About admin

I am a consulting professional engineer with 38 years civil and forensic engineering investigative experience. I have worked on civil engineering projects, and forensic and insurance cases, in eastern, western and northern Canada, offshore Nova Shore, the Beaufort Sea, and overseas in the Caribbean, the U.K. and Australia. Civil engineering alters and reshapes the natural environment to provide built environment to meet the needs of mankind. Civil engineering includes the planning, design, construction and maintenance of structures making up the built environment. Examples of these structures are industrial, commercial and residential low- and high-rise buildings, also bridges, roads, dams, drainage systems, earthworks, and hydraulic works. Included is the plant and equipment in the buildings and the infra-structure servicing the buildings. Forensic Engineering investigates the cause of problems and failures with these structures as well as the cause of traffic and industrial accidents that occur in the built environment. The technical data from an investigation is used by the judicial system in determining damages. I practiced as a provincial land surveyor on Prince Edward Island, Canada before studying and practicing civil and forensic engineering.

Reliable forensic evidence from drone photography; Aerial photos from way-down-low

I continue to be excited about using drone photography during forensic investigations.  The engineer and former land surveyor in me loves the wealth of accurate data in photographs taken a few 10s to 100s of feet above a site where a structure failed or a person was hurt.

We’ve always had photogrammetry in engineering – using photographs taken from airplanes flying many 1,000s of feet above the earth to identify and measure features on the ground.- but we get more and better data from drone photos and get it quicker and cheaper.  The potential uses are something else:

Use #1: Investigating traffic accidents: An engineering colleague routinely sends a toy drone aloft, a 100 feet or so, and takes a photograph of a traffic accident site that he is reconstructing. (Ref. 1)  He sees his site from this angle right away and it guides his investigation as he does his field work.  He can also get a print of his drone photo for his engineering report..

Use #2: Conferring with clients: I conferred with a client a few months ago while both of us had a CD of aerial video of his property uploaded on our computers.  I had mailed the CD to him a few days earlier.  He commented on features on the ground relevant to my investigation of his failure.

In one case he gave the history of the ground at one location – cows drank from a former dug well there in the past – that was important in confirming the depth to the ground water beneath the site.  At the time I couldn’t quite believe what i was hearing about the cows and the dug well – there was no evidence of this when I was on site..

Use #3: Getting data on a site: I emailed a drone photograph to a client recently and asked him to identify the location of buried structures on his property.  Structures like two underground fuel oil storage tanks (USTs), – which leaked oil in the past – a drilled water well, two dug wells, a septic tank and a disposal field.  He did this then emailed the marked up photograph back to me a few hours later.  He used Paint, a program on PC computers.  It was all so quick and inexpensive.

Use #4; Getting BIG Data:: The height or altitude of the drone above the ground when a photograph was taken has always been of interest to me.  Robert Guertin, Halifax who takes my aerial video, found a program that gives a wealth of data on each photograph.  The data includes the height of the drone when the photograph was taken, angle of the photo shot below the horizon, bearing of the view with respect to North and the GPS location, all important data in forensic work.

Use #5: Getting low cost data:  I get the scale of drone photographs now from the known size of objects in the photographs.  Like the length and width of a building or the distance between the lines on a highway.  The scale of the photograph I sent to my client a few days ago that he marked up with Paint is 1″ = 40′.

I can check the scale of a drone photograph by setting out ground control before taking drone photographs, like photogrammetry-of-old.  Ground control is nothing more than points set out on the ground a known distance apart and height above sea level.  I used sheets of white paper to mark points on a site I was investigating in Cape Breton.

Use #6: Photographing hard to get at damage: I recently suggested to a firm who needed an expert that we could record the condition of a damaged wall with a drone photograph.  Later I could measure and analyse the damage in detail and get an idea of the cause – measuring like I do now of the ground but of a vertical surface rather than a horizontal surface.  No step ladders, staging, labour and lots of expensive time needed.  .

Use #7 Replacing expensive site surveys:  The drone photograph with a known scale is certain to replace the need in the future for a site survey by a land surveyor, and be far more detailed, less expensive and quicker.  Site surveys measure the size, location and elevation of objects and features on the ground.  Conventional site surveys can be time consuming and expensive.

Use #8: Seeing a site in 3D: I’m working with Robert to see if we can get a stereo pair of drone photographs of a failure site and using these to view a site in 3D like we’ve always done in photogrammetry-of-old.  Software likely exists now for viewing drone photographs in 3D.  If it’s out there we will find it and I will use it during my forensic investigations.  In the meantime we’re trying to do it ourselves.

(A stereo pair are two photographs overlapping by about 60%.  When viewed with a stereoscope – sort of like eye glasses – the site appears in 3D)

***

What more do you want from simple drone photographs?  Name it and the potential for getting it.is almost guaranteed.  Honestly, with all due respect, you or your expert would be remiss if you did not get drone photos of your site.  Your expert would not be conforming to the changing forensic investigative standard of care.

Reference   

  1.  A kid’s toy drone can photograph the site of an engineering failure, a personal injury or a traffic accident.  Posted September 12, 2018

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The two solitudes of expert services

Take your pick: An expert from the great majority represented by Ruth Corbin’s pilot study of 152 experts, or an expert from the fringe, (Refs 1 and 2)

The study found that the majority of experts know they’re serving the court, not the lawyer who retains them nor the lawyer’s client, and they continue to swear oaths to that effect.  The study was carried out because the judicial system continues to disbelieve them.

Fringe experts believe they are serving the lawyer and his client, not the judicial process.  This to the extent that some want to know upfront the technical issues as perceived by the lawyer – no mention of technical issues that the expert might identify – and how much budget money they got.  These questions during a first telephone call don’t resonate well.  I wouldn’t call these experts hired guns USA style but perhaps treading close Canadian style.

The “two solitudes” came to mind when I was chatting with one fellow and this fringe characteristic was reflected in his comments when the question of who we serve came up..  When i asked he was adamant that experts serve the lawyer not the judicial system.

Fringe example #1: Later this chap asked me to join him in responding to a lawyer’s need for an expert to investigate the cause of damage to a structure.  I didn’t think much about it at the time but he only casually referred to the lawyer by his first name as someone he knew, briefly mentioned another party involved and identified the location of the structure.

Based on my colleague’s description of the problem as he was briefed by the lawyer the cause was obvious, an easy initial hypothesis.  I had investigated this type of problem often enough over the years and it’s written up in forensic engineering guidelines on typical civil engineering failures and their cause.

i agreed to join him help resolve the dispute.  He would manage the case he said and I would investigate and confirm the cause of the problem.  He asked and I updated my CV over a weekend and sent it off to him on the Monday, only to learn he had responded to the lawyer on the Friday sans my CV but including his.

