• Six-lane suspension bridge extends three kilometers across the Sea of Marmara
• About 390 sensors monitor structural health
• Suspension bridge cuts travel time in half

Following a construction period lasting 42 months, Turkey's new Osman Gazi Bridge has now opened and can carry more than 40,000 vehicles every day. Working on behalf of Japanese construction company IHI, Siemens took the role of electro and mechanical contractor with responsibility for the development, installation and commissioning of all the bridge structure and traffic control components and systems. The six-lane bridge with separated maintenance lines is part of a freeway project linking the cities of Istanbul and İzmir in Western Turkey.

Constructed entirely from steel and with a main span of 1550 meters, the bridge is suspended 64 meters above the Sea of Marmara to the south of Istanbul - a region which is considered particularly prone to earthquakes. The structure therefore had to be fitted with special technology that continuously measures vibrations, movements and loads to give alarms to the bridge operators for all abnormal events.

Siemens has equipped the bridge with about 390 sensors that constantly monitor its condition and raise the alarm in the event of excessive vibration. The sensors continuously measure longitudinal and lateral strain as well as the stress loads on the road sections leading up to the main span. Special GPS sensors fitted to the bridge register oscillations of the bridge piles down to the last millimeter, while wind and temperature measuring units are also provided.

Changes and potential damage to the bridge are also immediately detected by the sensors, for instance to check the steel structure continuously for corrosion. In the interior chambers of the bridge, in the bridge towers and bridge decks as well as on the sheathed suspension cables, a special system controls and regulates atmospheric humidity, ensuring it remains below 40 percent to prevent the steel from rusting in the sea air.

The construction of the bridge and the 420-kilometer-long highway between Istanbul and İzmir is part of the largest freeway project in Turkey to date. The Concessionaire Otoyol Yatirim ve Isletme A.S. (Nurol-Özaltin-Maykol-Astaldi-Yüksel-Göcay) has been appointed under the terms of Built-Operate-Transfer (BOT) contract to plan and operate the new motorway over a period of 22 years. This new six-lane bridge connection will cut the travel time between both cities from eight to three hours.

This press release and press pictures are available at www.siemens.com/press/hightech-suspension-bridge