Immersed Tunnel Technology Scheldt Tunnel

Project description

The Scheldt Tunnel consists of eight tunnel elements, each approximately 160 metres long, constructed in Zeebrugge. Once completed, these elements are transported by water to Antwerp, where they are carefully immersed into the River Scheldt in a controlled operation.

The project is being delivered by THV COTU, a consortium of leading international contractors. Within this collaboration, MH Poly is part of the OTAO engineering team, contributing to a wide range of technical challenges related to the construction and installation of the immersed tunnel.

Our role and approach

MH Poly’s strength in this project lies in the combination of engineering design, 3D modelling and practical construction expertise. Our multidisciplinary experience in civil engineering, hydraulic engineering and industrial projects enabled us to contribute effectively throughout different disciplines and project phases.

Working closely within the team, we actively supported both design development and construction engineering. This long-term collaboration allowed us to apply our expertise in immersed tunnel technology across the full engineering process.

Engineering activities

Within the OTAO scope, MH Poly was responsible for the engineering of a wide range of components and systems, including:

Engineering of access shafts and structural components
Design of primary and secondary supports
Engineering of GINA seal protection and bulkheads
Structural calculations for steel and concrete structures, including reinforcement and welding details
Preparation of P&IDs (Piping & Instrumentation Diagrams) for ballast, sand flow and leakage water systems
Translation of engineering calculations into production drawings

In addition, MH Poly managed the complete BIM integration of the OTAO components, including:

3D modelling in Autodesk Revit
Clash detection and coordination
Parameter management within BIM 360
BIM implementation throughout all project phases: Concept Design (CD), Preliminary Design (PD), Detailed Design (DD) and Construction Design (CD)

From design to construction

MH Poly was involved not only during the design phase but also throughout construction. Our engineers provided on-site engineering support in Antwerp and developed practical solutions for technical challenges encountered during installation.

This direct connection between engineering and construction enabled efficient decision-making and ensured highly practical, buildable solutions.

MH Poly’s involvement in the Scheldt Tunnel project spans five years. The immersion of the tunnel elements in 2025 marked a major milestone in this prestigious infrastructure project.