On reading his response to the lawyer I saw brief mention of my name.  When I asked he said he would send my CV when the lawyer asked for it.  I also asked several times over the next few weeks for a copy of his CV as presented and the name of the lawyer and his firm but he never gave me this information.  Months later he explained, “With deference, I’m not going to give you his name.  He called me.”.  Tricky, eh?

He’s heard nothing since from the lawyer.  I can’t help but think the lawyer’s smart enough to know my colleague’s engineering background hardly qualifies him to investigate this type of failure.

Nor can I help but think I witnessed fringe behaviour.  This chap is pleasant, well educated and experienced and I’ll consider working with him in the future, for the benefit of the judicial system, but he’s a bit tricky as I learned and we’ll get things out in the open at the get-go.

But, on second thought, I don’t know if perception is everything and I’m seen to be associating with a tricky, fringe expert.  Another forensic engineering colleague on recounting this case to him was quick to remind me of the perception issue.

Following are a few more fringe cases to ensure that you know there is a fringe solitude to expert services.

Fringe examples #2 and #3: I read two expert engineering reports by separate experts, one on the stability of a fill slope and the other on a slip and fall accident.  I cringed at the bias exhibited by the phraseology in both cases in favour of the experts’ clients.  Crass in one case.

You might say there’s a subjective element in an assessment of bias and that’s true.  But I feel more confidant in my subjective assessment after reading about the eight main biases in engineering. (Ref. 3)

I’ve also read and written a lot of engineering reports, research papers and blogs/essays over the years and I sure do know the difference between objective and biased phraseology.  Think most of us do.

I’m also comfortable with the objective evidence in both cases.  In the fill slope case, the expert did not get out of his car to see the large pieces of construction debris at the toe of the slope threatening the stability.  The debris included organic matter like tree stumps that rot away in time and cause a slope to subside a lot.

And in the case of the slip and fall accident, quite apart from his phraseology, the expert’s comments indicated he did not know the standard of care existing in the area for investigating the skid resistance of the floor at an accident site.

(Skid tests are coefficient of friction tests like in high school physics)

(A fill slope is the slope the surface of the soil or another material slumps down to when it’s piled on the ground.  A cut slope is the slope soil takes when we cut into or excavate the ground.  We see cut and fill slopes everywhere along our highways)

Fringe example #4: Would you like to know about a second slip and fall accident that exhibited fringe behaviour?  But, to cut the engineer some slack, possibly because he was new to the expert services arena.

An engineer, a five hour drive from the accident scene, decided the cause of the accident from pictures provided by his client.  He did not travel to the accident site and examine it firsthand nor carry out skid tests.  That would have added to the cost of the forensic investigation.  The judge dismissed the expert’s evidence.

Fringe example #5: Would you like a fifth fringe case; actually a fringe expert?  At least to some extent a fringe expert.  Years ago I heard an expert remark that he “…knows how to work a case up”.  Work it up into a “…juicy case…”.

Is my years-ago colleague practicing near the fringe?  Possibly.  He is good though in his area of expertise and still practising suggesting he’s impartial enough.  The last thing a lawyer wants is an expert that can be made a fool by the judicial process.  My colleague would have gone by the wayside years ago if he was a blatant fringe expert.

There’s no question the great majority of experts serve the judicial system and do this objectively.  Read Ruth Corbin’s paper again.  And it’s no secret there’s a fringe element that serve themselves.

Sadly enough, with all due respect to civil litigation lawyers, some are contributing to maintenance of the fringe solitude.

I attended the Expert Witness Forum East in Toronto in February and gave a talk on the principles governing cost control in civil litigation involving experts.  During a presentation by others I heard a lawyer suggest that experts should be retained on a contingency basis.  That suggestion has got to be out in left field considering that perception is everything in the judicial process.

The suggestion went nowhere in the ensuing discussion.  But the idea is out there and I’m sure there are fringe experts who will pick up on this idea and run with it and help maintain the “two solitudes” of expert services.

Fortunately, the judicial system is getting what it needs from the great majority of experts, whether it realizes it or not.  The fringe just muddy the waters a bit.  Still, the system has got to be on guard against the fringe experts scaling the bulwarks and taking over.  The fringe experts are out there.

References

  1. How experts are helping break the expert witness logjam.  Posted April 30, 2018 (A blog on Ruth Corbin’s  paper, following)
  2. Corbin, Ruth M., Chair, Corbin Partners Inc. and Adjunct Professor, Osgoode Hall School, Toronto, Breaking the Expert Evidence Logjam: Experts Weigh In, presented at Expert Witness Forum East, Toronto, February, 2018 (Google it)
  3. Are experts being being broadsided by bias, unbeknownst to them?  Posted April 12, 2018

 

 

 

Why did the bridge collapse in Italy and how might Advocates have known this could happen?

(There’s take-away insight in this item for Advocates at the case merit assessment stage, particularly in Appendices 1 and 2.  The simple data there plus conferring with a forensic engineer can help you assess the technical merit of a case)

***

Right away, three engineers had similar thoughts about the cause of the Morandi bridge collapse August 14 in Genoa, Italy :  My friend, Paul Gunson, Adelaide, Australia, in an email a few days ago, friend, Reg Crick, Halifax, during a chat, and me. (Ref. 1)  Paul drove under the bridge in 2009.

Take your pick of causes from a survey of these people:

  • Water,
  • QC,
  • Maintenance,
  • Water

If that’s not enough, I’ll tell you a little secret below about how designers tweak - some might skimp-on - the factor of safety.  (Actually, it’s good engineering not skimping but you need an informed public to understand that)

(QC as in Quality Control during construction and Water as in Lots of Water)

Paul did some research and found that the Morandi bridge and one other showed serious rusting of the steel reinforcing – too much water and too little maintenance  The concrete cover was spalling in some areas and exposing the steel to the weather.  There were also reports of concrete that was way below the specified strength – too little QC.

I did quite a lot of quality control of concrete and earthworks in the past and Paul’s findings resonate with me.  Quality control and maintenance are not very glamorous and often get the short end of the stick.

In a blog several years ago, I added quality control and maintenance to a list that I saw of the stages in the life cycle of a building or civil engineering work – to increase the total to 11.  There’s no questions they are stages where failure can occur.  Ignore them at your peril. (Ref. 2)

Almost the first thing Reg said when we chatted about the bridge in Italy, “Get rid of the water!! (Stupid!!)”.  Reg didn’t say “Stupid!!” but that was the tone. (Ref. 3)  He was referring to proper drainage of the water from the bridge deck that isn’t provided for during bridge design.  Drainage design isn’t very glamorous.

