Prater Bridge, Motorway bridge over the Danube in Vienna, Austria

The Prater Bridge is a road bridge spanning the Danube, connecting Leopoldstadt and Donaustadt with multiple vehicle lanes and separate pathways for pedestrians and cyclists. The structure accommodates heavy daily traffic while maintaining distinct routes for different modes of transport.

The Prater Bridge was built from 1967 to 1970 with six lanes. On 5 November 1969 the steel structure buckled at two points during assembly because of rapid overnight temperature swings, and the site was closed over collapse risk; welded girders restored load capacity and the bridge opened on 22 December 1970. In 1996/97 it was raised 1.8 metres for the Freudenau power station reservoir, with two southbound lanes diverted over the Donaustadtbrücke.

The bridge links two districts with distinct recreational zones and residential areas, serving as a daily crossing for people moving between different parts of the city.

The bridge experiences heavy traffic during peak hours, so crossing during quieter times offers a smoother experience. Pedestrians and cyclists should use the marked pathways and remain aware of vehicle traffic.

During assembly, rapid night-time temperature swings caused such stress that the steel structure buckled at two points on 5 November 1969; the site and the road, rail and river routes beneath it were closed over collapse risk. Welded girders bridging both buckles restored load capacity, and the bridge opened on 22 December 1970. A slight dip in the carriageway still marks the spot, and for a time locals called it the "Knickbrücke" (buckled bridge).