Exceptional challenges require special solutions. We are known for unique new construction methods and ideas - if necessary we do not use standard solutions, but combine different techniques, make new inventions (as our patents prove) and develop tailor-made special solutions.
Example: Protection shield for the Elbe tunnel
The fairway of the Elbe was deepened more and more. To prevent dragging anchors from damaging the Elbe tunnel, a protective structure had to be built for the Elbe tunnel. The construction work in this special, sensitive environment required extreme precision. To secure the Elbe tunnel, 6 m long sheet piling was installed on both sides of the lowered tunnel elements. Between the sheet pile walls projecting approx. 1.50 m above the upper edge of the tunnel, an 80 cm thick protective layer of metallurgical slag was placed, which was still clamped with Colcrete mortar. Technical management Bilfinger Construction GmbH, Partner Heinrich Hirdes GmbH - Client: Free and Hanseatic City of Hamburg.
Challenge: During the entire construction period, shipping traffic in the area of the New Elbe Tunnel had to be maintained without disruption at all times.
20 meters depth, 0.20 meters visibility, 3 knots flow velocity - the tolerance for threading in the sheet piles is max. 2 cm. Working only possible in daylight. At night, the jack-up platform must leave the construction site and find the exact position where the last screed was driven under water the next day!
Solution: Work from a jack-up platform - a fixed platform that stands still and is not exposed to waves, currents and the tidal range. On the island: ramming excavator that brings in the sheet piles under water, guided by a leader.
To find the exact position a DGPS equipment with inclinometer was installed on the leader and software was used which was specially developed for this construction site. Satellite technology is used in the search for the original driving point. The pile driving of the sheet piles is coordinated by DGPS (Differential Global Positioning). A variant of satellite navigation in which several satellites and a reference transmitter on land are used for exact positioning.