Reg noted another mutual friend Bill Waugh, who designed dozens of bridges in Nova Scotia and Jamaica before he passed away, despaired at the inattention to deck drainage during bridge design.  Water rusts exposed structural steel..  There’s an element of maintenance in this as well; keeping deck drains – when they are present – clear of debris so the water can drain.

I wondered when I first saw the bridge failure why successive spans of the bridge went down after the first one?  Was that continuous span of bridge deck over successive piers designed to such a low factor of safety – in the interest of looking slender and pretty – that a span relied on adjacent spans for some of it’s support?  And when one span goes down, like dominoes many go down?  But in hindsight I realized that proper design of bridges like this one might in fact rely on adjacent spans, but perhaps too much.

A tweaking engineering design secret: In engineering design the factor of safety is reduced – confidently whittled away – with increasing successful design and construction, and no failures.  Until the pendulum swings too far, failure occurs, the pendulum swings back.and the factor of safety is put back up.  This really does happen in design. (Ref. 4, pages 100, 101. A very good read)

(The factor of safety is a number got from dividing the weight you want to support safely into the greater weight that will break the thing providing the support – cause it to fail)

If you want to know more about when and where failure occurs and who is responsible – a broader picture - see Appendices 1 and 2 below.

It’ll be a while before we know why the bridge in Italy failed but the smart money is going down on over confidence during design and poor deck drainage and maintenance.  And no way can I leave out poor QC during construction.  Any takers?

***

There’s food for thought for Advocates in this item.  Buildings, civil engineering works and infrastructure fail in many ways, and some of these are an easy first pick for a forensic engineering expert at the merit assessment stage.  And failure doesn’t have to mean total collapse of a building, – or a bridge like in Italy – but simply that it doesn’t work right.  The bridge probably didn’t work right for years, like in poor deck drainage.

Poor design, construction and maintenance can also injure people, for example, in slip and fall accidents on floors with low skid resistance.

What’s the take-away for Advocates?  You’ve learned that when a failure occurs in the built environment or a person is injured experienced engineers are suspicious of what took place at certain stages in the development of a structure.  Our suspicions are backed up by independent and detailed studies by researchers in the U.S. and Europe of 100s of failures.

Taken together – our experience as engineers and these studies – we have a good idea where to look for cause.  If you don’t consult an expert at the merit assessment stage you risk technical failure of your case.  

References

  1. Personal communication, Paul Gunson, Adelaide, Australia, 2018
  2. Stages in the “life” of a structure helps communication between counsel, insurance claims managers and engineering expert. Posted July 2, 2015 (See update Appendix 1)
  3. Personal communication, Reg Crick, Halifax 2018
  4. Petroski, Henry, To Engineer is Human: The Role of Failure in Successive Design, Vintage Books, New York April 1992,
  5. International engineering magazine publishes information on foundation engineering in eastern Canada – and also information useful to counsel on the causes of failure.  Posted January 4, 2013  (See Appendix 2)

Appendix 1

(The following was taken from Reference 2 above and updated)

You might be interested in the updated list below of the stages in the “life” of a structure in the built environment.  Structures include earthworks and waterworks – a reshaping of the natural environment – as well as buildings and bridges.

I came across the basic list while reading the latest, 2012 edition of Guidelines for Forensic Engineering Practice.  I added the stages in italics to those in the Guidelines.  The list is a useful breakdown of the aging of a structure.

The Guidelines were published by the American Society of Civil Engineers (ASCE).  Civil engineering includes structural engineering and geotechnical engineering.

I see the list providing context and facilitating communication between counsel, insurance claims managers and consultants, and an engineering expert.  Failures and personal injury accidents can occur pretty well any time during the life of a structure.

Principles governing communication between counsel and expert have been developed recently by The Ontario Advocates’ Society. (Ref. 2)  The following list of stages in the life of a structure will further help counsel and an engineering expert talk to one another when a failure or personal injury accident occurs:

  1. Conceptualizing
  2. Planning
  3. Designing
  4. Constructing
  5. Quality control (during construction)
  6. Operating
  7. Maintaining
  8. Renovating
  9. Re-configuring
  10. Decommissioning
  11. Demolishing

ASCE say that, “Failure can be defined as an unacceptable difference between an actual condition or performance and the intended or reasonably anticipated condition or performance.”  This can occur during any stage in the life of a structure.

Furthermore, “Failure need not involve a complete or even partial collapse.  It may involve a less catastrophic deficiency or performance problem, such as unacceptable deformation, cracking, water- or weather-resistance, or other such phenomena.”

It’s not difficult to imagine that failure can occur at any stage.  Nor that personal injury accidents can occur at any stage.

Communication is easier for both counsel and client and counsel and engineering expert if we all have an idea of a structure’s “life” and the stages it goes through as it ages  The list above can help us.

Appendix 2

(The following was taken from Reference 5 above)

An article entitled “The expert witness and professional ethics” reports on the categorizing and classifying of the causes of structural failure as determined by researchers in the U.S. and Europe.  This research reviewed the causes of hundreds of failures.  Based on the research the primary causes of failure were categorized as follows:

  • Human failure
  • Design failure
  • Material failure
  • Extreme or unforeseen conditions or environments
  • Combinations of the above

When professional engineers were at fault (human failure) the causes of failure could be classified as follows:

  • 36%…Insufficient knowledge on the part of the engineer
  • 16%…Under estimation of influence
  • 14%…Ignorance, carelessness, negligence
  • 13%…Forgetfulness, error
  •   9%…Relying on others without sufficient control
  •   7%…Objectively unknown situation
  •   1%…Imprecise definition of responsibilities
  •   1%…Choice of bad quality
  •   3%…Other

When the percentage distribution of the failures were summarized the research found that almost half were due to errors in the planning and design of a structure and a third occurred during construction:

  • 43%…Planning and design
  • 36%…Construction
  • 16%…Use and maintenance
  •   7%…Others and multiple factors

I reviewed research a few years ago that found many, possibly most, foundation failures were due to inadequate geotechnical investigation of the foundation soils.

This type of information based on what appears to be quite exhaustive research is valuable to a forensic engineer in forming an initial hypothesis of failure at the beginning of an investigation.

The information is also valuable to Counsel in assessing whether or not to take a case or gaining an appreciation of where a forensic investigation may be leading based on initial oral reports by the professional engineer investigating the cause of the failure.

 

 

 

 

Forensic engineering and face transplanting

I was struck by the news report a few days ago about the man getting a face transplant, particularly the five years the surgeons and medical docs planned such a daunting operation. (Ref. 1) It reminded me about a case I had a while ago, albeit less difficult by comparison, and months of planning not years.  Nevertheless, I had that daunting feeling too.

