July 2014
Strait Road Crossing: a new Bosporus Crossing for Istanbul
Istanbul, the largest city in Turkey, is a huge metropolitan area with 14 million people. As a city that spans two continents, it is intersected by the Bosporus, the strait that connects the Mediterranean Sea with the Black Sea.
In addition to a ferry service, a big part of daily commuter traffic utilizes the few bridges that span the Bosporus. Istanbul and it’s population lives with daily traffic congestion. The Marmaray subway tunnel has already been built under the Bosporus. With the beginning of the Strait Road Crossing project a big part of the intercontinental car traffic is to be diverted under the sea.
The construction of the tunnel fits into the larger project of the modernizing of the Istanbul highway network. A consortium of Turkish and South Korean construction companies (Yapi Merkezi and SK Engineering) are responsible for the construction of the tunnel in a public-private partnership.
Using a 14 m diameter Herrenknecht tunnel boring machine will bore its way through the planned 3.35km long tunnel which, at time will lay up to 80m below the sea bed. Once complete the tunnel will be split level, providing one level for each direction of travel.
VMT system technology helps the project contractors to deliver the high quality standards and precision that comes along with this huge project:
In the segment production, which the Turkish firm Yapi Merkezi is responsible for, the VMT segment documentation system, SDS, helps the engineers in the supply management and quality management of all segments for the tunnel lining.
The VMT laser-controlled Tunis navigation system the tunnel boring machine can be guided with millimeter accuracy along the intended designed path. With accurate input of VMT GAPtrix system the TUnIS ring sequencing is supported in the calculation of rings to be constructed. The ring sequencing in connection to the aboveground installed SDS on the construction site supports the planning and logistics of transporting the needed ring segments to the tunnel.
The TUnIS ring planarity check which is connected to the ring sequencing controls every ring on compliance of necessary flatness to prevent spilling form point loads.
The continuous process control of the relevant TBM data is made possible via the ubiquitous web-based Risk and Information System, IRIS. IRIS allows the project management to get a detailed view of the progress of the project via the automated logging of data, allowing the improve performance the shift and machine connected to the planning of maintenance jobs.
This project be using the following VMT systems:
- Segment Documentation System SDS monitors and documents all production steps of a segment, from the concreting to installation in the tunnel
- TUnIS Navigation TBMLasernavigates the TBM along the planned tunnel axis
- Semi-automatic Tailskin Clearance Measurement System GAPtrix detected the tailskin clearance of the last build ring to determines its exactly position
- TUnIS Ring Sequencing calculates the ideal ring sequence and positioning
- Integrated Risk and Information System IRISpowered by ITC takes care of the process data management of completed construction section
- TUnIS ring planarity check warns the user automatically when a bump is detected on the ring