Structural Failure In Construction Building

All efforts are essential to prevent structural failure as it involves dangers to human life and property. There are numerous causes for a structural failure, and there is a requirement for a proper analysis of all the factors before construction. 

Since man first began to build, there have been times when our buildings have not met expectations. Common problems include leaks, unsightly cracks or sagging, and in rare instances, total collapse. Modern building codes have greatly reduced, but cannot totally eliminate, the risk of being hurt or killed in a structural collapse. For instance, the risk of death in a car accident (per hour of exposure) is about 35,000 times higher than from a structural failure. But while the probability of structural failure is low, the consequences can be tragic, and engineers continually seek understanding of why buildings fail, who (if anybody) is at fault, how best to repair the damage, and how to prevent similar failures.

Reasons Structures Fail
Defective construction that causes failure may be due to numerous reasons that may not be easy to predict before or during the construction. The major causes of structural failure are defective designs that have not determined the actual loading conditions on the structural elements. Inferior construction materials may also be the cause since the loads are calculated for materials of specific characteristics.

Structure may fail even if the design is satisfactory, but the materials are not able to withstand the loads. Employment of unskilled labor on construction work is another reason for structural failures. Therefore, it is important that the owners, designers, and builders are fully conscious of the reasons of failure, and undertake all preventive measures.

Design Deliberations
Construction imperfection in design and manufacturing can be extremely expensive to settle. Architectural design and construction defects cause a structure to be improper for its proposed intent. Correct structural design is significant for all buildings, but exceptionally essential for tall buildings. Even a slight probability of failure is not acceptable since the results can be disastrous for human life and property. Therefore, civil engineers are required to be exceptionally careful and methodical in ensuring an appropriate building design that can sustain the applied loads. All failure modes need to be examined by using modern software on the subject. However, a designer and a builder cannot be wholly confident about the design, and therefore an appropriate factor of safety is incorporated on the design calculations.

Defects Due to Inferior Workmanship
Defects due to inferior workmanship can lead to structural damage and failure. Poor workmanship is often the origin of construction defects. Even superior quality materials, if used imperfectly, may not successfully serve the planned function, or be as durable as designed. Poor workmanship is the actual cause of most construction defects.

General defects due to poor workmanship are leaking roofs, cracked floor tiles, shedding paint, and other numerous problems. Proper procedures have been created for almost every construction operation, and only implementation is required. A superior quality paint that is applied to an unclean surface is likely to fail, not because the material was substandard, but because it was used with a poor quality of work.

Foundation Failure
Many building foundations are not properly designed and constructed for the existing site soil conditions. Since suitable land is often not available, buildings are constructed on soil that has inadequate bearing capacity to support the weight of the structure.

Furthermore, the near surface soils may consist of expansive clays that shrink or enlarge as the moisture content is changed. Movement of foundation may occur if the clay moistening and drying is not uniform. Vegetation, inadequate drainage, plumbing leakage, and evaporation, may cause soil variation. The top soil layers provide the bearing capacity to hold the structure, and ensure stability of the foundation. If the bearing soil is inadequately compacted preceding construction, the foundation may be affected by settlement. From these experiences from past, the common causes of structural failures are understood. 

The most common causes of structural failures are:
  1. Poor communication between the various design professionals involved, e.g. engineers involved in conceptual design and those involved in the supervision of execution of works.
  2. poor communication between the fabricators and erectors.
  3. Bad workmanship, which is often the result of failure to communicate the design decisions to the persons, involved in executing them.
  4. Compromises in professional ethics and failure to appreciate the responsibility of the profession to the community at large could also result in catastrophic failures.
Other common causes of structural failure are:
  1. lack of appropriate professional design and construction experience, especially when novel structures are needed.
  2. complexity of codes and specifications leading to misinterpretation and misapplication.
  3. unwarranted belief in calculations and in specified extreme loads and properties.
  4. inadequate preparation and review of contract and shop drawings.
  5. poor training of field inspectors.
  6. compressed design and/or construction time.

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