Maurice Desjardins’ face was damaged by a bullet during a hunting accident.  He couldn’t close his mouth property and had holes in his face for a nose, and breathed through another hole in his windpipe.  Surgeons tried rebuilding his face with conventional plastic surgery over the years without much luck.

Then Dr. Daniel Borsuk came along, “un magician du visage” (a magician of the face), in his mid 30s and full of youthful piss and vinegar, and after five years of planning – Success.

Dr. Borsuk plus 8 other surgeons, 5 anaesthesiologists and 100 other medical, nursing and support staff performed two operations at the same time that had to end within minutes of each other.  The one operation removed the face of the brain-dead donor and the other transplanted the face before it died.

The operating rooms were so busy looking in news reports that it seemed no one moved unless they all did.  It reminded me of my smallish kitchen when five friends are in it each preparing a different course for dinner.  When one has to move to get something from the cupboard; we all have to move.

So, why am I telling you this?  How does a face transplant relate to forensic engineering?  It relates because some forensic investigations also take a lot of planning to know where you’re going.  Not years but sometimes many months and that can be scary because time is money in civil litigation.

The news report made me think of a case I’ve got that contains six different investigation, design and construction specialties.  They are as diverse as lifting a structure off its foundations and setting it aside to chasing an elusive material across a site, quite literally.

Where do I start in dealing with such a problem?  And how do I estimate the cost of the different specialties to guide the way forward when not a lot of experience exists in the area, certainly not all under one roof.  And for the one specialty, the magnitude of the problem is not known until you start chasing it.  How do you estimate the cost of something like that?

I’m getting on top of this case as the months go by, fortunately not years but still long and difficult. I had that daunting feeling when I started and was reminded of it when I saw the news report.

I thought of another case involving repair of the old foundations of a structure founded on sloping, filled ground that is still subsiding and shifting after about 40 years – not a sinkhole like in oxford, N.S. but almost equally challenging in the uncertainly that had to be confronted.  The main problem was repairing the foundation and supporting the structure safely while accommodating future ground movement and conforming to the standard of care.

Fortunately I remembered a case report from years ago about providing jacking points in the support for a structure underlain by compressible foundation soils.  I also conferred with a friend in Australia, Paul Gunson, who dealt with a similar problem beneath a railway line. (Ref. 2) Paul’s innovative solution included grout and rubber blocks for foundations.  The way forward was clearer.  Still, lots of non-textbook problems to solve and solutions to implement.

Two or three other engineering cases come to mind as i write.  It’s interesting, that the difficult, many month-long ones concern the ground and Mother nature, unknown, unforgiving quantities that don’t lend themselves to neat, quick and easy textbook solutions.  I’ve known about the tricky ground for decades and the planning that is necessary.

For certain, “the magician of the face” knew about tricky plastic surgery and that he was operating at the cutting edge of face transplanting when he started planning years ago.  A friend of mine, a retired ear, nose and throat surgeon, told about repairing a throat one time damaged by a chainsaw – a suicide attempt – and another repair, a windpipe pierced by a 2″ diameter stick.  Where do you start?

It’s a good thing that engineers and surgeons like to have a problem to fix and one to look forward to.

References

  1. Canadian Broadcasting Corporation, CBC,  and other news’ reports, week of September 9, 2018
  2. Personal communication, Paul Gunson, professional engineer, Adelaide, Australia, July 18, 2018

 

A kid’s toy drone can photograph the site of an engineering failure, a personal injury or a traffic accident

C’mon, really? It’s true, as I found out a few days ago during a meeting in Moncton.  I was told about a small drone fitted with a camera that could take vertical, aerial photographs above the site of an engineering failure, a slip and fall accident or a traffic accident and do this within Transport Canada’s regulations.  For that matter, the site of any personal injury.

I was at a meeting of CATAIR, the Canadian Association of Technical Accident Investigators and Reconstructionists.

Transport Canada’s strict regulations considers any drone weighing less than 250 grams a toy.  The Zerotech Dobby Pocket Selfie drone weighs 219 grams fitted with a battery and a 4K HD camera and costs about $350 Cdn – just a toy.  For a look-see and demonstration, Google ZEROTECH Dobby Pocket Selfie Drone FPV With 4K HD Camera  

I can imagine carrying one of these around – almost in your pocket – during a visual assessment of a site like we carry a carpenter’s tape now.  Maybe they’ll be standard issue in the future in the tool kit of forensic engineers, civil litigation lawyers, claims managers and others concerned with a site that has a problem.

The kid’s toy Dobby drone doesn’t take good quality aerial video, which I rely on during my forensic investigations – it’s not fitted with a gimbal -  but it does take inexpensive vertical photographs quickly.  These would be photographs a little like those we engineers used to take of a site from the raised bucket of an excavator or a boom truck.

(A gimbal is a device that keeps a camera level and minimizes vibration.  The basic device has been known for centuries – but it’s not on the toy Dobby because it increases the weight and cost)

Frame grabs of single photographs of the ground from good quality aerial video are easy to get like those from a toy drone but aerial video takes more time to organize and process and is more expensive.

I plan to compare the quality of vertical photographs taken with a toy drone of a site I’m investigating now to that of a frame grab from an aerial video.  I’ll wait till the leaves fall from the tree-covered site so we can see the ground better.  I’ll let you know how they compare..

Getting evidence in slip and fall accidents and building failures with video taken from a drone

I’m using drone-mounted cameras to get video of sites where people slip and fall and buildings fail.  The evidence is different, easy to get and cost effective – a few hundred dollars depending on location.  See Examples below also the References.

I take video almost exclusively because the resolution is so great in frame grabs that stills are not necessary.  Video is normally shot at 30 frames per second.  You can fly as fast or slow as you like, dip up and down, slip sideways and hover – videoing all the time.  Altitude and speed are recorded, and GPS on some drones.

There’s nothing technical about this.  You can get video with a simple, inexpensive camera fixed to a drone flying a few feet, 10s of feet or 100s of feet above and all around the site of an accident or failure.  The first aerial video I had taken was with a GoPro camera like those attached to a skier’s helmet for a scary run down a mountain.

Video from aloft is not the only means by which evidence is collected during a forensic engineering investigation.  This way, however, is relatively new, simple, cost effective and the evidence is from a different angle and sometimes quite revealing.  A DVD of the video on everyone’s laptop also enhances conference calls.

Following are some ways I’ve used video taken from a drone in recent years, or might have, and ways I may do in the future:

Example #1 Recently.What better way to survey and record defects in a high retaining wall involved in a flooding problem than from a few 10s of feet above the ground and off the face of the wall?  Example #2 Or identifying the potential location of fuel oil spilled on different properties as evident from distressed vegetation and colour changes in the ground so visible in a video taken from a few 10s of feet high?.

