I mentioned in a previous blog how an expert’s investigation relies on Observation compared to laboratory and field testing. (Refs 1, 2) That blog described an investigation that contained many examples of observation and no examples of lab and field testing.

The following investigation contained many examples of laboratory and field testing – I will spare you the eye-glazing-over details – and one main observation that showed up at the end.

***

I was retained to investigate the cause of a fuel oil contaminated site in Cape Breton. It was an old spill from a fuel oil delivery truck that resulted in the evacuation of a home because of the fumes. A business on the property was also closed. The site was in a rural area on ground sloping down to a small lake.

Main question: Where did the fuel oil go?

The main question was the extent of the contamination – how far did the oil flow from the spill location. This involved sampling the soil at a number of locations beneath the house and testing for oil in a laboratory. This work found the limits of the contamination just beyond the house.

Previous work by others concluded that the ground beneath the business was not contaminated. This was based on one laboratory test of a sample of the ground some distance downhill of the business and excavation of contaminated soil at the spill location just uphill. This was forensic investigation light in my opinion – an observation.

Fuel oil rides along quite nicely on the surface of groundwater. This means that the depth to the groundwater and where it flows are important in cleaning up a contaminated site. I knew that the water table was at the lake surface and usually rose with the ground beyond a lake. But what depth was it at the spill site?

A topographic map of the area suggested that the groundwater was within 5 to 8 feet of the ground surface just uphill of the business. This was my subjective assessment, an observation after doing this kind of engineering work for years.

The owners of the property said later that the water in an old dug well just downhill of the business was at the ground surface so cows could drink there in the past. This reinforced my assessment of the depth of the groundwater at the spill site. Also that fuel oil contaminated the cow’s drinking water in the past downhill of the business and likely the soil beneath the business.

Tidying up

By way of tidying up and finishing my forensic investigation, I arranged for drone video of the site for record purposes. It also facilitated telephone discussion of my forensic investigation with my client – sort of like Zoom meetings today. I was taking this kind of video of all my sites by this time then distributing copies of the video to my client and interested parties. Sometimes these videos contained surprises at the end of the day, as you will see below.

I had the drone pilot sweep across the site at an altitude of 300 to 400 feet on the four points of the compass for the big picture then low at several 10s of feet over points of interest.

Studying the video later I was surprised to see a tongue of dark soil extending from beneath the rear of the business down hill beyond the cow’s water well. This indicated that the groundwater was at a shallow depth and that the soil beneath the business was probably contaminated with fuel oil. Also, that the test location by others was beyond the contaminated area. This was my main, almost single Observation during this forensic investigation – Example #2 – compared to many Observations in Example #1.

References

1. Observational Method: Example #1 Posted July 31, 2023
2. One forensic observation does not a cause make. Posted July 18, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, August 29, 2023. ejorden@eastlink.ca)  

I blogged on the extent to which an expert’s investigation of cause relies on Observation compared to laboratory and field testing. (Ref. 1) An example like the following will help understand this – a surprise observation at the end made it an enlightening investigation too. The observations are italicized in the following.

***

I was retained to determine the cause of water on the floor of a finished basement of a commercial building in Halifax. It was only a mini-flood but dangerous because the water was running down a basement wall, at the location of the electric supply to the building, and into an electric room.

The mini-flood, water problem

I was told by the owners and subsequently saw that the water appeared on the floor of the electric room, and a conference room beyond, a couple of hours after a rain storm started. I also saw that the mini-flooding occurred during a rain storm blowing hard out of the southeast over a long, exposed fetch.

I did the usual starting with the big picture by learning how the building was constructed including all sources of water on the roof and how these were drained.

I then removed the gyproc wall in the electric room to expose the top of the concrete basement wall and a circular plug of concrete near the top. I saw that the power supply cable was enclosed in the plug of concrete. I also saw on a wet day water seeping from the bottom of the plug down the concrete basement wall to the floor of the electric room. As the rain storm continued the wetness at the bottom of plug crept up the plug and the flow of water to the floor increased.

Power supply design and construction

I checked on the outside of the building and saw that the power supply cable to the building was enclosed in a 4″ diameter PVC pipe down the outside of the building then horizontally into the electric room. The electric cable from the street entered the top of the PVC pipe beneath a canopy after curving down then back up to form a drip-loop. The horizontal pipe was enclosed in a plug of concrete where it passed through the basement wall near the top. This was the same construction seen behind the gyproc wall inside the building.

This was a typical power supply construction for a building. You see it often, even on houses. Cable sizes, PVC pipe size and length of drip-loops vary but the basic design is the same.

I spoke with the electrical engineers who designed this installation and learned it was constructed in 2004. There was nothing unusual about the design.

I also visited and spoke with the company that sells this type of PVC pipe for electric services. There was nothing unusual about the pipe; longer lengths for the side of a building and shorter pieces for the horizontal section into the electrical room. An elbow-shaped piece connects the vertical PVC to the horizontal. The shorter horizontal piece had a cap bolted on at the elbow. It provided access to the inside of the section of the PVC pipe where the cable changed from vertical to horizontal and into the building.

Chasing down the water’s path

I removed the cap at one point and saw the cable in the pipe. I was surprised to see sediment on the invert of the elbow and staining a couple of inches up the sides of the pipe. There were also small holes in the invert of the horizontal section of pipe plugged with the sediment – these holes did not appear in the pipe that I saw at the PVC pipe vendor.

The space between the cable and the inside of the PVC pipe was tightly caulked at one time but movement of the cable as it expanded and contracted with the air temperature opened up space between the cable and the caulking over time. I can imagine heat from the electric cable contributed.

Conclusion

So, I concluded, rain water was getting into the vertical PVC pipe, then down the pipe and along the horizontal section to the inside of the building. This was expected during design of the electric service as evident from the drain holes in the invert and the caulking around the cable. This was the water I saw when we removed the gyproc wall inside the electric room. The water would have drained away to the outside of the building at one time but the holes in the invert were now plugged with sediment.

Conclusion

So, how did the rain water get past the drip-loops? I thought about this and concluded up-gusts of the rain-soaked wind were the culprit. We occasionally see these up-gusts in rain and snow storms. And, like said above, water was appearing on the electric room floor during hard blows out of the southeast, a wet point of the compass Down East.

I had my well substantiated cause – based on observations – and reported to my client as found above. There were a number of observations during my investigation and mini-conclusions along the way but I was confidant and went on my way after submitting my report.

Note: The foregoing forensic investigation was based on observation alone – no laboratory or field testing to be seen anywhere.

***

A surprise, irrefutable, clinching observation

Months later in April I ended up in hospital for a common mini-medical problem. I was on the fourth floor looking out the window at the roof of an adjacent two story building with a number of chimneys and vent pipes. And there were the up-gusts in the wind around each pipe. They were evident because moisture in the warm air was condensing in the cool April air on discharge from the pipes. The same kind of up-gusts I hypothesized about months earlier at the mini-flood building.

References

1. One forensic observation does not a cause make. Posted July 18, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, July 31, 2023. ejorden@eastlink.ca)   

The word empirical keeps coming back to me after posting a recent blog about the importance of peer review in forensic work. (Refs 1, 2 and 3) This because many forensic engineering investigations of failures and accidents in the built and natural environments are empirical in nature. Meaning, they are based on observation or experience not laboratory and field testing.

The Observational Method – or Empirical Method, if you like – is widely used and accepted in both the theoretical and applied sciences. Check out Dr. Google:

• Civil, geotechnical and environmental engineering. The OM method is particularly valuable in geotech work because the engineering properties of the ground can change with every step.
• Design and construction
• Forensic investigation
• Criminal investigation
• Psychology
• Child development
• Anthropology
• Marketing
• Statistics

What needs to be understood is that, in general, one forensic observation is insufficient in determining cause. Cross checking is essential. Several observations must be made and a number of these – the preponderance – must point to the probable cause of a failure or accident. If this is not done, peer review will flush out the fault.

In general, the Observation Method, regardless the field of practice, like in the above list, involves:

• Preparing a preliminary design or investigation based on what is known at the time. This could be of an engineering structure or the forensic investigation of the failure of one, a research study, treatment of a PTSD patient, etc. – anything where there are unknowns.
• Preparing a monitoring plan to verify, for example, that the forensic investigation or research study is yielding expected data or findings.
• Preparing a contingency plan that is put into operation if the data or findings are not within defined limits. For example, if the preliminary design is of an engineering structure, and different foundation soil conditions are found during excavation, a contingency plan might require deep piled foundations rather than shallow ones. Or, the initial findings of a forensic investigation are incompatible with the initial hypothesis of the cause of a failure or accident, then the hypothesis is modified and additional investigation is done.

Getting back to empirical, I don’t remember the last time that I did a forensic investigation that was based on laboratory testing. Field testing, yes, plus lots of observation and experience. Testing like the re-enacting of accidents, testing the layout of a highway design, or field testing the properties of materials used in construction. There’s one field test I do – 10 times in each of three (3) different directions.

