Experiment-Based Development of a Design Concept for Crack Repair in Solid Clay as Part of the WIR! GOLEHM Initiative

The aim of the project is to develop a practical planning, design and
construction concept for the structurally effective repair of cracks in solid clay structures using needle-punching. 
Vertical separation cracks are a common and significant cause of damage in existing clay buildings. As they grow in size, leading to a loss of shear interlocking in the
crack area, separation cracks can cause wall structures to become destabilised. Crack formation not only jeopardises the building’s serviceability but can also compromise the
structural stability of the building. Accordingly, to ensure the
durability and structural stability – and thus the usability – of a building, the repair of such cracks is essential.
Crack needling, a technique originating in masonry construction, has also become established as a repair measure in clay construction
, although, in the absence of a design concept, it is currently used solely as a structural measure.
The absence of a crack-pinning method with recognition from building authorities as structurally viable
often leads to the demolition of crack-damaged solid clay walls instead of their repair.
This is to be avoided in future through the development of a design method for crack repair using pinning in clay construction. In developing this method, the key influencing parameters – the construction type of the clay walls, the components of the anchoring system and environmental influences – are to be taken into account through experimental and numerical analysis.
The aim of the test series is to develop a design method for the structural approach to crack repair using needle-reinforcement, taking into account the relevant influencing factors. Furthermore, design and construction recommendations are to be derived from the findings, with the aim of incorporating these, alongside the calculation method, into a WTA technical report on the repair of solid clay structures.