Turkstream Dropped Object Culverts

Our Experience


  • Year
  • Client
  • Location
    Black Sea, Turkey
  • Scope of Work
    MMA was contracted to design, engineer and fabricate ten (10) culverts to protect the pipeline from dropped objects.

Project Overview

Our client required a new pipeline system to export gas across the Black Sea consisting of:

  • Two 32” pipelines from Anapa, Russia to Kiyiköy, Turkey with a total length of 925km
  • Two micro tunnel pipeline sections on the Russian side
  • Two above water tie-ins on the Turkish side

Before it was possible to pull the pipelines into the micro tunnels, both of the pipelines on the Russian side needed to be protected from dropped objects such as anchors.

MMA's Solution

MMA was contracted to design, engineer and fabricate ten culverts to protect the pipeline end terminations from dropped objects.

We engineered the culverts in-house, with all fabrication carried out locally in Turkey close to the loadout port in Samsun to minimise transportation costs. We produced the 10 custom-designed structures in just 10 days.


  • Design and engineering allowed for a bespoke solution with careful consideration to the required dimensions, dropped object weight and soil bearing capacity.
  • Local fabrication reducing transportation costs and creating local content opportunities.

Technical Details

The dimensions of the culverts were 5m x 3.5m x 3.15m with a dry weight of 32 tonnes. The lifting points were connected with a cathodic protection system to ensure easy recovery of the culverts in a later stage.

MMA Innovation / Value Added

The culverts were specifically designed to maximise seabed bearing capacity and stability with a low centre of gravity, large footprint and optimised cross-section.

The full logistics operation was considered throughout the design process, including the dimensions for road freight and subsea deployment was in line with DNV guidelines for marine operations.

Cathodic protection was integrated within the design of the lift points to ensure their integrity for future decommissioning requirements.