Example #3 A choice application would have been capturing the re-enactment of a nail gun accident on video from a few feet and right over the scene.  Unfortunately, there was no room for a drone to hover in the tiny room that was available – the actual scene was more expensive.

Example #4 My forensic investigation and re-enactment a few years ago of the John Morris Rankin accident at a test site at the Shearwater Airport would have been a perfect application of aerial video as would filming the 75 foot cliff over which John drove in Cape Breton.  As it was, I got good aerial video of the test site from a Sea King helicopter borrowed for the purpose.  I also got footage from the top of a rented boom truck.  Today I would use a drone fitted with a video camera.

Example #5 Quite recently I thought to use a drone to get video at a step-down and stumble accident site where there was lots of room to hover.

Example #6 Even more recently I’ve thought of using a drone to video the re-enactment of slip, trip and fall accidents in public places where I know there is lots of room to hover.  Places like auditoriums, sport’s facilities and airport terminals. 

You can grab frames at 1/30 second intervals from a video of a re-enactment and study slight changes in the movement of the slip and fall victim.

Techniques like these are being used now to estimate the speed of cars and airplanes in accidents.  Resolution is so good that you would be able to see the nail in a nail gun accident from 200 feet up – if there was an airport terminal with a ceiling that high.

There is also some chance that study of the condition of the floors as seen in the videos  - subtle changes in pattern, colour, texture, material or workmanship that contribute to floor skid resistance, – would cast light on the cause of the accidents.

This is like terrain analysis in civil engineering, – a well developed method – except indoors rather than outside.  The terrain’is a floor rather than the ground down hill of a fuel oil spill or along the proposed alignment of a highway.

Example #7  Also extremely valuable - surveying damage to the side of a multi-story building with a drone-mounted video camera – the former provincial land surveyor in me is enthused about this one.

Video could be taken from a distance of a few 10s of feet to document the character and extent of the damage to the wall, then from a few 10s of inches to measure the damage.  No expensive scaffolding necessary and workers climbing up and down.

Scale for measuring what is seen in the video would be got from the known size of building components used to construct the wall.  For example, the known size of a concrete block and the known thickness of the grout between concrete blocks

The character and configuration of the wall damage, and the size of cracks often points to the cause of the damage.  Random hairline cracks due to normal material shrinkage?  No worries.  Cracks that exhibit a predictable configuration and need to be grouted tell quite another story.  The cause is often almost a given, and would be one of the ways buildings fail.

Studies of how buildings fail have identified at least 209 different ways and they’ve all got causes. (Ref. 3)  And these don’t include all those involving the foundations and foundation soils – too often the Achilles’ heel of designers and builders.

***

This method – taking aerial video with drone-mounted cameras – is being used now in North America.   (It’s a new application of photogrammetry – the identification and measuring of the size of things on the earth as seen in photographs taken from the air)

Using video shot from a drone has got to be one of the most cost effective forensic engineering methods to develop in a long time.  Getting a lot of evidence quickly and cheaply is not too hard to take.

Like I said above, the savings continue when you distribute a DVD of the video to the parties involved for a conference call while each party views the scene on their laptop or device of choice.  I did this during one forensic investigation and surprisingly got more evidence still from comments made during our discussion.

With today’s technology, you can even ‘crew’ on a drone flight as ‘navigator’ by standing next to the ‘pilot’ flying the drone and direct the video to shoot from a remote display.  The video takes on more meaning when you’re part of the action.  I also end all my videos with footage of the pilot and myself, sometimes the plaintiff, standing on the site so there’s no question we were there.

References

  1. A picture’s worth a 1000 words, possibly many 1000s in forensic engineering with a new aerial photographic technique. Posted January 15, 2014 (see aerial photographs from a drone flight in this blog)
  2. New forensic aerial photographic method proving extremely valuable. Posted January 30, 2014
  3. How many ways can a building fail, and possibly result in civil litigation or an insurance claim? Posted July 10, 2014
  4. Forensic photography – the expertise available in eastern Canada. Posted February 26, 2015
  5. Fixed wing drones – another tool in forensic engineering investigation. Posted November 4, 2015
  6. “Crewing” on a forensic drone flight. Posted October 4, 2016
  7. Getting evidence with a low cost, low tech drone flight over a forensic site. Posted March 31, 2017
  8. Conference call on a “drone flight” reduces cost of civil litigation. Posted May 18, 2017
  9. “Unexpected” evidence and the importance of drone photography in forensic investigation. Posted July 19, 2017
  10. Drone video as a forensic technique is joined by drone photography as an art form. Posted August 2, 2017

How to avoid ‘surgery’ during a forensic investigation

Recent news coverage of archaeologists investigating the ground got me thinking about using their method in forensic investigation.  It’s called ground penetrating radar, GPR for short.  It sounds technical but it’s not really.  It’s simply a radio transmitter and a receiver.

The device sends radio waves into the ground, processes their reflection from a buried object and displays the results on a computer monitor.  The display is analysed and the nature and depth of the object is determined.  Airports send radio waves out all the time to identify your inbound flight from Toronto and how near you are to landing.

GPR is used to look for objects of interest below the ground surface.  Things like old skating rinks, stone walls and graves as reported in the news stories on archaeological work at the Halifax Commons and Grand Pre in Nova Scotia and at Sydney Mines in Cape Breton. (Refs 1 and 2)  The work on the mainland is by Jonathan Fowler, Saint Mary’s University and in Cape Breton by Maura McKeough, Parks Canada.  GPR can also be used to identify the depth to the water table, different layers of soil and rock and voids in the ground.

There was a news report a while ago about a house in Nova Scotia collapsing into a void.  GPR could be used to locate voids like this before a house was built.

i used GPR during an engineering investigation in the Bahamas looking for voids in the limestone beneath an airport runway.  The voids are called banana holes.  I understand they got this name because banana plants grow there when the roof of the void collapses exposing it at the surface of the ground, or a runway.  The voids form when ground water dissolves the limestone.

You can imagine the civil litigation that would result if an aircraft on landing caused the roof of a banana hole to collapse and the aircraft to crash.  Particularly considering the ready availability of remote sensing methods like GPR to locate voids.

These methods are remote sensing – non intrusive – like CAT scans, X-rays and Ultrasound in medicine.  No surgical cutting a patient ‘s body to see the tumor and no digging in the ground to see the void.

On a personal note, my re-awakened interest in this method was also its possible use in locating the unmarked grave of my baby sister in a cemetery in New Brunswick.  My mother had a 7.5 month premature baby – Baby Hazel – who died 2.5 days after she was born.  My sister’s casket would display on a GPR monitor as an unusual feature in the soil.

