Dolphins „Rethe flap bridge"

In order to protect the 2 abutments (flap cellar) of the new Rethe flap bridge, we were commissioned in cooperation with Implenia to install 3 doplhins as a boundary for the fairway The dolphin tubes provided by the client were prepared in the port of Hamburg to be picked up from the pontoon and placed into the drill pipe and then towed to the construction site. The dolphins were installed using the suspension-supported grab drilling method up to the bottom of the dolphin tubes at a maximum depth of - 31.0 m above sea level.

The work was carried out exclusively with floating equipment or with the jack-up platform "Annegret" as key equipment. The ground was removed from the drill pipes by ball grabs and placed in a barge for proper disposal. The work was carried out in breaks on 3 consecutive weekends in multi-shift operation without interruption of work. This was necessary due to the installation procedure and the traffic situation on land and water. At the same time the factory production and conservation of the dolphin heads including the fender panel (2.5m x 6m) took place. At a later date, these were also mounted with the jack-up platform. The remaining welding and conservation was carried out in tidal work from scaffolding accessible from land via catwalks.

Specifications / Main Quantities:
Installation 2 pcs dolphins, 65 to each, L = 41 m, Ø 1,80 m using gripper drilling method
Installation 1 pcs dolphin, 42 to, L = 35 m, Ø 1,52 m using gripper drilling method
Steel hydraulic engineering: Equipment of dolphin heads and fender panels

Buildingcosts: 1,5 € Mio.
Location: Hamburg