Widening of the Oberkassel Bridge
Soon after the turn of the century, it became clear that the Oberkassel Bridge would not be able to cope with the growing volume of traffic in the long term. This led to the commencement of planning in around 1912 for the conversion of the Oberkassel Bridge, though the plans had to be shelved when the First World War broke out. After the war and shortly before the end of the Rhineland occupation, planning recommenced. Some difficulties were encountered because the planners had to negotiate the widening of the bridge with the French, since it was under the command and control of the French occupying power between 17 th September 1924 and 17 th August 1925. The French imposed various conditions to ensure the safety of its troops.
When these conditions had been recognised, the bridge conversion project was awarded to Philipp Holzmann und Co., Gutehoffnungshuette and Hein and Lehmann & Co. Work commenced on 11 th March 1925 and ended on 20 th April 1926. The conversion was approved by the river building authority, subject to the proviso that the scaffolding was removed from the water by 15 th December 1925. However, ice on the river made it impossible to remove enough of the scaffolding before 22 nd December to prevent the new bridge construction being endangered by the ice and high water. The water level reached 9.10 m that year, which was the highest level recorded since 1784.
When the bridge arches were built, the engineers made sure that they did not impair the overall aesthetic appeal of the bridge to any great extent. Although the cycle path between the original arches and the reinforcement arches was slightly too narrow at 1.20 m, this could not be altered. On the other hand, the bridge design ensured that the general traffic, especially vehicle traffic, did not interfere with the rail traffic. The Rheinbahn’s trains were now able to ‘zoom’ across the bridge at top speed on their own track and pedestrians had a wider pavement.