Rotterdam, Netherlands: DYWIDAG Strand Anchors stabilize Europe’s largest Harbor
With a total area of 105km², Rotterdam Harbor in the Netherlands is Europe’s largest port. The harbor consists of several port areas extending from Rotterdam city center to the North Sea along a distance of 40km.
In order to maintain the harbor’s leading position in the future, construction work started at Maasvlakte 2 in September 2008. Maasvlakte 2 is the western extension of the harbor in the North Sea, which is being constructed by reclaiming land through spraying on sand. The new terminal will also include a 1.15km long deep sea quay with water depths of up to 20m, which will make Rotterdam the only harbor in Europe able to accommodate container ships of the newest generation.
The front wall of the new feeder quay wall is constructed as “combi wall” using Ø 1.2m steel piles and sheet piles. A 3.25 x 7m large concrete sleeve is positioned on top of the combi wall.
DSI assisted with the design of the sheet pile wall and supplied and installed the DYWIDAG Strand Anchors that were needed for horizontally tying back the quay wall. The unbonded DYWIDAG Strand Anchors consist of 20 greased and HDPE coated 0.62" strands equipped with two MA 6822 anchorages with helices and protection caps to prevent the ingress of sea water.
Inside the concrete sleeve of the quay wall, the HDPE trumpets of the DYWIDAG Strand Tendons are connected to a Ø 140mm HDPE tube. In the transition from anchor length to free length, the HDPE duct is protected by an extra Ø 160mm HDPE tube. Special curved deviator saddles are used to prevent sharp bending and damage to the strand tendons in case of soil settlements of the reclaimed sand behind the front wall.
In total, 360 strand tendons were installed in the 1.15km long deep sea quay wall at distances of 3.1m.
Depending on the soil quality, the DYWIDAG Strand Anchors are between 40 and 45m long. The anchors were tensioned in two steps to 50% and 100% of their tension force and injected with cement grout afterwards.
Due to their flexibility, their ease of handling and long service life, the horizontal strand anchors proved to be the optimum solution for the quay wall of the new container terminal. In addition, the tendon length can be adapted to suit on site requirements, and the tendons can be tensioned to accurately defined forces. Even if the quay wall were to deform at sometime in the future, the DYWIDAG Strand Anchors can be restressed.