Real and virtual visual site assessments

A visual site assessment – either Real or Virtual – is a valuable task in the investigation of a personal injury or a failure in the built environment. I explain this in the Bundle of Blogs below that I posted in the past. This type of assessment is particularly valuable during COVID-19.

In a Real assessment, the forensic expert does the following tasks:

  1. Gets briefed by the client
  2. Reads documentation on what happened
  3. Goes to the scene of the personal injury or failure,
  4. Examines the exposed surfaces at the site
  5. Notes what’s there and what’s not
  6. Takes some measurements
  7. Also some photographs
  8. Perhaps gets video from a drone
  9. Gets “calibrated” to the site (Ref. 1)

S/he does not do the following that come later if required:

  1. Look below the surface
  2. Take things apart
  3. Do intrusive field testing, or
  4. Laboratory testing

What is done during the Real assessment process is not too much different from the SOAP (Subjective Objective Assessment Plan) and Differential Diagnosis processes in medicine. (Refs 2, 3)

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 – 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. Nor get his hands dirty and mud on his boots. (Ref. 4)

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

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 visual site assessment was half real and half virtual – I examined the exposed surfaces with binoculars from across the street.

At the time of this investigation I got insight into the formation and risk of ice on structures during a ski trip to Mont Comi on the Gaspe Peninsula. The penny dropped as I came and went from the ski lodge. Ice formed at the eaves trough till it got too heavy and fell off. Signs warned skiers of this. I also saw ice on buildings during a visit to my daughter’s horse farm in Maine. Forensic engineers are working even when they’re not.


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 nine years but the following are enough.

At the end of the day, while a visual site assessment, real or virtual, is often enough to resolve a dispute or claim, there are situations where field work must be carried out.

A Bundle of Blogs: The value of Real and Virtual Visual Site Assessments

  1. How do you carry out a forensic investigation during a pandemic? Posted January 8, 2021 The blog notes the value of plain old engineering experience. But, when coupled with a virtual visual site assessment, invaluable and more reliable still. Three engineers found the same cause of a building collapsing, two based on experience alone. The third based on experience plus a virtual visual site assessment.
  2. 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.
  3. COVID-19 and an initial forensic task a.k.a. a visual site assessment, sans social distancing. Posted June 1, 2020 The blog reminds us that the visual site assessment is carried out by a lonely expert whether 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.
  4. 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 a fourth wave threatens 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.
  5. 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.
  6. 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. He went to the accident site to watch me carry out skid resistance tests. Management later cancelled further expert work including submission of a report on the skid testing because the firm underestimated the cost of expert services. All that my client had to argue his case was his viewing of the field testing, photographs he had taken and my verbal comments on the results as we drove back to the city.
  7. “Technical” visual site assessments: Valuable, low cost, forensic engineering method. Posted September 4, 2012 The blog explains that the visual site assessment is a basic initial task in a forensic investigation. Sometimes it’s all that is necessary in the gathering and analyzing of data on the cause of an accident or failure.

Examples of Real and Virtual Visual Site Assessments

  1. My personal slip, trip and fall accident. Posted September 2, 2021
  2. Why did the four story building collapse during construction in London, Ontario? Posted December 31, 2020
  3. What can you get from a virtual site assessment about the cause of a leaning retaining wall? Posted November 13, 2020
  4. What can you get from a virtual visual examination of an accident scene. Posted August 28, 2020
  5. Wind, construction crane and inadequate cross-bracing caused Edmonton bridge failure: An initial hypothesis. Posted March 27, 2015
  6. Falling roof ice injures man. Posted January 18, 2013
  7. Gabion retaining wall collapse results in litigation. Posted February 9, 2013

Related to the blogs in the Bundles above

  1. The reliability of an educated guess on the cause of a failure or accident. Posted October 22, 2020.
  2. Where does an expert’s initial hypothesis come from? Posted February 25, 2019. Updated March 18, 2019


  1. Can you “calibrate” a forensic expert? Posted June 23, 2020
  2. Using SOAP notes in forensic engineering investigation. Posted February 6, 2014
  3. Differential diagnosis in medicine and forensic investigation, and soft, initial thoughts on cause. Posted December 20, 2019
  4. An expert’s “dirty hands and muddy boots”. Posted December 20, 2013

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada September 14, 2021   

My personal slip, trip and fall accident

I don’t recommend it but the trip and fall accident I had recently has certainly opened my eyes and added to my experience investigating the cause of these types of accidents.

