terra infrastructure contributes 3,500 tons of sheet piles

The ETL 180 natural gas transport pipeline has a length of 55 km and provides the linkage between the LNG terminal in Brunsbüttel's Elbehafen port and the feed-in point to the transmission network in the Hetlingen area (Pinneberg district). Together with the approximately three-kilometer-long ETL 185 pipeline section – connecting Brunsbüttel to the electricity and gas network in Schleswig-Holstein and northern Lower Saxony – the total project volume amounted to around €120 million. But these were not the only impressive figures associated with the project. In addition to a relatively short construction period of around one year, the demanding soil conditions, which were predominantly clay, posed a challenge. This meant that the trench for the DN 800 pipeline pipes had to be secured in sections with Sheet piles. With the delivery of approximately 3,500 tons of tkL 603 k sheet piles and numerous corner sections, terra infrastructure helped to overcome the logistical challenge.

Gas-based power supply has undergone a breathtaking transformation in recent years. In particular, the failure of imports from Russia and the search for suitable replacements necessitated measures and changes in a very short time that would previously have taken decades. Based on the LNG Acceleration Act passed in May 2022, the construction and initiation / commissioning of LNG terminals and the associated infrastructure demonstrated that it is possible to respond quickly to impending shortages. This also applies to the liquefied natural gas terminal in Brunsbüttel, which went into regular operation in April 2023. In a second step, natural gas transport pipelines were built to reliably connect LNG imports to the German and European gas infrastructure. In order to be able to continue to perform transport tasks in a CO2-neutral economy in the future, the pipeline's execution was designed to be “hydrogen-ready.”

To secure the pipe trench, terra infrastructure delivered around 3,500 tons of tkL 603 k sheet piles to the site. “These are classic hot-rolled U-profiles, which are mainly used for securing excavation pits or as abutments for trenchless crossings – including 19 pressings and 11 pipe layings using the horizontal directional drilling (HDD) method,” explains Dipl.-Ing. Robert Haupt, Deputy Head of Sales Germany, terra infrastructure GmbH. The hot-rolled profiles are made from a raw material that is heated to over 1,200 degrees Celsius. The high plasticity of the steel allows for different profile shapes, such as U-profiles. “These have excellent static properties,” Haupt continues. “Among other things, they are characterized by high installation performance. Due to their optimal reusability, they can be recovered after use and reused.”

The ground conditions in particular meant that the trench for the pipes could not be secured using a conventional shoring system, but had to be secured in sections using Sheet piles. In this respect, the profiles scored highly thanks to their properties. For example, they can be loaded immediately, are flexible in length, can be used in water, and have an extremely favorable ratio of steel cross-section to moment of resistance. In addition, the use of the profiles ensured rapid construction progress. According to Haupt, the logistical task was mastered without any problems – and in a very short time. The approximately 2,200 profiles, each with a length of 12 meters, were delivered to the installation site between the end of February and the beginning of April 2023. “On average, 20 to 25 trucks drove to the site each week,” recalls Haupt. In addition to the profiles, numerous corner sections were also delivered. In total, approximately eight kilometers of pipe trench were provided with additional sheet piling on one or both sides. The sections of the trench ranged from 10 m on both sides to approximately 400 m on both sides and were distributed over the 54 km long route, of which approximately 45 km are laid in open pipe trenches.

terra infrastructure was involved in the construction of the 55 km long natural gas pipeline from Brunsbüttel's Elbe port to the feed-in point in the transmission network in the Hetlingen area (Pinneberg district), supplying approximately 3,500 tons of tkL 603 k sheet piles and numerous corner sections.

The sheet piles are classic hot-rolled U-profiles, which are mainly used for securing excavation pits or as abutments for trenchless crossings.

The tkL 603 k sheet piles are characterized by their high installation performance, among other things. Due to their optimal reusability, they can be recovered after use and reused.

Critical soil conditions in particular meant that the trench for the pipeline had to be secured with sheet piles in sections rather than with a conventional shoring system.