Page 288 - Forensic Structural Engineering Handbook

DESIGN ERRORS, CONSTRUCTION DEFECTS, AND PROJECT MISCOMMUNICATION 8.27

CLOSURE

From the discussion in this chapter, it should be apparent that errors can occur at any stage in
the process from the development of the concept of a structure to its final completion. Beyond
the examples cited in this chapter, designers, contractors, and erectors should be aware of
many other potential pitfalls that have been encountered in practice, some of which are

• Lack of rigidity of foundations on soft soils
• Lack of ductility of structures subjected to dynamic or cyclical loads, such as strong
winds and earthquakes, and lack of consideration for the importance of damping
• Lack of consideration of the importance of designing and detailing for impact and trav-
eling loads in garages
• Lack of consideration of secondary effects associated with, among other things, temper-
ature, excessive bending (P-δ), and bending of short members
• Lack of consideration of unequal deformations between the exposed façade and the inte-
rior superstructure
• Improper location of construction/expansion/contraction joints and associated details
• Lack of consideration of snow drift, ponding, hydraulic pressure on foundation walls in
the absence of proper drainage
• Lack of consideration of the implications of the construction process on the design (con-
structability)
• Lack of consideration of the erection process and its effects on the stability of a partially
completed structure, especially when lateral or torsional stability is involved
• Lack of reanalysis for stability when the erection sequence is changed
• Lack of care in placement of construction loads within the loading limits specified by the
designer, and/or lack of specificity by the designer in that regard
• Substitutions that are not based on an adequate understanding of the design intent
This list provides only a suggestion of the many possible problems that may exist in the
design and construction process. Time pressure, especially under the intense fast-track pro-
ject delivery process, only exacerbate the problem by limiting the opportunity for recovery.
In the final analysis, almost all structural failures may be attributed to human errors. Some
are due to knowledge as yet unavailable and are thus unavoidable; others may occur because
of delayed communication of available knowledge; some are due to ignorance of recently
acquired knowledge; and a few to misunderstanding of accepted knowledge, a rare few to out-
right ignorance, and finally, in exceptional occurrences, to incorrect procedures, mostly in
construction.
We must conclude that in the field of structures, as in any other field of human endeavor,
technological improvements alone cannot guarantee a decrease of failures and may even
increase them. Only a deeper consciousness of our human and social responsibilities can
lead to the construction of safer buildings.

REFERENCES

1. “Investigation of the Kansas City Hyatt Regency Walkways Collapse,” NBS Building Science
Series 143, U.S. Department of Commerce, National Bureau of Standard, May 1982.
2. Matthys Levy and Mario Salvadori, Why Buildings Fall Down: How Structures Fail, W. W.
Norton & Company, Inc, New York, NY, 2002.