Water Bridge in Germany

Even after you see it, it is still hard to believe ! Water Bridge in Germany.... What a feat! Six years, 500 million euros, 918 meters long.......now this is engineering! This is a channel-bridge over the River Elbe and joins the former East and West Germany, as part of the unification project. It is located in the city of Magdeburg, near Berlin.

The photo was taken on the day of inauguration. To those who appreciate engineering projects, here's a puzzle for you armchair engineers and physicists. Did that bridge have to be designed
to withstand the additional weight of ship and barge traffic, or just the weight of the water?

Answer:

It only needs to be designed to withstand the weight of the water!
Why? A ship always displaces an amount of water that weighs the
same as the ship, regardless of how heavily a ship may be loaded.

This is from Wikipedia:

The 918-metre Magdeburg Water Bridge or Wasserstrassenkreuz in German, (52.231, 11.701), completed in October 2003, connects two important German shipping canals, the Elbe-Havel Canal and the Mittellandkanal, which leads to the country’s industrial Ruhr Valley heartland. Engineers first conceived of joining the two waterways as far back as 1919 and by 1938 (longer ago than the Beach redevelopment idea!) the Rothensee lock and bridge anchors were in place but construction was postponed during the first and second world wars. After the Cold War split Germany, the project was put on hold indefinitely by the East German government. With the reunification of Germany and the following establishment of major projects in transport tracks the Water Bridge again became a priority. Construction began in 1997 and after six years and around half a billion euros the gigantic water bridge now connects Berlin’s inland harbour with the ports along the Rhine river. The huge tub created to transport ships over the Elbe took 24,000 metric tons of steel and 68,000 cubic meters of concrete to build. Until the opening of the water bridge in October 2003 the ships moving between the Midland canal and the Elbe-Havel canal had to detour 12 km through the Rothensee lock, the Elbe and the Niegripp lock.

Below is an aerial of the area. The water bridge is the northern one. You can see a traditional highway bridge to the south: