Comparatively, modern buildings are more prone to cracks being tall and slender or large in volume and also have thin walls particularly external walls. Almost all Modern buildings are designed for higher stress and built at a fast pace. Whereas old buildings were designed for under stress and also built at a slow pace. Modern buildings use various materials & material mixes.
Modern buildings are therefore, more crack prone as compared to old buildings which used to be low and also had low thick walls.
Moreover, it is likely that moisture from rain can easily enter and spoil the finishes of the newly constructed buildings, which has thin walls. Thus measures for control of cracks in buildings have assumed much greater importance on account of the present trends in construction.
Courtesy - 123rf
7 Causes for Occurrence of Cracks in Modern Buildings:
Cracks mostly result from strains which induce tensile stress in excess of the material’s capacity. To prevent or minimise the occurrence of non-structural cracks, it is necessary to understand the basic causes and mechanism of cracking, and certain properties of building materials.
The Principle Mechanism Causing Non-Structural Cracks in the Building are:
- Moisture change
- Thermal movement
- Elastic deformation
- Chemical reaction
- Foundation movement & settlement of soil
- Growth of vegetation
Strain develops due to excess loads, restraint of volume changes, or material behaviour. Volume changes generally occur due to changes in temperature and moisture. Influences on material behaviour include freeze-thaw cycles and reactions between cement and aggregate.
Overloads mostly arises due to the dead (self) weight of materials, the live load of equipment and people, soil and water pressure as well as wind, snow, and earthquakes can also produces cracks.
Deflections and deformations imposed by foundations, frames, roof slabs, and other structural elements also cause cracking (it might cause structural cracks too).