I don’t know when the need to use GPR during a forensic investigation will arise but I’m certain it will.  I can imagine it resulting in a more cost effective forensic investigation in some instances as well.  Almost any civil litigation involving the ground might be a candidate.

i chanced to see a drone fitted with a camera taking low level, aerial video several years ago and now consider getting aerial video with a drone of all my forensic sites involving the ground.  Who knows when and where ground penetrating radar, GPR, might be useful during a forensic investigation?

References

  1. Fowler, Jonathan, professor of archaeology at Saint Mary’s University, Halifax, NS as reported in The Chronicle Herald, Halifax, Saturday, July 18, 2018
  2. McKeough, Maura, cultural resource manager, Parks Canada as reported by CBC June 29, 2018

Why do I blog? – See a few good, perhaps one or two surprising reasons in the following

During the past six years, I blogged to help you gain some understanding of the nature and methods of forensic engineering in the event you may need an expert.  Just so you know something about the services you’re retaining.  See Earlier Blog Update below for quite a good read

I also like to write.  I belong to a group that could be characterized as a story-writing and story-telling group.  Reporting on a forensic investigation is like telling the story of the investigation; a good way of explaining it to the judicial system.

But I’ve realized the last couple of years that striving to write expert reports and blogs well trains me in another way: To think and analyse on paper, draw conclusions and formulate an opinion on the cause of an engineering failure or personal injury.  Then document the investigation and results in a well-written expert’s report.

Like last year, when drafting this annual Why? blog, I’m now in the middle of an investigation and the fixing of a problem that is benefiting from thinking-on-paper.  In this case it’s a non-textbook problem in the extreme – underpinning a structure founded on an old, rubble fill that was quite unstable in the past and still is a little.  I’m also giving much thought to the standard of care – what would my peers have to say about fixing a problem like this?  I doubt there’s much relevant experience in the Atlantic provinces.  Also like last year, the fixing will go on for a while yet as I turn the situation and the data over in my head and squeeze out the way forward on “paper” – the word processor..

There’s a lot implied in the words forensic engineering and a lot of writing is involved at some stages:

  • Investigate the cause of a failure or accident
  • Examine and observe
  • Do a subjective assessment (like in the SOAP procedure in medicine)
  • Measure and test
  • Research
  • Analyse data
  • Do an objective assessment
  • Draw conclusions
  • Determine cause
  • Formulate an opinion
  • Present reliable evidence to counsel and the court or tribunal in simple, non-technical English verbally and in well written experts’ reports

(Like lawyers, experts don’t write a report and walk into court or a tribunal without a lot of investigation and preparation beforehand. After Ref. 1)

Reaping the benefits of writing/blogging is not unique to me nor is it new.  Journalizing in some form as a means of working things out – your thoughts, drafting a talk, a preliminary report, noting an item to remember - has been around a long time.  I carry a notebook with me most times, like I’m sure many of you, to capture a thought along the way.

It’s just that it’s not so very technical-sounding – thinking-on-paper - even though it has an important role in the different stages of forensic investigation.  I like to think, “I knew that!”, the benefits, but the penny has dropped several times in the last two or three years and made a louder noise each time.  It’s a nice thought, that I’m thinking-on-paper when I’m blogging, and learning and having fun doing it.

References

  1. Pizzo, Ron, Pink Larkin, Lawyers, Halifax, Wrongful Dismissal Primer: What to Know When an Aggrieved Employee Walks Into Your Office.  APTLA Conference, Halifax, November, 2016

***

Earlier Blog Update: Why do I blog on forensic engineering investigation?  Posted July 22, 2016

I blog because I want you to know about an interesting field of engineering that I enjoy and that contributes to the resolution of disputes - a nice way to practice.  Also, an engineering practice that is relevant to the field of practice of many of you.

To some extent, ours is a litigious society and one with a lot of insurance claims involving engineering failure and personal injury.  Inherent in this situation are technical obligations for counsel and their need to know something about forensic investigation.  Some cases don’t go forward or claims settle until the technical issues are identified and investigated by an expert.

In many cases, an important duty for counsel is ensuring the technical evidence is properly understood by the court or tribunal. (See the Comment on Reason #1 below, also Ref. 1) There are other reasons I blog – I’ve identified and listed eight (8) below – but this is an important one.

I identified the following reasons by reflecting on the 174 blogs that I’ve posted in the last few years.

Why do I blog?

Reason #1 I want to describe the nature and methods of forensic investigation for counsel and insurance claim consultants, to help you understand what forensic engineers do.  Included are some of the newer methods like a low flying drone fitted with a camera to photograph the scene of an engineering failure or personal injury.

(An aerial photograph taken from a low flying drone was key to assessing the pattern of drainage at a contaminated site.  I was surprised at what I saw.  Aerial photographs of a another site is helping me assess if the site is contaminated decades after a spill)

I want to describe how we carry out independent investigations, observe, analyse, draw conclusions and formulate objective opinions.  Then present reliable evidence to counsel and the court or tribunal in simple, non-technical English.

Comment: Why is this a particularly good reason?  It’s because I’ve learned that counsel has obligations with respect to the expert’s report or affidavit. (Ref. 1)

In many cases, counsel must learn about the technical subject to which the evidence relates in order to identify the relevant technical issues.  He or she has an important duty in the presentation of technical evidence to ensure it’s properly understood by the court or tribunal. (Ref. 1)

Counsel also has an obligation to monitor the cost of civil litigation in view of the often small to medium size-sized cases in the Atlantic provinces – and their sometimes less affluent nature.  This is because the extent and cost of an all-stages forensic investigation is often similar regardless of whether the engineering failure or personal injury is small, medium-sized or catastrophic.

Costs can be controlled to some extent by how an expert is retained and how early.  There are at least eight (8) different ways of retaining an expert. (Ref. 2)

It’s difficult for counsel to carry out their obligations to the court or tribunal and also monitor costs without some understanding of how experts work.

Reason #2 I also want to help readers understand why a forensic engineering investigation can be expensive.

Comment: The expense has everything to do with carrying out a thorough investigation and rendering a reliable opinion, as expected of the expert by the court or tribunal.  For certain, following routine investigative procedures in an effort to ensure no stone is left unturned. (Ref. 3)

As well, we don’t know when we start what we’re going to find that we must investigate.  Every failure and accident is different. (Refs 4, 5 and 6)  And then there are the surprise, follow-up investigations.  Not enough time and money is no excuse if we miss something.

Counsel can assist – with some understanding of forensic work - by identifying and selecting the relevant technical issues early in the case with the assistance of the expert.

