Cracks in Buildings
Cracks result in applied forces greater than those which the building or its part can withstand. These forces may have emerged externally to the building or internally within the building or have been developed in the materials of the building as a result of Chemical changes. There may be a single force or a combination of forces having a single cause or several causes.
This is a residential building at San Francisco. Major cracks have developed on the external facade of the building. The cracks running across the entire facade of the building are diagonally directed and diagonal cracks are generally structural cracks. They occur due to structural problems in the buildings. Structural cracks could be due to major or minor problem in the structural design. Intensity of structural problem is determined on the basis of the intensity of cracks developed.
Most cracks occur due to drying of construction water.
- These are generally superficial
- Do not affect the serviceability of the building
- Can be easily repaired
If cracks are more significant, repair work may be repeated periodically.
Structural significance of the cracks tends to be exaggerated by a natural reaction of the owner.
Many cracks do not have any effect on the stability of structure, because of “high factor of safety”.
Cracking has adverse effects on appearance. Sometimes several cracks go unnoticed for years which affect the performance of the structure.
Rain penetration through a crack depends on:
- Construction of a building
- Degree of exposure
- Capillarity of fine cracks
- Wind driven rain penetration through wide cracks
Major Causes of Cracks occurring in Buildings
- Movements of the ground
- Effect of gases, liquids and solids
- Effect of changes in the temperature
- General (e.g., Vibrations)
In our next article, we will discuss in detail the major causes of cracks in Buildings.