Istanbul Strait Road Tube Crossing: Challenges, Risks and Mitigation Strategies

Synopsis:

The 13.2 m external diameter double deck Istanbul Strait Road Tube Crossing is one of the most challenging underwater tunnel projects in the world. Subjected to 11 bars of hydrostatic pressure, variable geology, and being in a very active seismic area, the execution of the project required innovative solutions, sophisticated construction techniques, and prudent risk management approach. The 5 km tunnel consists of 3.4 km TBM bored tunnel, 1 km twin NATM tunnels, and cut and cover sections. The project is being delivered in a Build-Operate-Transfer (BOT) contract in a public-private partnership. The technical challenges, coupled with financial and commercial risks required the implementation of sophisticated risk management tactics including the provision of Independent Design Verification. Presently, the project is in its advanced stages of construction with a recent successful TBM breakthrough on August 22nd 2015. The paper presents the technical challenges of the project from the design, construction, and risk management aspects and provides the status of the construction.

2016 World Tunnel Congress and 42nd ITA General Assembly Proceedings
April 22-28, 2016, San Francisco, CA (Munfah, N., Clark, G., Arioglu, B., Zlatanic, S., Togan, T.)
Copyright holds the International Tunnelling and Underground Space Association (ITA).