Weitling. Notice to proceed was given by NOMAYG JV to IHI on 1 January 2013 and the expected total project duration was 37 months.The dimensions are:
- main span length:
- side spans length:
- clearance:
- tower height:
- tower size :
- deck size:
The bridge is fourth longest suspension bridge in the world.
Accident at construction site
On 21 March 2015 a catwalk broke away from its bolted joint cable on the south tower during the construction at the bridge and fell into the water. Added in February 2015, the catwalk was needed to allow workers access to the other side of the bay. No one was harmed by the accident as work was interrupted at this section due to windy weather. Marine traffic to and from İzmit Bay was suspended following the accident for security reasons and resumed after recovering the cable in the morning of 23 March.Kishi Ryoichi, the 51-year-old Japanese engineer of the IHI-Itochu Consortium, who was in charge of the construction at site, committed suicide after the accident. He was found dead at the entrance of a cemetery near his lodging in Altınova. He left a note saying that "...this failure ends my private and professional life. This project was mine and my country's pride. No one else is responsible for this failure."
Tolls
As of 1 January 2019 the bridge tolls are:| Vehicle class | Toll ₺ | Toll $ |
| Vehicles with 2 axles, wheelbase <3.2m | 103 | ~18 |
| Vehicles with 2 axles, wheelbase >3.2m | 165 | ~28 |
| Vehicles with 3 axles | 196 | ~34 |
| Vehicles with 4 or 5 axles | 260 | ~45 |
| Vehicles with 6 or more axles | 328 | ~56 |
| Motorcycles | 72 | ~12 |