The joining technique of plugging has a century-old tradition in timber construction and is still widely used today, for example in prefabricated concrete construction. 
Two main approaches to plug connections can be distinguished: highly complex nodes, which are very stiff but difficult to detach, and simpler connections that are easy to assemble and detach. 

There is always a project-related balancing between these two objectives. 


Locking:
One of the difficulties of plugging as a wood joining technology is the fixation of the components through their geometry. Purely geometric approaches allow for pieces to be joined in a way that they can only be moved in one dimension. With more than two components, the pieces can be joined in a way that they can only be assembled and disassembled in a specific sequence. Another approach is to stabilize the joint through loading it. 


Cross-Section Reduction:
Very complex joint geometries needed for very stiff connections often require a high proportion of the beam cross section to be allocated for stabilization and leave only a small percentage to be used for the transfer of the main loads. Several approaches have been developed here:

- local enlargement of the cross section
- additional connection element
- elongation of the joint
- separating load transfer and fixation of the element


Stiffening:
Stiffening of the joint is an important issue due to the limited ability of the connection to transfer momentum. Here, too, there are a number of widely used solutions:
- staggered cantilevers (traditional Japanese)
- plates (balloon frame)
- diagonalized constructions (Central European half-timbered buildings)
- multiple connections acting together (grates)
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