What construction works are pending for the LNG Jetty?
The works for the LNG Jetty can be roughly divided into four areas:
- Deep Foundation Work
- Concrete Work
- Steelwork
- Fixtures
What does the foundation work entail?
During the foundation work, the foundation for the construction site will be built. This is defined as the transition portion from inside the ground towards the building itself. For the LNG Jetty, this means that various posts (so-called piles) are driven into the ground. This includes pile-driving work using larger piles (roughly between 71 and 210 cm in diameter), as well as the deployment of micro piles. Micro piles are piles with a small diameter. They serve to take on and deflect some of the tensile and pressure forces, thus stabilizing the construction as a whole. In the case of the LNG Jetty, these micro piles consist of a combination of an outer diagonal pile, and an inner centering pipe, plus an anchoring system.
What does the concrete work entail?
The concrete work represents the crucial part of the jetty. The platform and the access gangways of the jetty are manufactured from concrete. This includes semi-finished parts made from concrete. These are thin concrete shells that are pre-constructed and are later on applied to the construction site in a targeted manner. All told, nine semi-finished parts will be needed and deployed. These are poured/manufactured in Emden. Afterwards, the parts are loaded onto a pontoon and towed by tug boat to Wilhelmshaven. The weight of each part is roughly between 160 and 380 metric tons.
In addition, local concrete is required, i.e. concrete that is mixed and poured on site, where it will cure. This is done for multiple concrete sections in a row, requiring some 3,000 m³ of this construction material.
What does steelwork entail?
The mooring and docking piles (so-called ‘dolphins’) are connected via access paths (stays) with the platform. These stays are manufactured from steel. The stays measure some 350 meters in length and consist of 18 individual gang stays.
What do the fixtures entail?
The fixtures ensure the fastening (attachment) of the FSRUs (Floating Storage and Regasification Units). In order to attach these, slip hooks (hooks with a flap mechanism) are mounted onto the mooring dolphins. They are designed to bear a weight of up to 150 metric tons.
What has happened so far?
141 out of a total of 194 piles (foundation piles/diagonal piles and ice deflectors) were driven into the ground. Eight micro piles were completed. The concrete platform and the access bridge were successfully installed on August 31 and September 1 with the help of floating crane “Enak” (see image, photo owner: NPorts).
What are the next steps?
The pile-driving activities for the remaining 53 piles are the next step in realizing the specifications of the construction plan. Three additional semi-finished parts made from concrete have already been manufactured and are currently en route to the construction site. There are four more semi-finished parts that still need to be manufactured and installed. Concrete work using local concrete on site has recently commenced and will continue until the end of construction.
What could delay the progress of construction?
Construction work is on target at this point. However, delays due to external factors cannot be excluded. This includes influence by weather, as it may occur in connection with the upcoming flood water and storm season.
At the moment, supply chain bottlenecks in regard to the required parts are not likely to occur, since all the crucial materials are already on site.
Credit for photos on site: Andreas Burmann
Aerial images: Wolfhard Scheer
