In catering for movement of a structure, one of three methods can be adopted:
- Design the structure to withstand all the forces developed by restraint of movement. This is possible with smaller structures or structures which are comparatively flexible.
- Subdivide the structure into smaller structurally stable units, each of which the becomes essentially a structure in its own right, able to move independently of the surrounding units. This principle is ideal for controlling those factors such as thermal movement which are related to the size of the overall structure. The disadvantage lies in the need to provide joints between the various units of the structure capable of accommodating all the anticipated relative movements between the units, while at the same time fulfilling all the other requirements.
- Subdivide the structure into fewer but larger sections, and make provision for a smaller number of joints, each with larger movement capacity.