Page 183 - Forensic Structural Engineering Handbook

5.16 ENGINEERING RESPONSE TO FAILURES

• Notes of persons met and information thus gained
• A record of instructions given
Field notes should be made with the mentality that they are an irreplaceable record of
first-hand observations, and that other persons may need to understand them, possibly
many years in the future, without the benefit of explanation. As such, every effort must be
made to make them self-explanatory, legible, accurate, and to keep them well organized.
Legends and explanatory notes about what is depicted will assist tremendously in this
regard. Dedicated bound field books can be useful for keeping notes organized. Field notes,
whether bound or loose, should be dated, pages numbered, and the preparer identified.
Permanence is better assured if the field notes are made in ink, rather than pencil or marker.
Redundant record keeping by different observers is a useful technique for cross-checking
the accuracy of the information collected.
Care should be taken that the observer’s notes remain factual in nature and refrain from
stating preliminary conclusions, since they may at some point have to be turned over to
attorneys for other parties.

Photographs
Photographs are, of course, vital to a forensic investigation. They provide a visual record
that is invaluable for documenting observed conditions, they can assist in determining the
cause of the failure, and they are persuasive in reports and presentations.
The use of digital cameras in forensic engineering has virtually replaced the use of film
cameras. Digital cameras provide “instant” photos, without the need for film processing,
and very inexpensively. Digital images can be rapidly distributed electronically, via e-mail
or Web sites, and they can readily be incorporated into reports and presentations. Due to
the ease by which digital images can be modified, there is always the possibility that an
image may have been electronically manipulated such that it no longer accurately repre-
sents the conditions observed.
To ensure the lasting value of images, whether they are digital or film-based, it is impor-
tant to be organized. Nothing is more frustrating than to have a key photograph, and not be
able to determine who took a photograph, or when, or exactly where. It is somewhat easier
to be organized with digital photographs, since the time and date are automatically stored
with each image. But there will usually be more images to manage, due to the low cost and
convenience of creating the images. And, if there are multiple photographers, coordina-
tion is required. Information that should be kept with each image includes—at the absolute
minimum—the date and the photographer. Often, more detailed information is needed,
such as location, description of the component, and what activities were underway at the
time of the photograph. A log with a short caption for each image can be very valuable.
Seldom can a photograph stand on its own. But some techniques can help make pho-
tographs more self-explanatory, such as
• Begin a series of photographs with an overall photograph of the structure. Then, from
about the same angle, take close-up photos of each item of interest within the frame of
the overall photograph. The overall photograph can then serve as a “keyplan” for the
close-up photographs.
• Make sure the time and date are properly set on the camera.
• Label components before photographing them, and make sure that the label is visible
within the frame. For example, “West end of member XYZ” or “Probe #15.” If it is not
possible to label the actual component, or if the label cannot be visible within the frame,
an alternative is to write a label on a card and to place the card within the scene.