Bridge over the Enns river, in Austria

Abstract

A road bridge has been recently opened over the Enns river at Steyr (Austria). The purpose is to improve traffic and avoid the bottlenecks that often took place. The bridge is supplemented by three other works of lesser importance, namely two bridges and a tunnel for pedestrians. The bridge structure supporting the decks is cellular, box type. It has three compartments, and four vertical partitions, whose thickness varies from 6 m over the intermediate piles to 2.30 m at the crown. There are three spans, of 47, 101 and 70 m length. The bridge intrados forms a smooth curve. Two overhangs extend from the central structure, and provide sidewalks for pedestrians: the deck itself having a width of 17 m. The structure was made in successive overhangs, in 3.50 m sections. Longitudinal prestressing, by means of PZ-A-100 type cables, was done by applying an initial loading of 120 t. The cables run in tubes. After the concrete had reached a suitable strength, the cables were stretched. The tubes were then filled with cement mortar, and in this operation air suction equipment was utilised to make sure that no air cavities were left.