Joints in Building:
The separation or planes of weakness introduced at different locations in a building are known as joints in the building.
Purpose of providing Joints:
The purpose of providing joints at different locations is to accommodate large dimensional changes occurring due to expansion and contraction of the building without structural failure disfiguring cracks or penetration of moisture.
Where Joints Should be provided ?
Joints are usually provided in large or multi-storeyed buildings. But joint should not be provided in shell structures* and certain other rigid structures where joints provided will interfere with the rigidity of the structures.
*Shell structures predominantly resist loads on them by direct compression. That is without bending or flexure. Since most materials are more effective in compression than in bending, shell structures result in lesser thickness than flat structures.