The research project “MOHOHO — Modulares Holzhochhaus,” which concluded in 2024, investigated and developed a modular timber construction system with a focus on urban redensification. Theoretical approaches to circular construction formed the basis for the project and were successively integrated and transferred into a practice-oriented modular system. The objective was to have a building system that is flexible and able to respond to changes in utilization; that, aside from the supporting structure, the construction is replaceable or repairable; and that the materials used are separable by type at the end of their life cycle. In addition to ecological aspects, social and economic issues were also taken into account and combined in a targeted way in order to tap into synergistic effects.
Arising from these considerations was the concept of connecting the high degree of prefabrication of the modular design with the flexibility and resource efficiency of the skeleton structure. In urban space, modular design and construction offers significant advantages due to the short building period and the reduced exposure to noise and dirt. Furthermore, prefabrication under controlled conditions ensures high quality and transparency of the joints, which is essential if the elements need to be repaired or taken apart. The timber frame structure is based on a modular steel construction and the related joining technology. Point load transfer increases material efficiency and enables the modular construction to be extended beyond the high-rise limit (GK 5). At the same time, the flexible structure permits more individualized design possibilities and also adaptations to future changes in use.
A main element is the reversible system node connecting the modules. It enables a redistribution of load, whereby the failure of individual columns or modules does not inevitably lead to the collapse of the entire building, a fact that significantly increases robustness. This offers an alternative to the robustness concepts with tension anchors laid out in EN 1991-1-7, because nonreversible joining techniques such as gluing or casting wood with steel or concrete are not used. The node moreover permits a targeted load redirection, so that damaged elements or modules can be repaired or replaced. The aim is for the repairability and flexibility of the construction system to significantly extend the life cycle and operating life of the building. During the process of deconstruction, the modules can either be reused directly or separated according to type, allowing the building to serve as an anthropogenic inventory of materials.