I got insight in a hurry on how easily it can happen and how the tiniest feature at a slip, trip and fall site needs to be investigated. You can’t beat personal experience, but if I had a choice I would have passed it up in a heart beat.

I tripped on the curb in a parking lot and fell hard – face down – on a concrete sidewalk. I had just got out of my car at a building where I was picking up some safety equipment. The building had a closed Covid-19-look and I was looking up – while walking forward – for a sign on how to alert people that I was there. When down I went after tripping on a simple curb – or so it seemed simple.

Curbs are everywhere and we walk across them all the time so what happened this time?

I visually examined the site a couple of days later when I had recovered a little. The curb in the parking lot looked well built. But I also got the impression it was a little higher than curbs in general.

I looked more closely where I had tripped and there was no question the curb was higher there. It gradually got higher from the parking lot in general to the place where I fell. A rough measure indicated 7.9 inches compared to 6.7 inches in the parking lot.

I went back later and measured the height of the curb where I fell and compared this to measurements of the curb farther along. I also compared the height to the curb on the other side of the 40 foot wide parking lot.

I then compared the height of the curb in the parking to that in the parking lot of an apartment building and also to the curb on the residential street where I live.

This is what I found:

  1. Height of curb where I fell … 7.9 inches
  2. Height of curb farther along … 6.6 inches (1.3 inches lower)
  3. Height 40 feet across the parking lot … 5.7 inches (2.2 inches lower)
  4. Height of curb in an apartment building parking lot … 5.6 inches (2.3 inches lower)
  5. Height of curb on my residential street … 5.1 (2.8 inches lower)

Note the differences from where I fell compared to where people might be expected to step up and over the curb after getting out of their car: 1.3″, 2.3″ and 2.8″ lower.

I concluded that expectation‘ played a part in my fall. Like all of us, I walk over curbs all the time without looking down, expecting them to be a typical and uniform height. I certainly don’t expect the height of a curb to change within a few feet.

And, as turned out at the site, the curb wasn’t built higher, there was a depression in the parking lot surface exposing more of the curb.

It was easy to see this by getting down on your hands and knees and looking along the top of the curb and seeing that it was uniformly graded. It was also easy to see that the parking lot was not uniformly graded at my accident site.

It was either built this way or subsided on a compressible sub-grade – the foundation soils beneath the pavement were compressible.

Why didn’t I see the subsidence in the pavement? Well, it’s not something you expect to see in a parking lot surface. The accident site is in an area of town that is relatively new with a well designed and constructed look.

The personal experience take-away from this?: Respect for how a simple one or two inch (1″ or 2″) change in level at a site can can cause a serious trip and fall accident. The cause of the tiniest, irregular feature at a site must be investigated – why the subsidence in the pavement at this site? Luckily I got out of this with my head intact – no concussion – but it could have been worst.


The height of the curb was quite a revelation but so too was the attention I got after I fell. I remember lying there on the concrete sidewalk with head and shoulders on the lawn by the sidewalk. Stunned for a few moments then trying to get up to lie against the post marking the location of the disabled parking lot.

More moments passed and I was conscious of a pickup truck stopping and the driver jumping out and running towards me calling out to his assistant to bring the first aid kit. Then conscious of a woman and a guy coming out of the building. And another woman with an oatcake. All asking if I was okay; the truck driver getting down to help me up against the disabled post. I learned later that my face was a bloody mess to look at by all those on the sidewalk with me.

I heard a first-responder’s siren off in the distance and wondered where they were going in a hurry. I quickly learned to me, brief minutes after I had fallen. Impressive. For sure my face prompted someone to call 911.

Lots of questioning and testing of my vitals followed. Through it all I explained why I was there and produced a form for the safety equipment – I was determined to follow through on why I was there. I also imagine I was being engaged in conversation as part of the assessment.

More minutes passed, a chair was brought out and I managed to get on it. The vitals were all pretty good, not perfect considering the whack I got but okay. Then suggestions from all around to go to Emerg. No way I was going there considering the wait-time reputation these places have and signed off to that effect with the first responders.

More time passed and I managed to walk into the office building and sit down in a recreation area. As determined as I was to push back against this broadside I realized I shouldn’t drive in rush hour traffic and called neighbours who came and got me. While waiting I got up and walked around the recreation room several times, taking back my life.

