THE CHALLENGE
More often than not the rehabilitation of existing structures is a more complex endeavor than new developments. This is particularly true for listed buildings. In the case of the St. Pauli Elbe Tunnel, space restrictions called for tailored solutions. Contractor “ARGE Zueblin und H.C. Hagemann” was looking for a reliable system to drain off occurring seepage water, one that would endure the shotcreting process without concrete getting into the drainage core, also a frictional connection between the new lining and the existing construction was to be avoided.
THE ENKA SOLUTION
Installation of EnkaDrain CK20:
EnkaDrain CK20 is a multifunctional geocomposite for drainage and lost shuttering/ sealing. Its three-dimensional polyamide monofilament core is attached to a water permeable nonwoven filter on one side and a concrete or shotcrete tight PVC layer on the other.
With a discharge capacity of up to 3.2 l/sm the product met and exceeded the seepage water drainage requirements calculated for this project.
Thanks to its specific properties the drainage core remains flexible even when under pressure. This meant that the composite could be used to prevent friction between the new liner and the existing construction.
Facing inwards, the product’s PVC fabric allows the composite to serve as a sealing. As with most other projects also at the St. Pauli Elbe tunnel the PVC fabric overlaps were welded so that no concrete slurry could enter the drainage core during the shotcreting process.
To master the prevailing space limitations, EnkaDrain CK20 was supplied pre-cut. Also, material was delivered to the site almost “just in time” making stocking of larger quantities redundant.
INSTALLATION BENEFITS & RESULTS
Proven performance no doubt is one of the biggest advantages of EnkaDrain CK20. For many years now the product has been used in numerous rehabilitation projects.
Installation of the composite is fast and easy. The product can be fixed on any subsurface. Pre-cutting to length as well as the supply of material only shortly before installation were amongst the benefits supporting the specification of EnkaDrain CK20 for the St. Pauli Elbe Tunnel project.