Istanbul Golden Horn (Halic) – Immersed Tube Design

Istanbul, Golden Horn


Istanbul Metropolitan Municipality

Arcadis Nederland BV Branch Ankara

Features / Capacity / Area
900 m long 3×2 bridge and shore structures

Contract Date
2015 August

It is a feasibility study and conceptual project developed to connect the two sides of the Golden Horn in Istanbul with an immersed bridge, in partnership with ARCADIS NV. Instead of the existing Unkapani Bridge over the Golden Horn, it is envisioned to design and construct an immersed tube tunnel with three lanes in each direction to serve as a main arterial road connecting the two shores.


The design is carried out in compliance with specifications and regulations set by the authorities, utilizing methods suggested and developed by the contractor. The tunnel is submerged underwater, ensuring it does not disrupt the historical silhouette of the area and is designed to avoid interfering with maritime traffic on the water surface and water flow within the sea. For maritime traffic, a draft depth of at least 8.50 meters and a 100-meter maritime vehicle transition zone are provided.


Two structures are designed at the shores of the Fatih and Beyoğlu districts of Istanbul. The structure is designed to be resistant to corrosion, salt, and other similar factors (physical, chemical, and biological) that may be encountered due to its underwater location. The structure constructed in line with advance technology and shall be conformed to the following standards.

  • Turkish Standards
  • EU Standards (EN)
  • IEC Standards
  • DIN Standards
  • ISO Standards

When this project is realized, the existing old bridge will also be removed. However, the project has been frozen for now due to its cost. Prota provided geotechnical and structural (RC and steel) design.

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