My resolve was challenged again in the evening when two of my daughters called on FaceTime on a family matter – surprised, to say the least, to see the messy face and hear the trip and fall report.

Considering that both are in medical fields I got more questions about going to Emerg and comments from them on brain bleeding, concussion and not waking up in the morning. I just couldn’t go there and those moments passed. I was beginning to feel quite okay then but I did agree not to drive the next day.

I learned a few hours later from a medical doc friend that brain injury would have presented within short hours of my fall. I was sorry to be awkward about going to Emerg with the women and man who were quick to act, the first responders who were good, and my daughters who were concerned – I just had to push back.


(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada September 2, 2021   

(Note: The foregoing is not a report on a forensic engineering investigation)

Super experts: Only in the U.S. of A., you say?

More than 2,000 people in the U.S. see themselves as expert enough to pay for a listing in the SEAK, Inc. Expert Witness Directory 2021. Fair enough. What’s troubling is that each of them, on average, claim 11 different areas of expertise. Phew!

Do the numbers: Divide 23,000 different types of problems, disputes and failures identified by SEAK in the listings by the 2,000 experts.

You can do the counting and dividing yourself at

For example, in the technical field:

R.A.H. Professional Engineer, Florida, Areas of Expertise: – –

  • Structural engineering
  • Civil engineering
  • forensic
  • Structural damage assessment
  • Building collapse
  • Construction defects
  • Storm damage
  • Fire loss
  • Sinkhole investigation
  • Roof collapse
  • Peer review
  • Water intrusion
  • Roof evaluation
  • Repair recommendations
  • Retaining walls
  • Storm water drainage
  • Structural failure
  • Scope of damage

Also in the technical field:

G.L.R. Plumber, Newport, Michigan Areas of Expertise:

  • Plumbing
  • Fire-plumbing system design
  • Plbg codes and product standards
  • Fuel gas codes
  • Fuel gas fires/explosions
  • Mechanical codes
  • Scald
  • Hot water system
  • Temp controls
  • High rise bldgs
  • Legionnaires disease investigations
  • Legionella standards and guidelines
  • Piping/pump/valves/dezincification
  • Floods

In a medical field:

L.Z.J. Medical doctor, Massachusetts Areas of expertise:

  • Orthopedic surgery
  • Sports medicine-shoulder
  • Sports medicine
  • Knee injuries
  • ACL injuries
  • Meniscus
  • Arthroscopie surgery
  • Rotator cuff

These are just three (3) of the 2,000 profiles submitted by the experts to the SEAK Expert Witness Directory.

There’s no question if you’re looking for a particular specialty this is a source. I blogged on this in the past. (Ref. 1)

For example, I had a file that needed someone knowledgeable in tool design and manufacture. On another occasion, someone who could date the age of contaminated soil from an old oil spill.

But it did occur to me on scanning SEAKs 2021 catalogue that you’ve got to be careful. I ask a lot of questions before I retain someone to support a forensic investigation. I then function as the Principal forensic investigator, as defined by the American Society of Civil Engineers (ASCE), incorporating the expert’s findings in my forensic investigation and analysis. (Refs 2, 3)

What’s not so good about a question-less situation is that the injured party or their agents – a litigation lawyer or insurance claims manager – doesn’t know that the dispute resolution process is not getting good forensic service. We have our multi-area-of-expertise experts up North too.

I know about a foundation subsidence problem investigated by an engineer who attributed the subsidence to poor concrete foundation construction. No thought was given to the geotechnical properties of the deep layer of poor soil fill beneath the concrete foundation, a field of study completely alien to the engineer’s field of study and practice. But the expert presented well in a dark suit.

I learned about this on reading the report a couple of years after the dispute was resolved – to the detriment of who, I wondered?

For sure there are very knowledgeable people in the U.S. of A. and also up North. There are also those who walk and talk good, but do work that wouldn’t stand up to peer review.

When you question, ask the expert how many files s/he has processed in the areas of expertise claimed. Do this in the same way as SEAK asking the expert registering in their 2021 Directory how many times they have given testimony in court in the last four (4) years. Numbers tell the story in more ways than one.


