Special feature: Construction of an excavation pit in the building pit
The excavation pit wall is constructed as a soldier pile wall and secured with internal supports and grouted anchors. Where low-deformation shoring is required to secure adjacent existing buildings, sections are constructed as bored pile walls. Empty boreholes are already used in this phase to create a deeper excavation pit, which is integrated into the groundwater and therefore sealed with an underwater concrete base and additionally secured against uplift with micropiles. In addition, the low-lying construction pit must also absorb the loads of the higher-lying shoring via inclined stiffeners, which poses a special challenge in both planning and execution.
Extensive quality control accompanies construction work
Due to the inner-city location, an explosive ordnance probe was carried out prior to the construction of the excavation pit, and the client arranged for the preservation of evidence of the condition of the building fabric adjacent to the construction site. The client was particularly concerned about reducing noise, dust and vibrations. The primary goal: to disturb the residents as little as possible. All work in the area of the adjacent buildings, gardens and streets is carried out carefully and gently (i.e. with low vibration, noise and dust) according to the current state of the art. The use of the large drilling rigs is flanked by vibration monitoring. Regular settlement measurements and height levelling serve to detect any adverse effects on neighbouring buildings in good time. In addition, a tree protection expert accompanies all work where adjacent trees are touched.
New building is surrounded by historic structures
The Gründerzeit quarter in Bonn's Südstadt survived the World War almost intact. Where once only the upper middle classes resided, today young families and students also live. They enjoy the proximity to the city centre, the Rhine and many university facilities. The student union Bonn has been located on the Carré Lenné-, Nasse- and Kaiserstraße since 1924 and serves around 46,000 students from here. To make room for a contemporary and barrier-free new building, the existing buildings from the 1940s and 1950s were demolished, except for two historical monuments. In their place, a student house with a refectory, study, work and recreation areas will be built by 2025. In addition, a hall of residence with 106 places and an administration building will be built. An underground car park will leave space above ground for generous green areas. The design by the Berlin office of Baumschlager Eberle Architekten harmoniously ties in with the existing architectural monuments as well as the unique flair of Bonn's Südstadt.