Re-usable modular steel bulkheadsFor the transport and immersion of elements temporary bulkheads are required to seal of the ends of an element and to enable it to float. In the Netherlands these bulkheads are traditionally made out of concrete with steel columns for support. The placing and removing of these concrete bulkheads involves a number of disadvantages. For example, the required formwork, reinforcement and pouring are time-consuming, while demolishing the concrete walls after immersion is extremely time-consuming and polluting as well (dust, noise). The demolished concrete bulkheads can, of course, not be re-used.

Mergor has developed modular steel bulkheads that can be re-used within multiple projects. The bulkheads consist of re-usable columns and panels that are built in before inundation of the Pre-cast Yard. The modular steel bulkheads can resist high forces of deeper waters during immersion. After immersion a crew can dismantle the complete bulkhead walls within days, which saves weeks in the critical path to start the finishing works of a tunnel. The dismantled panels and columns can than be deployed for the next tunnel or even within the same project. This has saved the projects a significant amount of time and money.

Mergor possesses enough the steel bulkhead panels and components to fit out several tunnel elements at the same time. The bulkheads have already successfully been deployed at the Motorway A73 tunnel in Roermond (Netherlands) and the dual-carriage-way tunnel under the Shannon in Limerick (Ireland). For the Busan project the steel modular bulkheads have proven its use even in tough conditions, where the tunnel elements with modular steel bulkheads where transported 35 km over sea and immersed to depths up to 50m.