  1. An expert for every type of dispute and claim in SEAK’s Expert Witness Directory 2018. Posted November 30, 2017
  2. Lewis, Gary L., Ed., American Society of Civil Engineers (ASCE), Guidelines for Forensic Engineering Practice, 2003
  3. American Society of Civil Engineers (ASCE), Guidelines for Failure Investigation, 1989

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, August 24, 2021   

Grandma sez, based on observation – and so do forensic engineers

Cindy Day’s grandmother predicted the weather the same way forensic engineers initially hypothesize the cause of a failure or accident – by ‘accumulated wisdom and careful observation‘. (Ref. 1)

I was struck by this as I read Cindy’s book, ‘Grandma Says’ – and the fact the two of them get their predictions and hypotheses right a lot of the time based on little evidence. This as confirmed by science in weather forecasting and more detailed forensic investigation in engineering.

‘Grandma Says is a collection of 80 weather-related sayings and prognostications about the weather based on traditional sayings and experience’. Most weather lore is based on careful observation of nature’s cycles or of animal behaviour. (Ref. 1)

I’m reading the book and noting which of Grandma’s 80 sayings are based on simple observation but well supported by science – so far, many.

For example:

  • Morning dew on the grass, rain will never come to pass. That’s because the air temperature drops on a clear, windless night to the dew point – the point when the air is saturated with moisture. Condensation then occurs and appears as dew on the grass. These conditions exist in the centre of a fair weather system.
  • If the dog is acting up, there’ll be thunder before long. This is because they can smell increased concentrations of chemicals in the air associated with a storm, like ozone which has a metallic scent. They can also hear thunder long before we do. My two dogs do that.
  • It’s not snow, it’s poor man’s fertilizer. That’s because snow contains a lot of nutrients, like nitrogen, for example, and a lot of moisture. If the snow falls on unfrozen ground in the spring, the nutrients penetrate the soil and do some good, like fertilizer.

I’ve mentioned different times how an expert’s initial hypothesis – an educated guess – on the cause of an accident or failure is based on a (1) visual assessment of a site, (2) preliminary data and (3) experience. I’ve even ventured to estimate the percent probability that the hypothesis will be borne out by additional forensic investigation. (Ref. 2) This is the approach in both science and applied science (engineering).

For example, as mentioned in the following blogs:

  • A Bundle of Blogs: Using visual site assessment. Posted January 25, 2021
  • What can you get from a virtual visual site assessment of a retaining wall on the verge of failure? Posted November 13, 2020
  • “Calibrating” a forensic expert. Posted June 23, 2020
  • “Technical” visual site assessment. Posted September 4, 2012

I’ve demonstrated the application of experience and observation by hypothesizing the cause of failures reported in the news, and noted the potential for failures in the future – see the following list.

I study these failures to get more experience. The correctness of my educated guessing has been endorsed by local colleagues in engineering, and others away and overseas. We’re getting it right most of the time based on experience and observation – like Cindy’s Grandma.

For example:

  • Condo collapse, Miami, Posted July 14, 2021
  • Cost overruns, Ottawa Posted June 22, 2021
  • Building collapse, London, Posted December 31, 2020
  • Retaining wall failure, Ottawa, Posted November 13, 2020
  • The potential for failure, Everywhere, Posted July 23, 2020
  • Bridge failure, Edmonton, Posted March 25, 2020
  • Crane collapse, Halifax, Posted September 20, 20019
  • Bridge collapse, Italy, Posted October 5, 2018

Farmers, gardeners, outdoor people, dog owners and forensic engineers are all doing it – forecasting the weather and the cause of problems. If truth be told, I can imagine the young farm girl is alive and well inside Cindy Day, the meteorologist, and that she is still forecasting the weather, like Grandma did, on her drive to work each day.

For sure, Cindy’s checking the charts and hard data before going public with the weather forecast. But still having fun on the drive observing, estimating and learning based on wisdom and experience – like engineers do – and getting it right often enough.


  1. Day, Cindy, Grandma Says, Weather Lore from a Meteorologist, Nimbus Publishing, Halifax 2012, 2013
  2. The reliability of an educated guess on the cause of a failure or accident. Posted October 22, 2020

(Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada Posted July 28, 2021

Hot-tubbing and group peer review of expert’s reports

What is hot-tubbing but group peer review? And if group therapy is good when we’re down in the dumps then group peer review – hot-tubbing – is good when we’re in dispute.

Hot-tubbing with experts and their reports is increasingly recognized as a good way to resolve a dispute. (Refs 1 and 2) If the reports were peer reviewed before they were taken into the tub, so much the better.

