A Bundle of Blogs: On using visual site assessment in forensic investigation

A visual site assessment – including a virtual visual site assessment – is a valuable task in the investigation of a personal injury or failure. This is obvious in the following blogs that I have posted in the past. This type of assessment is particularly valuable during a pandemic.

In a real assessment, the forensic expert (1) gets briefed (2) reads the documents (3) studies existing photographs and drawings, then (4) goes to the site of a personal injury or a failure, (5) examines the exposed surfaces at the site, (6) notes what’s there and what’s not, (7) takes some measurements and (8) additional photographs, (9) gets stills from Google Earth Pro and (10) perhaps video from a drone.

S/he does not (1) look below the surface, (2) take things apart, (3) do intrusive field testing, or (4) laboratory testing. These tasks come later if required.

A lot of data and evidence is gathered this way, sometimes enough to reason to a conclusion and form an opinion on cause sufficient to resolve a dispute or settle a claim.

A virtual assessment – sans site visit and the expert getting his hands dirty and mud on his boots – is also good, and sometimes enough. If it has a shortcoming, the expert doesn’t get “calibrated” to the site as well as he might.

I’ve done several virtual assessments, one a few months ago at the site of a trip and fall. Others of a retaining wall, bridge and building collapses, and a trench cave-in.

Fortunately no lives were lost during the cave-in but an oil tank was taken down. I investigated and reported on the cause after doing your standard virtual visual site assessment (see steps above). My client requested that I not visit the site, not even to drive the nearby roads.

One assessment resolved an 11 year dispute after a four month forensic investigation. A person was injured by ice falling off a structure. In hindsight, that investigation was half real and half virtual – I examined the exposed surfaces with binoculars from a distance.

Interestingly, I got some insight into the formation and risk of ice on structures while coming and going from a ski lodge at Mont Comi on the Gaspe Peninsula. Also seeing ice on buildings during a visit to my daughter’s horse farm in Maine. Forensic engineers work even when they’re playing.


In the following, I’ve listed a few recent blogs on real and virtual visual site assessments that are particularly relevant in COVID-19 times. I’ve posted others in the last 8.5 years but the following are enough.

At the end of the day, while a visual site assessment, whether real or virtual, is often enough for a dispute or claim, it’s not always. Intrusive field work and an in-depth examination of the site is invaluable. “Calibration” of the expert is also valuable.

The Bundle of Blogs on Visual Site Assessment – Real and Visual

  1. COVID-19 and forensic engineering investigation. Posted May 7, 2020 It struck me one morning while walking my dogs that forensic engineering investigation is not prevented by COVID-19.  Experts often work alone as principal investigators conferring with other specialists as needed.  Many of the most experienced experts are sole practitioners.  We already “work from home” in a sense and have for years.
  2. COVID-19 and an initial forensic task a.k.a. a visual site assessment, sans social distancing. Posted June 1, 2020 This blog reminds us that the visual site assessment is carried out by a lonely expert whether for real on site or virtually. Social distancing is not an issue. It also reminds us that it’s an essential task that should be done before the dust settles at the site of a failure or accident.
  3. Get on site and do a forensic visual assessment before COVID-19 returns. Posted September 10, 2020 This seems a bit of a joke this day as the second wave of the pandemic continues to wash over us. But the blog does contain nice comment on how document review, virtual site assessment and on-scene assessments work together to yield a lot of data and evidence on the cause of a failure or accident.
  4. Why did the four story building collapse during construction in London, Ontario. Posted December 31, 2020 I examined the construction site virtually as evident in news photographs and comments by workers. My engineering experience on multi-story building construction identified the probable cause quite quickly. (It’s interesting that two other experienced engineers came up with the same answer, based on virtual visual site examination)
  5. What can you get from a virtual visual examination about the cause of a leaning retaining wall? Posted November 13, 2020 One thing was contributing to a significant reduction in re-construction costs – up to one half! My contribution was based on study of 26 photographs, video from a drone and screen grabs from Google Earth Pro video. I got a lot of data on why the wall was leaning. To be truthful, I could not have done too much better if I had been able to go to the site and do a real visual examination rather than the virtual. This was one of the most satisfying virtual visual site assessments I done.
  6. What can you get from a virtual visual examination of an accident scene. Posted August 28, 2020 I was contacted and sent two photographs of where a person fell and was injured at the entrance to a building. Virtual examination and virtual measuring of the entrance identified contributing factors in the accident. They were so obvious.
  7. Wind, construction crane and inadequate cross-bracing caused Edmonton bridge failure: An initial hypothesis. Posted March 27, 2015 This was one of the most exhaustive virtual visual examinations and data analysis that I’ve done. I also chatted with three structural engineers for insight to add to my own understanding of bridge design and construction. The behaviour of a construction crane in strong winds caused the failure.
  8. Counsel: Your case benefits when you visit the scene of a personal injury accident or engineering failure. Posted April 30, 2016 In a sense, this was a visual site assessment by counsel in a slip and fall case that paid dividends for counsel. He went to the accident site to watch me carry out skid resistance tests. Later management cancelled further expert work including submission of a report on the skid testing. All that counsel had to argue his case was his viewing of what took place – his personal visual site assessment – and my verbal comment on the results as we drove back to the city.
  9. Can you “calibrate” a forensic expert? Posted June 23, 2020 This is a good read, a bit of an eye opener as to what happens to an expert when s/he goes to a site and collects hard data. An expert does get “calibrated” to the scene of an failure or accident during a visual assessment. The process also happens to some extent during a virtual assessment.

