Im Sträler
LEO Consulting was commissioned to assess the seismic safety of several residential blocks within the Im Sträler housing development in Zurich. The complex was built in the 1970s using the prefabricated Göhner construction system and comprises several hundred apartments.
One of the main challenges of the project was the absence of original construction drawings. To establish a reliable basis for the structural assessment, an extensive historical and technical investigation was carried out. Archive documents, technical literature and documentation from comparable Göhner developments were reviewed and compared with the available survey drawings.
Based on these findings, three-dimensional structural models were developed for the investigated buildings. As the load-bearing behaviour of prefabricated buildings depends strongly on the connections between walls and floors, particular attention was given to their detailed assessment. The resistance of the relevant connection types was determined and compared with the demands obtained from the global structural analysis.
The project illustrates the challenges associated with the seismic assessment of large residential developments built using prefabricated construction systems. In many cases, only fragmented information is available, while the structural behaviour depends heavily on connection details. Nevertheless, a combination of historical research, structural modelling and risk-informed assessment can provide a sound basis for future decisions regarding such buildings.