Hot tubbing involves experts retained by different parties to a dispute getting together, reviewing each other’s report and agreeing a single report. Also noting where they can’t agree. It’s getting more popular in Canada and the UK and is widely accepted in New Zealand and Australia. Not so much in the adversarial U.S. of A.

Peer review involves a similarly qualified person(s) thoroughly and objectively evaluating an investigation of something and the conclusions drawn. For example, the cause of a failure or accident in the built environment. Sometimes the persons involved are not known to one another. Peer review has been around a long time in science and increasingly relied on in engineering.

I thought, if both are good, get them together in the hot-tub – experts with peer reviewed reports. But watch carefully and don’t let them in unless their forensic investigations and reports have been peer reviewed.

It’s interesting, that as good as it is, the hot-tub process did not involve experts in it’s development. (Ref. 4) Get experts involved now in the hot-tub process and perhaps we can tweak it from the inside to another level of excellence.


  1. Biased experts cured with a soak in the hot tub. Posted January 31, 2017 This is a real good read
  2. “Hot-tubbing” experts reduce the cost of civil litigation and ensure objectivity. Posted March 31, 2018 Another good read
  3. A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted November 19, 2019
  4. Corbin, Ruth M., The Hot-tub Alternative to Adversarial Expert Evidence, The Advocates Journal, Spring, 2014 (Dr. Corbin is Chair, Corbin Partners Inc., Ontario)

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada July 23, 2021   

Why did the Miami condo collapse?

It’s easy for a forensic engineer to identify the probable cause of a failure in the built environment based on preliminary data – to give an initial hypothesis. (Ref. 1) Collapse of the 12-story Miami condo on June 24, 2021 is no exception.

We do this based on:

  • A briefing by the client
  • Reading the documents
  • Our experience and observation over time

The briefing and documents in this case were news reports and photographs, an engineering report and a research report.

The collapse was not a disaster waiting to happen. It was a disaster unfolding over 40 years since construction of the condo in 1981. Slowly at first then real fast – the collapse. (Refs 2, 3 and 4)

What’s the evidence?

  1. The condo was a reinforced concrete structure. Columns, beams and floors were made of concrete reinforced with steel for greater strength. Steel rusts in water and loses strength. (Ref. 5) You can see this type of construction underway in our towns and cities where ever there is a tall crane – for example, today on Prince Albert Road in Dartmouth, Nova Scotia.
  2. An engineering study in 2018 found the concrete spalling – exposing the steel to water. (Ref. 3) The study reported major structural damage and ‘abundant’ cracking. Example locations included the concrete slab below the pool deck and in the parking garage. Cracking could be expected in the concrete columns, beams and balcony floor slabs.
  3. The condo foundations were supported on limestone, reportedly soft and porous. (Ref. 2) Limestone is soluble in water – it dissolves in water. Think sinkholes in Nova Scotia and elsewhere.
  4. The source of the water? The condo site was a former wetland on a barrier reef an estimated couple hundred feet inland from the ocean and a couple metres above. (Ref. 2) This means the groundwater – for certain, salt water – was in the limestone supporting the foundations and not far below. This is like the water level that you see in a dug well. This is a harsh (marine) environment for exposed steel and soluble limestone.
  5. Another source of water? There were reports that the deck of the swimming pool and the floor of the parking garage were poorly drained. (Ref. 3) These wet surfaces would be near the level of the foundations that are supported on limestone.
  6. A study by a professor at Florida International University found that the condo was sinking steadily since the 1990s. (Ref. 4) That’s what happens to condo foundations supported on limestone that is softening over time.

So, where’re we at with respect to cause?

The condo foundations were subsiding (sinking) on the soft limestone for years causing the columns above to settle – move downwards. Excessive foundation settlement is a failure in itself and certain to have contributed to the collapse, and possibly been the main cause.

This vertical movement of the columns stresses the steel reinforcing the concrete and the steel connecting the beams and floors above to the columns. This is the steel weakened by water over time – the structural distress reported in 2018.

In time, this movement over-stresses the steel causing the connections to break and the condo to fall down – collapse.


That’s an initial hypothesis as to cause based on press reports and photographs – preliminary data for sure but still something. And better than nothing when seeking comfort at such a loss of life.