Related to the Blogs in the Bundle

  1. Where does an expert’s initial hypothesis come from? Posted February 25, 2019. Updated March 18, 2019 This is a another good read on how we process the data that we get from a real or virtual visual site assessment.
  2. The reliability of an educated guess on the cause of a failure or accident. Posted October 22, 2020. This is a blog we should read on how the reliability of an expert’s opinion might be quantified – at least made less subjective.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada ejorden@eastlink.ca)   

How do you carry out a forensic investigation during a pandemic?

Engineering experience plus data from a visual site assessment carries the day during a pandemic. More often than not engineers know the probable cause of a problem soon after they’re told about the problem.


I blogged in the past about the value of a simple visual site assessment. Simply going to the site of a failure or accident and visually examining what’s exposed at the surface. In a sense, walkin’ around and kickin’ the tires. (Ref. 1)

Never mind taking things apart and seeing what’s beneath the surface. No field testing. No laboratory testing. Nothing like that. Just look and see what’s exposed at the surface.

Then I realized it had to be a virtual visual site assessments when COVID-19 struck. Like in, ‘Stay the blazes home!’. I talked about how valuable these types of assessments are too. (Ref. 2)


Recently I was reminded about the value of simple engineering experience.

A few days ago after blogging about why the multi-story building collapsed in London, Ontario (Ref. 3) I was in touch with an experienced construction engineer in Ottawa, Ted Ruiter. Ted and I are UNB engineering classmates. He was quick to say, “while he hadn’t read my blog yet about the London building collapse”, the probable cause was hurried construction and inadequate support of the concrete floor forms.

Ted’s comment got me thinking about the chat I had earlier still with an experienced design engineer in Halifax, Jamie Yates. Jamie and I are friends. I chat with Jamie at times if a problem seems to have a structural element. We talked about the design of the temporary support of floor forms like those used in the London building. He was also quick to note inadequate support as a cause.

We also chatted about the problems that develop when construction is rushed.

So, the experience of two well-regarded engineers kicked in and quickly pointed the finger at inadequate support – sans virtual visual site assessments.

Of course, that’s not enough – just knowing based on experience – a client wants analysis and reasoning to a conclusion based on the evidence in the spirit of the scientific method. An experienced forensic engineer did that and I concluded inadequate support too.

Three experienced engineers and the same conclusion about inadequate support as the probable cause of the building collapse.


I’m not surprised at the value of plain old engineering experience – the theme of this blog.

I blogged a while ago about the failures that are everywhere in the built environment from the simple to the complex. (Ref. 4) Also the many 100s of ways different structures can fail. For example, 209 for a building alone. (Ref. 5) An experienced engineer knows about many of these and will pick out the probable cause from the many.

Add a visual site assessment to engineering experience and you’ve got a powerful forensic investigative tool.


You can get close to settling your insurance claim or assessing the merit of a case now – from your home office. Maybe even completely settling the claim or reliably assessing merit. You don’t need to wait for the second COVID-19 wave to pass.


  1. COVID-19 and an initial forensic task a.k.a. a visual site assessment, sans social distancing. Posted June 1, 2020
  2. What can you get from a virtual site assessment about the cause of a leaning retaining wall? Posted November 13, 2020
  3. Why did the four story building collapse during construction in London, Ontario? Posted December 31, 2020
  4. You could be excused for thinking that everything is falling down. Posted July 23, 2020
  5. What’s in “…the built environment” and how many ways can it fail? Posted July 8, 2020


(Posted by Eric E. Jorden, M.Sc., P.Eng., Januray 8, 2021 consulting professional engineer, forensic engineer, Halifax, Nova Scotia, Canada January 8, 2021 ejorden@eastlink.ca)