Many decisions in design are based on engineering judgement, but not only on the understanding of theory or any computational tools. Even experience in extensive design in academic context can provide only limited perspective in engineering decision making. Most lessons in engineering decision making come from the cases of histories of failures of structures, which itself are the results of a bad judgement, thus making us understand the pitfalls in conceptual design.
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:
(5) lack of appropriate professional design and construction experience, especially when novel structures are needed.
(6) complexity of codes and specifications leading to misinterpretation and misapplication.
(7) unwarranted belief in calculations and in specified extreme loads and properties.
(8) inadequate preparation and review of contract and shop drawings.
(9) poor training of field inspectors.
(10) compressed design and/or construction time.