(It’s interesting that the engineering study in 2018 did not comment on the foundations and the underlying porous limestone nor on the fact that the condo was sinking since the 1990s. Possibly because it appears to have been a visual structural assessment of exposed surfaces. Still, red lights if ever there were any – porous limestone and a sinking condo)


  1. Where does an expert’s initial hypothesis come from? Posted February 25, 2019
  2. Various news reports, pictures and video after the collapse on June 24, 2021
  3. Report of a structural assessment by Morabito Consultants, Inc., Miami on October 8, 2018
  4. Study of building subsidence by a professor at Florida International University, Miami
  5. Why did the bridge collapse in Italy and how might Advocates have known this could happen? Posted October 5, 2018

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada July 14, 2021 and updated July 18, 2021   

Taking visual assessment during forensic work to the next level, with eye-level, “aerial” video

The penny dropped recently when I realized I can get eye-level “aerial” video during one of the most important tasks in a forensic investigation. I can then examine the data at my leisure and easily share it with others.

I’m talking about taking video during the visual examination at the site of a failure or accident. This examination is one of the first tasks we do during a forensic investigation, and it often points to the cause of a failure or accident: (Refs 1 to 4)

  • Get briefed by the client on the failure or accident
  • Read the existing documents
  • Walk and visually examine the site
  • Next …

We take video in the same way that a snow boarder catches ‘huge’ air off a jump and captures it with a camera mounted on his helmet – like my 13 year old grandson, Jonah, in Maine.

I did this a few days ago during a test with a GoPro camera mounted on my helmet and got the following data to analyse later and share with my ‘client’:

  • A video of exactly what I was looking at on the building site and the terrain beyond, and the ability to take off stills or frames split seconds apart
  • Dictated comment on what was important in the scene as recorded by the GoPro camera – for example, the cracks in a brick wall, erosion of a bridge abutment, the height of flood waters, flora discoloration at a contaminated site, stair construction at a slip and fall, etc.
  • Dictated surface measurements of important features in the scene – for example, the size and configuration of cracks in a wall, the width of a stair tread and height of the riser, etc.
  • The compass direction of where I was looking
  • My location along the walk
  • My height relative to where I started
  • My elevation above sea level

All this data from simply walking across the site and recording on video exactly what I was looking at – rather than in memory or notes in a field book; the old way. The data is displayed on the video screen courtesy of the GoPro app that is free with the camera.

During my GoPro test I could have visually examined the inside of the building and got a wealth of data there as well.

In a similar way, in a recent forensic investigation I mounted a GoPro camera on the dash of my car and drove along a road during a safety assessment. I simulated what a car driver would experience and captured it on video for study, analysis and sharing later.

Also on that occasion, I took aerial video from a GoPro camera mounted on a drone in addition to the eye-level ‘aerial’ video from the camera on the dash.


It was the success of the road safety assessment and simulation that got me thinking, “Why not eye-level, ground zero video of all failure and accident sites during the initial visual examination?”. That’s what I will do now. Then give a DVD of the video to all interested parties to see – rather than tell them what I remember based on notes in my field book.


  1. A Bundle of Blogs: On using visual site assessment in forensic investigation. Posted January 25, 2021
  2. Can you “calibrate” a forensic expert? Posted June 23, 2020
  3. What can you get from a virtual visual site assessment about the cause of a leaning retaining wall? Posted November 13, 2020
  4. “Technical” visual site assessments: Valuable, low cost, forensic engineering method. Posted September 4, 2012


The test described in this blog was organized by Robert Guertin, Millenium Film and Video Productions Ltd, Dartmouth, N.S., Canada.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada June 30, 2021   

What happened to the “standard of care” – the degree of care that a reasonable person should exercise?

I was quite taken by the news report that appeared in the Ottawa Citizen Saturday, the 12th – see Appendix below. This was news about construction of the 15-story high-rise on Cleary Avenue at Richmond Road. It was sent to me by a friend in Ottawa, and commented on by another friend there, an engineer.


If you don’t mind me saying, I believe both the City and the Developer should have carried out engineering assessments of the impact of the high-rise on the area. Assessments by conscientious, well qualified engineers, not by a town planner for the City and whoever for the Developer.

Engineers who are experienced in foundation and geotechnical engineering, considering the 15-story height of the building and the underground parking garage. Tall buildings are a big weight on the ground and the construction of deep basements can undermine the ground nearby and anything buried in it.

This is what reasonable people would expect to see done – the average man in the street.