Reason #3 To help counsel understand the importance of retaining an expert early in all cases, affluent and less affluent alike, the different ways an expert can be retained and the importance of monitoring costs – starting when the merits of a potential case are being assessed. (Refs 7, 8)

Comment: At present, experts are too often retained months or years after a case is taken and after the cost of the forensic investigation has been estimated by other than the expert.  This is contrary to the advice of some of the most senior members of the legal profession. (Ref. 9)

For example, I was retained by counsel 11 years after a personal injury.  I visually examined the site and reported on what could have been done to prevent the accident.  The case settled four (4) months later.  To give counsel credit, he instructed me on the relevant technical issues which reduced the cost in this case.  This type of instruction doesn’t happen very often.

Reason #4 To help the justice system understand what they should be getting for the money spent on forensic investigation: That is, thorough investigations to ensure the quality of the evidence and the reliability of an expert’s opinion, and well written reports.

Comment: Rules governing experts have placed greater emphasis on the investigation and the expert’s report, to encourage the settlement of cases without going to discovery and trial.  There are excellent guidelines on forensic investigation and also on writing an expert’s report.  And excellent books, in general, on writing well.  I’m not sure these are being consulted to the extent they should.  I recently saw poorly written reports by a forensic firm claiming to have 18 different experts on staff, so said the owner.

Reason #5 I want to understand the forensic engineering field better myself, to learn by writing the blogs and thinking-on-paper – particularly, on how addressing the technical issues supports the resolution of disputes.

Comment: Like all of us, I’m learning all the time.  Most recently about the value of low cost, initial hypotheses on the cause of problems based on very limited data.  This task could save counsel money – as long as it’s remembered they are initial hypotheses.

For example, I hypothesized with considerable confidence on the cause of a catastrophic bridge failure during construction (Edmonton) - based on study of photographs in a newspaper.  In another, the cause of the sloping, sagging floors in a multi-story building (Halifax) - based on a visual examination of the floors and knowing how buildings are constructed.

Cases are also being settled today based on simple verbal reports after the technical issues are addressed.  In some cases not even a verbal report because counsel is on site and sees the results of the expert’s investigation unfold before his eyes.

Reason #6 I want to increase my understanding of the civil litigation process.

Comment: Experts have a duty to acquire some understanding of the process.  The justice system expects this of us.

I researched and posted 10 blogs on the role of a professional engineer in the civil litigation process for the benefit of counsel and their clients. (Ref. 8) I learned a lot during this research.  I was assisted by senior counsel in preparing drafts of two of these blogs.

It’s also been an eye-opener to learn of the dichotomy between the claimant’s right to justice and the expense of getting it.  Associated is the conflicting interests of the different parties to the process.

For example, the court, while encouraging counsel to expedite cases and control costs, wants good evidence and a reliable opinion – which takes time and money.  The expert needs to do thorough investigative work to get this evidence.  He expects to get paid according to his schedule of fees, his level of expertise and the responsibility he bears.  If the claimant has retained the expert on a fee basis, he doesn’t want to spend any more than necessary.  If counsel has taken the case on a contingency basis and retained the expert, he wants to protect the worth of the file to his firm.  Quite a mix of interests.

Reason #7 Because of a sense of obligation to my readers who have seen the blog for six years now and perhaps have come to expect it – to fill a void that was there.

Comment: Feed back suggests you do get something from my descriptions of the nature and methods of forensic engineering, and my comments on related matters.

A senior lawyer in Atlantic Canada said, “I love that stuff..!!”.  Another senior legal chap on the east coast commented, “…like reading them.”  And an insurance claims consultant said, “I read every one”.  It’s hard to beat testimonials like that.

I mentioned above that two senior counsel helped me with two of the blogs on the role of professional engineers in the civil litigation process – critiqued them before their posting.  One of these noted that experts are invaluable to civil litigation.

A fellow who blogs on business ethics, Dr. Chris MacDonald, Toronto, and has an international reputation in his field – Chris is on a list of 100 influential business people that includes Barack Obama - saw fit to advise his twitter followers of my blog.

A monthly periodical on engineering construction – with an international distribution of 10,000, sought permission to publish one of my blogs.  The issue had a forensic engineering theme.  Then they came back a couple of weeks later requesting permission to publish two additional blogs in the same issue.

In six years, only about 10 readers requested removal from my distribution list.  This was because they were retired or the subject did not relate to their field of practice.

Overall, quite a good reception – suggesting there was a void, and that I`m making a contribution to the civil litigation process and to insurance claims management.

Reason #8 For that satisfied feeling that comes from creating something – a piece of literature that did not exist before

Comment: A few months after I started blogging in June, 2012, I noticed a feeling of satisfaction after posting an item, a mild elation.  It was subtle but there.  On reflection, I realized I felt good because I had created something – a piece of literature that didn’t exist until I put pen to paper.  So, I blog for that satisfied, creative feeling.  You all know how elusive that feeling is in our busy work-life, balance-challenged lives.

On further reflection, I realized the feeling was also about finally publishing information on a topic or technical issue useful to my readers – finally letting it go.  I like my blogs to be as clear and well written as possible - in a sense, like well written, mini, expert reports.

References

  1. The Advocates` Society, Toronto, Ontario, Principles governing communicating with testifying experts June, 2014
  2. Peer review costs can be controlled.  Posted January 22, 2016
  3. Steps in the forensic engineering investigative process with an appendix on cost.  Posted July 15, 2013
  4. What do forensic engineers investigate in Atlantic Canada.  Posted October 9, 2014
  5. Forensic engineering practice in Eastern Canada.  Posted May 7, 2015
  6. How many ways can a building fail and possibly result in civil litigation or an insurance claim?  Posted July 10, 2014
  7. The role of a professional engineer in counsel’s decision to take a case.  Posted June 26, 2012
  8. A bundle of blogs: A civil litigation resource list on how to use forensic engineering experts.  Posted November 20, 2013
  9. Stockwood, Q.C., David, Civil Litigation: A Practical Handbook, 5th ed., 2004, Thomson Carlswell

 

 

Update: How I was tyrannized by the obvious during an engineering investigation

Who would have known that condensation was the real cause of the flooding in a furnace room – or so it seems now.  But don’t hold your breath at the rate this saga is unfolding.  Also note that forensic investigations can go off the rails like this too.

I blogged earlier (see below) on how I investigated the cause of flood water on a furnace room floor in a vet clinic and how I concluded it was obviously due to a high water table beneath the building.  Also how I was told later that it was really due to a burst water pipe in the washroom adjacent the furnace room after staff went there and saw water on the washroom floor.

The story could have ended there with me learning a valuable lesson, that if it seems obvious keep on investigating.  But it didn’t; my lesson continued a few days later.

