Installation of the Freybrücke Bridge in Berlin, Germany
ALE has installed the Freybrücke Bridge, weighing 400t, in Berlin, Germany.
The 400t bridge deck was built on supports, about 10m from the quayside.
To allow ALE to install their skidding system, the bridge deck was jacked-up 400mm using climbing jacks. The barge, with the skidding supports, was berthed and prepared for the load-out operation of the bridge deck.
The strand jack construction, consisting of six unit beams, an anchor head and a strand jack, was installed on the arc of the bridge. Using this construction, ALE released the bridge into the separate anchor heads which allowed ALE to remove the strand jacks. The bridge deck could then be suspended in the strand wires for a couple of months. In total, there were eight constructions installed with a 70t strand jack and four constructions installed with a 500t strand jack.
The bridge deck was skidded 30m onto the barge within five hours. During the skidding operation, the barge stability was controlled using pumps with a total ballast capacity of 360 m³ per hour.
After positioning the bridge deck onto the barge, the link beams between the barge and quay were removed using an 80t crane. To ensure that the bridge deck could cross the existing bridges, the bridges were measured, the water level of the river was studied and the barge was set to maximum draught. The transport height of the bridge deck was decreased by jacking-down the bridge deck using four 150t capacity climbing jacks in order to transport the bridge deck under existing bridges with a clearance of just 100mm.
Whilst the bridge deck was being transported 1km, it was turned 180 degrees using two tugs, and the mooring lines were connected using a small tug, before positioning of the barge beneath the arc
After connecting the mooring lines, the barge was positioned beneath the arc using six winches with a total capacity of 40t and the strand jack anchors were connected. The bridge deck was lifted off the barge by strand jacks, as the barge was released and transported back to the quayside.
Whilst the bridge deck was lifted into its end position, a second team was disassembling the barge and preparing it to be transported back to the supplier.
The bridge deck was finally set down into the strand jack construction. After the installation, ALE waited until they received confirmation from the client that ALE could proceed with the removal of the strand jacks. ALE tensioned the strands for the first time, these should be tensioned separately upon client instruction to create the right curve into the bridge deck.
The client then welded the bridge deck and once the curve was checked, ALE tensioned the strands for the second time when necessary, so the pendants of the bridge could be installed. After installation of the pendants all the strand jack constructions were removed.