Page 189 - Forensic Structural Engineering Handbook

5.22 ENGINEERING RESPONSE TO FAILURES

INTERVIEWS

Eyewitnesses and other persons with relevant project knowledge can provide the forensic
engineer with information that may be helpful, even essential, to a successful investigation.
(See Fig. 5.17.) Their accounts can be invaluable in formulating hypotheses, focusing the
investigation, and finally arriving at the most probable cause of the failure.
The interviews should be conducted as soon as possible for several reasons:
• To capture the recollection while it is fresh in the person’s memory
• To minimize the possibility of accounts being influenced by what other people saw or
believe happened
• To facilitate identifying and locating witnesses
• To assist in formulating early hypotheses for investigation
In some cases, the forensic engineer may be able to obtain interview transcripts in a
timely manner from other parties, such as from governmental agencies that are investigat-
ing the incident.
In other cases, it may be necessary to obtain interviews directly, or to retain a party
solely for this purpose. The principal advantage of retaining a professional interviewer is
that it allows the forensic engineer to focus on the technical investigation. This is especially
useful if there are a large number of potential witnesses, or if they are not easily identified
or located. Interviewing is an art, and a professional interviewer will use questioning tech-
niques that elicit candid responses and encourage volunteered information.
If an independent interviewer is retained, he or she will need to work closely with the
forensic engineer. The forensic engineer will need to thoroughly brief the interviewer and

West building East building
Horizontal jack
12/Roof slabs Level 6
9/10/11 slabs
Stage IV This package Level 5
in process of
being wedged
Level 4
Stage III Placed day 6/7/8 slabs Level 3
3/4/5 slabs
of collapse
Pour strip Level 2
placed day
Stage II of collapse Level 1
Ground level
Indicates
On On Others wedges were Level C
Stage I line line permanently Level D
“C”
“E”
welded
Level E
(a) Shear wall elevations (b) Building elevation
FIGURE 5.17 Eyewitness accounts, examination of debris, and project records were all needed by the
author to establish the status of construction at the time of the collapse of L’Ambiance Plaza.