Vet clinic staff called a plumber about the ‘burst pipe’, he came and investigated, saw the water on the washroom floor, looked for a burst pipe but found none.  He then looked in the washroom on the floor above.  Still no burst pipe but he did find water on the surface of the cold water pipes in the washroom.  The water was dripping on the floor and in turn on the washroom floor below next to the furnace room.

Water vapor in the moist washroom air had condensed on the cold water pipes.  This would be the same as vapor condensing on the inside of a window in the winter and water running down the window.  We’ve all seen that I’m sure.

So, the flood water in the furnace room was caused by condensation on cold water pipes, not by a burst pipe and not by a high water table.

To take inspiration from a quote by Hunter S. Thompson, “Wow! What a lesson!”. (Ref. 1)  I’ll keep you posted in the event there are more chapters in the saga.

You might ask, what’s this got to do with forensic engineering investigation?  It’s a reminder, that if being thorough in the investigation of water on a floor in a small room in an old building is important, it’s light years more important for the simplest of forensic investigations.

Reference

  1. Thompson, Hunter S., “Life is not a journey to the grave with the intention to arrive safely in a pretty and well preserved body: but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming “Wow! What a ride!”. (As cited recently at the celebration of a friend’s life)

***

Earlier Blog: How I was tyrannized by the obvious during an engineering investigation

It can happen to any of us, and it finally did to me.  I was tyrannized by the obvious when investigating the cause of flooding in a large, three story building.

A building renovator called me after water was seen on the furnace room floor by staff of a veterinary practice.  They had gone to the room where materials were stored and saw a few millimetres of water on the floor.  Not a lot but still.

The renovator said the building, which was erected in the 1960s, was on a concrete, ground-floor slab, on low land and near a lake.  The furnace room was enclosed by concrete block walls.  The flood water had pooled on the slab.  He estimated that the concrete floor slab was about five feet above the nearby lake surface.

When i went to examine the site I saw that the five feet was about right and that the furnace room was an estimated 50 feet from the lake shore.  I was also told that the lake level was higher than normal due to a lot of rain this spring.

The grounds around the building sloped down slightly to the lake shore.  The front and right side of the building were paved.  There was a lawn at the back and an old paved boat ramp on the left.  The surface of the boat ramp was bumpy after many years.

The corners of the furnace room were still wet where the concrete block walls rested on the concrete floor.

I had a good look around then walked across the floors of the different rooms in the practice.  They were a little uneven which wasn’t so unusual for an old building.  But my look around wasn’t as good as it might have been and I neglected to look in the small room adjacent the furnace room.

My examination complete I met with the owner and the renovator.  I noted how the water rises in a lake during frequent rain storms.  It also rises in dug wells.  The water in a well is the water table. The surface of the water table in the ground near a lake shore is usually higher than the lake.  There is also water in the soil above the water table due to capillary action – this is when water rises in the small voids in the soil above the water table (Check high school physics)

This higher water table plus some surface water runoff across the asphalt at the side of the building could explain the presence of the water in the furnace room.  It was obvious.  I mean, the building was so close to the lake with high water levels not seen in recent years and the furnace room floor was near the lake surface and the water table.

The irregular boat ramp was typical of frost heave due to water in the ground – a high water table and capillary action during wet springs over the years – and would back up this obvious conclusion further.

I talked about different ways of preventing water getting into the furnace room.  These included the obvious – terrible word – better perimeter footing drains and/or a sump pump.in the furnace room.  A sump pump is a pump in a depression or hole in the ground – a sump.

The sump pump was decided on as the least expensive and one that could be constructed several feet below the water table to draw it down below the furnace floor.  That decision was left with the building renovator.

I left the site after about an hour – an efficient examination and consultation, or a  hurried one?

A few hours later the renovator called to explain that a staff member had gone in the wash room – the one room I hadn’t gone in – adjacent the furnace room and found a burst water pipe, the real cause of the flood in the furnace room.

I was tyrannized by the obvious and guilty of expectation bias.  The moral of the story?  If it’s obvious, keep on truckin’ and do more investigation.

How I was tyrannized by the obvious during an engineering investigation

It can happen to any of us, and it finally did to me.  I was tyrannized by the obvious when investigating the cause of flooding in a large, three story building.

A building renovator called me after water was seen on the furnace room floor by staff of a veterinary practice.  They had gone to the room where materials were stored and saw a few millimetres of water on the floor.  Not a lot but still.

The renovator said the building which was erected in the 1960s was on a concrete, ground-floor slab, on low land and near a lake.  The furnace room was enclosed by concrete block walls.  The flood water had pooled on the slab.  He estimated that the concrete floor slab was about five feet above the nearby lake surface.

When i went to examine the site I saw that the five feet was about right and that the furnace room was an estimated 50 feet from the lake shore.  I was also told that the lake level was higher than normal due to a lot of rain this spring.

The grounds around the building sloped down slightly to the lake shore.  The front and right side of the building were paved.  There was a lawn at the back and an old paved boat ramp on the left.  The surface of the boat ramp was bumpy after many years.

The corners of the furnace room were still wet where the concrete block walls rested on the concrete floor.

I had a good look around then walked across the floors of the different rooms in the practice.  They were a little uneven which wasn’t so unusual for an old building.  But my look around wasn’t as good as it might have been and I neglected to look in the small room adjacent the furnace room.

My examination complete I met with the owner and the renovator.  I noted how the water rises in a lake during frequent rain storms.  It also rises in dug wells.  The water in a well is the water table. The surface of the water table in the ground near a lake shore is usually higher than the lake.  There is also water in the soil above the water table due to capillary action – this is when water rises in the small voids in the soil above the water table (Check high school physics)

This higher water table plus some surface water runoff across the asphalt at the side of the building could explain the presence of the water in the furnace room.  It was obvious.  I mean, the building was so close to the lake with high water levels not seen in recent years and the furnace room floor was near the lake surface and the water table.

The irregular boat ramp was typical of frost heave due to water in the ground – a high water table and capillary action during wet springs over the years – and would back up this obvious conclusion further.

I talked about different ways of preventing water getting into the furnace room.  These included the obvious – terrible word – better perimeter footing drains and/or a sump pump.in the furnace room.  A sump pump is a pump in a depression or hole in the ground – a sump.

The sump pump was decided on as the least expensive and one that could be constructed several feet below the water table to draw it down below the furnace floor.  That decision was left with the building renovator.

I left the site after about an hour – an efficient examination and consultation, or a  hurried one?

A few hours later the renovator called to explain that a staff member had gone in the wash room – the one room I hadn’t gone in – adjacent the furnace room and found a burst water pipe, the real cause of the flood in the furnace room.

I was tyrannized by the obvious and guilty of expectation bias.  The moral of the story?  If it’s obvious, keep on truckin’ and do more investigation.