I looked at this area on high resolution Google Earth photographs. I can’t believe the City didn’t know the location of the four foot diameter, high pressure water main in such a well planned, well developed, up-market area. That pipe is bigger than the average buried infrastructure.

There’s a wealth of published information on built-up areas like this, as noted by my well experienced, construction engineering friend in Ottawa.

I was surprised that the judicial process didn’t think the City was under any obligation to provide accurate information to the Developer. Nor that it was necessary for the Developer to hire his own engineer.

I can’t believe the Developer didn’t understand the effect of a deep excavation on the ground beyond the parking garage – a distance in the order of the depth of the basement in some poor soils.

Or, for example, understand the effect of driving sheet piling to form the basement walls – there’s always some vibration to the ground during installation and some movement of the sheet piling later. There are other methods of constructing basement walls like this, and they all adversely affect the ground a little outside of the wall.

I think the Developer did understand so why didn’t he hire an engineer to check what the City was giving them? Just do it considering the importance.

Don’t mind me saying, but if experienced engineers were making the decisions here this issue would not have developed and I wouldn’t be asking these questions. But it reads like a Town Planner was making the decisions for the City and the Developer was doing it for the Developer – and not an engineer or a reasonable person in sight.


(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada June 22, 2021   

The nightmare of a late commission, a tight deadline, and writing an expert’s report in plain-English

I was surprised at how difficult it is to write a forensic report in plain-English for non-technical readers. It’s easy in technical-English but not so much in plain-English. Translating a foreign language – from technical to plain – is difficult.

Writing in technical-English just sails along because you’re reporting a thorough and objective investigation using words suited to the task, and there’s lots of guidance (Refs 1, 2 and 3):

  1. You identify each task – and many of these are standard tasks carried out in all forensic engineering investigations, including those when you follow-the-evidence,
  2. Describe the task,
  3. State why you did it,
  4. The data you got,
  5. Your analysis of the data,
  6. The light it shed on the cause of the failure or accident,
  7. Note how the findings of each task support, or otherwise, the findings on cause of other tasks, and,
  8. Finally, how the findings support your evolving hypothesis as to cause.

The investigation goes deep inside as you do your work. And then comes out easily when you sit down to write your report.

It’s easy to write technically because you’ve lived your investigation for days or weeks, and you’re writing for kindred souls, other technical people, in words that roll off your tongue. But, putting it in jargon-free, plain-English is another story.

A tight deadline makes writing in plain-English even more difficult. Like, you were retained months or years after the failure or accident, and the deadline is just around the corner. Nor when you get mini-briefings from your client as you write. The mini-data is good but it’s got to be analysed, checked against other data and included in the report – in plain-English.

I had all three during a forensic investigation a few months ago – late commission, tight deadline and mini-briefings. I also had non-technical readers so I decided to write in plain-English. That’s four.

I was reviewing my report weeks later after submitting it in preparation for trial and saw the odd phrase and word that I might have restated. No change in opinion just that the wording might be tweaked. I thought afterwards that I must write for the technical reader in late/early situations like this. Never mind plain-English. Too risky.

I also thought that all forensic reports should be written then put aside for a while and read again later before submitting. That’s how I draft my blogs, over a period of a good many days, or sometimes several weeks. It’s worked for blogging for nine years. It should work for forensic reports.

Forensic reports in plain-English for non-technical readers is a challenge for the writer but good for the client when you’re retained early and the deadline is way down the road. It’s bad, a nightmare, when the deadline is just around the corner.

I will continue to write my reports in plain-English but I’m alert to the difficulty – learned during the last few forensic reports I’ve written. One of these was submitted as a preliminary report because the deadline was so tight. I’ll write in plain-English because I enjoy reporting to the interface between engineering and other professions. This is also the reason I enjoy blogging on the nature and methods of forensic engineering investigation.


  1. Mangraviti, Jr., James J., Babitsky. Steven and Donovan, Nadine Nasser. How to Write an Expert Witness Report, 2nd ed., 2014, SEAK, Inc., Falmouth, MA (A massive 560 page, 1.25″ thick, 8.5″ x 11″ tomb)
  2. Zinsser, William K., On Writing Well, 7th ed., 2006, Harper Collins Publishers, New York (The best on the market for writing non-fiction. Note that it went to seven editions before the author died and sold 1.5 million copies)
  3. Nova Scotia Civil Procedure Rule 55 Governing Experts, 2010, and similar rules and codes elsewhere in the country (Hard-nosed guidance to ensure the expert reports all reasoning, including that possibly leading to a different opinion)

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada June 11, 2021   

Why do I get real good forensic aerial video in the spring, fall and winter?

