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Repairable buildings with prefabricated timber modules at the core.
Timber may well become the cornerstone of future high-rise buildings, with researchers at Graz University of Technology (TU Graz) in Austria developing a prefabricated timber module system aimed at extending the lifespan and adaptability of buildings. Their innovation combines modular and skeleton construction to address sustainability challenges in the construction industry. (main pic: The modules can be arranged side by side or stacked vertically, allowing for adaptable floor plans. Credit: IAT – TU Graz.)
“If a property is no longer fit for purpose, it is usually demolished even though it would still be perfectly usable,” researchers noted. This new approach seeks to reduce resource consumption by allowing damaged sections of a building to be removed and replaced without demolishing the entire structure.
A Circular Approach to Building
The construction sector consumes up to half of global raw materials and accounts for nearly 40% of greenhouse gas emissions. TU Graz researchers, alongside partners Kaufmann Bausysteme and KS Ingenieure, focused on circular strategies such as refurbishment and reuse to create an environmentally conscious building solution.
Christian Keuschnig of TU Graz explained: “That’s why the circular R-strategies, such as refurbishment, repair or re-use, were very important for us in the MOHOHO project, in order to develop a building system that offers a CO2-reduced alternative to conventional construction methods in high-rise construction.”
Prefabricated timber modules, combined with a skeleton structure, form the heart of the system. Cross-laminated timber floors and glulam beams and columns provide strength and flexibility, while the innovative node connection redistributes loads to prevent catastrophic failure.
Flexible and Repairable Design
The modular timber design enables buildings to reach up to 24 storeys, although a concrete core would be required for structures taller than six storeys. This innovative approach not only ensures safety but also simplifies repairs.
To replace a damaged module, utilities such as electricity and water are disconnected, and a lifting cylinder is used to remove pressure on the module. This allows it to be replaced without disturbing the rest of the structure.
Keuschnig highlighted the advantages of this system: “The prefabrication of the modules in a production hall under controlled conditions enables higher quality and traceability of the joints compared to on-site assembly, and ensures shorter construction times as well as reduced noise and dirt pollution. The repairability and flexibility of the construction system should significantly extend the operating life and lifespan of the building.”
A Blueprint for Sustainable Construction
The project, supported by the Austrian Research Promotion Agency (FFG), offers an insight into how modular timber construction could transform the building industry. Modules can either be reused directly or separated into their components during dismantling, promoting resource efficiency.
As the team prepares for a follow-up project, Keuschnig emphasised the potential impact of this approach: “During dismantling, the modules can either be reused directly or separated by type. We are already planning a follow-up project in which we want to test and scrutinise all of these things in practice.”
