Some Considerations When Conducting a Forensic Investigation of a Wood Structure

Wood has performed remarkably well as a construction material in a variety of structures for millennia. Occasionally, problems occur that require investigation to understand the nature and cause of the problem. With wood, not all forensic investigations are the result of catastrophic failure, but, more often than not, are related to performance-based issues. Very few catastrophic failures of wood structures resulting in significant financial loss or loss of life have occurred, although it happens. For example, in 1773 the collapse of a timber-frame in a meetinghouse resulted in five deaths and 48 injured. The incident was recorded in detail at the time and may very well be the first forensic investigation of a wood structure in the United States (Clark, 1998). The collapse of the Texas A&M bonfire in 1999 was not a typical structure, but resulted in the death of 12 students (U.S. Fire Administration, 1999). Investigation of this wood structure was very complex and involved numerous professions. Similarly, torrential rains caused the collapse of a three-story building in Mumbai in 2005, which resulted in the death of six people (The Hindu, 2005). Most forensic investigations involving wood may be less noteworthy than these, but all should follow the same investigative process as that for any catastrophic or performance failures. The investigative process is described by the American Society of Civil Engineers (ASCE, 1989). Additional resources that describe the forensic process or provide case studies include Nicastro (1997), Carper (2001) and Ratay (2000). While not necessarily intended as forensic engineering references, there are numerous sources of information that can help explain why a failure occurred, such as Perrow (1999) and McDonald (2003). The purpose of this chapter is to identify key steps in the investigative process of forensic engineering and emphasize aspects that should be considered for wood structures.