Stuttgart 21 main station - reconstruction of the historical building Bonatzbau
The so called “Bonatzbau” is the historic reception building of Stuttgart's main train station and part of the railway and urban development project Stuttgart 21.
During the re-design, parts of the existing building will be demolished and later rebuilt. During the construction phase, the façade, which is protected as a historic monument, will be preserved and has to be supported as an auxiliary construction. This façade protection is realized with a conventional steel construction as well as with MERO scaffolding technology. The erection of a protective roof is also planned to handle the construction logistics during the construction phases of the building.
Boll und Partner has been commissioned to undertake the structural detailing and implementation planning of the facade supports and the protective roof. and Plans were implemented using the BIM software Tekla Structures. A special challenge is the historical building stock of huge dimensions and the very old and partly incomplete as-built documentation.
Challenges & success factors
The team modeled the existing structures in Revit based on site-measurements and survey reports and imported it as a reference model to Tekla. In addition, 2D and 3D dwg files were imported from other project partners, such as terrain profiles, roads and pipes. By doing this, a very precise construction with minimum steel construction tolerances could be realized. Due to the size and complexity of the project, the clash detection and integration of the steel and concrete structures for this project would not have been possible without a 3D model. It was very challenging to incorporate the steel structures into the existing building. In some cases, spider / crawler cranes had to be used which could fit though a regular doorway. Multi-material modelling including wood and concrete enable the team to calculate exact quantities and costs. The damage to the historically protected façade through fastenings, clamps and drillings was reduced to a minimum.
The project teams worked together using a common collaboration model in a BIM platform and an internal Tekla Structures model with all references. The latter was also used to perform import and export to structural analysis programs such as DLUBAL RSTAB. The exchange was handled via IFC models as well as DWG and PDF drawings. When planning the temporary protective roof, several variations were examined, calculated with DLUBAL RSTAB and distributed as IFC to the project participants. The Tekla model was also used to study the crane setup outside the building, to check the loads and run clash checks during the rotation of the crane