I’m learning all the time about new methods of forensic investigation.  And, for my readers, hopefully increased understanding of the nature of forensic engineering investigation.  For example, aerial video from a drone of a failure or accident in the built environment has been a real eye-opener for me and my clients in recent years. (Ref. 1)

It struck me recently while walking my dogs in a forest that spring and fall are good times for taking aerial video during a forensic investigation.  Winter too before the snow falls. On a sunny day you can see through the leafless trees to the brightly lit forest floor below.  I can see my dogs off at a distance in the leafless forest why not the forest floor from above?

Even as I draft this blog I’m learning.  It occurs to me that a cloudy day would be even better – no shadows to confuse what you’re seeing on the ground.

For example: I flew over a leafless forest in the spring during a road safety assessment that included a staged road accident for the first time and got excellent aerial video.  You could see a piece of gravel the size of a golf ball from 100 feet.  The video was a dispute-resolution maker.

To be upfront with you though, it was later seeing my dogs running in the leafless forest that made me realize why I got good aerial video during the road assessment.

Another example: I had another case, a fuel oil contaminated site, that was in a dense hardwood forest that was a prime candidate for this type of aerial video.  It didn’t come to pass – the case went off on another tack – but I was ready to capture good video through a leafless forest.

Aerial video of fuel oil contaminated sites in recent years has been a game-changer for me in treeless terrain – why not in leafless terrain too?

Why am I telling you this?  Because, if you’re processing a dispute or insurance claim that involves an accident or failure in the built environment, get aerial video of the site.  If there are leafless trees on or near the site, get aloft in a hurry.  COVID-19 is no problem because it’s easy to keep your distance outdoors.


Well, it finally happened to me early this spring, a deliberately planned aerial video of a site from a drone through a leafless forest. Plus some testing of forest floor visibility through the leafless trees. I couldn’t get on site fast enough.

And, as turned out, unexpectedly finding a surface feature that added to my understanding of the cause of a problem.

The aerial video was all part of the standard terrain analysis of a site during a forensic investigation. You identify the surface features characterizing the site and how these might shed light on the cause of the problem you’re investigating.

(Terrain analysis with aerial video is also used in basic engineering design and construction. For example, a firm I was with in Australia used terrain analysis to select the initial route of a road through a jungle in Indonesia)

Terrain analysis today involves:

  1. Checking Google Earth photography of the site,
  2. Studying stereo pairs of black and white and coloured aerial photography of the site – taken from 6,000 feet up, and all we had in the past, but still useful today,
  3. Looking at topographic and surficial geology maps of the site,
  4. Walking and visually examining the surface of the site – the boots-on-the-ground task,
  5. Taking eye-level photographs of the site, and, today,
  6. Getting and studying aerial video using a drone flying at altitudes up to 400 feet.

(A little aside. If nothing else, drone photography plus eye-level photography gives you that 3D view of your site. We didn’t have that prior to drone photography – only eye-level, 2D views. I’ve hired planes to get aerial photographs of a site in the past but that was expensive and not as effective)

I did all the bulleted tasks during my deliberate investigation this spring plus set out markers – sheets of white paper on the forest floor – to check visibility. Visibility was good through the leafless trees – no surprise. I also set out red traffic cones a measured distance apart to give scale to a drone photograph.

I studied the aerial video of my client’s site and discovered a feature off the site that contributed to the problem on the site. This feature was not visible during the boots-on-the-ground task.


It’s been an exciting two years as I discovered new ways of getting the most from aerial video taken from a drone:

  • Leafless aerial video,
  • 3D photography of a site,
  • Virtual aerial video of a site
  • Staged accidents to assess road safety, and,
  • Pre-planning aerial video with Fly Litchi app + Google Earth

I’m looking forward to summer like the rest of you, and I’ll get good aerial video of my sites, but I can’t wait for fall and winter and that leafless view.

Maybe I’ll let my dogs, Lily and Rosie, run free in the leafless forest during a drone flight. They deserve a treat for alerting me to why I get good aerial video in the shoulder seasons.


  1. A Bundle of Blogs: Aerial video of insurance and forensic sites taken with cameras mounted on drones. Posted October 31, 2019

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada May 31, 2021