Extending Europe’s Energy Supply: stabilize LNG Tanks

The seaport of Sagunto, located approx. 30km north of the city of Valencia, has grown to be one of the most important Spanish ports for the importation of liquid natural gas (LNG) into Spain. In line with the political goals of the European Union, Sagunto’s LNG plant contributes significantly to the expansion and diversification of Europe’s energy supply.

The first two LNG tanks were built between 2003 and 2005. Planning and construction of the third LNG tank was begun shortly after the two first tanks had been completed. Construction work on the fourth LNG tank began in 2008 and was successfully completed in June 2011. The LNG plant in Sagunto has a capacity of approx. 600.000 m³.

All four of the tanks were constructed by the UTE Ampliación Regasagunto joint venture consisting of Cobra, Sener – Spain, Toyo Kanetsu KK – Japan and DYWIDAG International GmbH – Germany. As was the case during the construction of the previous tanks, DYWIDAG-Sistemas Constructivos (DSC) was awarded the contract for producing, supplying and installing all of the post-tensioning systems.

Each tank has a height of approx. 52m. The inner diameter measures 74m, and the wall thickness varies between 60cm and 120cm. Like the previous tanks, the fourth tank was also post-tensioned using 19-0.62" DYWIDAG Strand Tendons with Multiplane Anchorages. 12 horizontal DYWIDAG Strand Tendons were installed in the floor slab, 178 tendons were installed in the exterior wall and 18 tendons were used in the ring beam.

The bottom slab was circumferentially post-tensioned with tendons anchored in 6 buttresses rotated by 60 degrees. In the ring beam and in the outside wall, the DYWIDAG Strand Tendons were anchored in 4 buttresses placed at 90° centers. Vertical post-tensioning was accomplished by 80 U-shaped 9-0.62" DYWIDAG Strand Tendons.

This Post-Tensioning System, also known as a loop tendon system, consists of two vertical tendons that are connected by an 180° arc at their bottom ends and anchored by MA-Anchorages in the ring beam at their top ends. The 650t of DYWIDAG Strand Tendons that were supplied for the fourth tank complied with EN-14620 requirements regarding cryogenic applications.

Additionally, DSC supplied Ø 25, 28 and 32mm GEWI® Post-Tensioning Bars with accessories such as couplers and nuts for cryogenic and standard applications. The tensioning bars were used as splices in the construction joints and in the assembly access openings that had to be closed following installation.

In total, DSC supplied the following products for all four tanks:

  • 640 anchorages for DYWIDAG Strand Tendons with 9 strands, Ø 0.62"

  • 1,664 anchorages for DYWIDAG Strand Tendons with 19 strands, Ø 0.62"

  • 28,500m of Ø 80mm galvanized and corrugated duct

  • 102,332m of Ø 100mm galvanized and corrugated duct

  • 122,850m of GEWI® Bars (Ø 25, 28 and 32mm)

  • 4,240 GEWI®  Couplers

  • 8,480 GEWI® Lock Nuts

Material supply for the fourth tank started at the end of 2009, and installation work began in April 2010. The placing, tensioning and injection of all tendons – excluding those located at the assembly access openings of the tanks – was successfully completed with only two teams in less than five months.

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SAGGAS, Spain