Why is talk about observation and experience, and peer review, important? Because forensic engineering investigations based on the Observation Method – many are – are best served when a peer review is carried out on completion of the investigation. Better a peer review than a rebuttal review if dispute resolution or insurance claims adjustment is not reached on the court house steps.

References

1. How are forest fires and earthquakes similar, and what can experts learn from them about the importance of peer review? Posted June 27, 2023
2. Update: A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted April 28, 2021
3. A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted November 29, 2019 There are seven (7) good reads on peer review in this blog including the two (2) in the Update

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, July 18, 2023. ejorden@eastlink.ca)   

Why are earthquakes and forest fires important to dispute resolution? For that matter, all the problems in the natural environment? (See a list of examples below)

(The natural environment is everywhere beneath our feet, also what we see beyond the built environment – the concrete jungle – and what falls from the sky above)

Forest fires and the like are important because they remind us about the importance of peer review – getting your forensic work checked by another.

Predicting when these natural events will occur relies on empirical science – observations – rather than on theoretical science that is backed up by laboratory and field testing. Determining the cause of failures and accidents in the natural environment also depends on observations.

If peer review is important in theoretical science – and it is as evident in the research papers – then peer review is even more important in empirical science, implicit in forensic investigation.

Our observations are particularly susceptible to direct- and cross-examination in dispute resolution. So, in disputes involving accidents and failures in the natural environment, you’re wise if you get your work peer reviewed before being exposed to examination.

A timely example of sorts would be a forest fire. Predicting if one might occur in an area requires observing and measuring quantities like:

• Wind
• Temperature
• Humidity
• Forest type
• Ground cover

Then putting this data in a computer model, cranking the handle and getting the Fire Weather Index about whether or not conditions are ripe for a forest fire. (Ref. 1)

We still need a lightning-strike or a camp fire to ignite the ready aye ready forest. But, the ripeness of the forest is determined by observations – empirical data – and reflected in the Fire Weather Index.

In addition to forest fires – some of those in Alberta are thought to have been deliberately set – examples could also be taken from the forensic investigation of the following. All of which are dependent to some extent on observations, not just theoretical science. And all would benefit from peer review:

• Sink hole development
• Foundation settlement/subsidence
• Slip, trip and fall accidents
• Motor vehicle accidents
• Landslides
• Soil erosion and sedimentation of lakes
• Coastal erosion, and
• Flooding

***

I realized the above when I took in a lecture on predicting when and where earthquakes occur. The lecturer was Dr. Steve Kramer a geotechnical earthquake engineer from the U. S. of A. on a cross Canada lecture tour. (Ref. 2)

He explained a model – a complicated equation – that he had developed to predict earthquakes. Empirical observations were fed into the model and the prediction made.

His talk was hard to understand and I’m still working on it. But I recognize – at least so far – that his model relied on empirical science, the kind that is checked by observations not just laboratory and field tests. This is the same for disputes arising from failures and accidents in the natural environment as compared to the built environment.

What’s in this blog for a forensic expert? S/he would do well to understand that if there’s a dispute, and the problem is in the natural environment, there’s an argument for getting their investigation peer reviewed. Their problem shares common elements with forest fires and earthquakes – an empirical, observational approach to a solution.

References

1. Personal consultation with David Wagener, Stanley, New Brunswick, Canada, a forest fire fighter for 10 years with Parks Canada, retired, June, 2023
2. Kramer, Steve, PhD, Professor Emeritus, University of Washington, Canadian Geotechnical Society, 2023 Cross Canada lecture tour: Performance-based design for soil liquefaction June, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, June 27, 2023. ejorden@eastlink.ca)   

What should I do about accident and injury-prone defects I see in the built environment? For the most part, tiny defects like the following:

1. Old stairs down to a sloping sidewalk from the main entrance of an old church. The stairs have been in place for many decades. I’ve been in and out of this church to concerts. We descend the steps and onto the sidewalk at the upslope end where the riser is the proper height and it’s easier to step onto the sloping sidewalk.
2. New stairs down to a steeply sloping driveway from the front entrance to a house. It’s scary what the homeowners will need to manage; I can’t imagine what it will be like in the winter time. I understand that the owner plans to rent space to students. A mini-commercial property? (It was seeing these stairs that prompted me to post this blog)
3. A stair riser that changes in height from one end to the other in order to rest on the sloping ground. These stairs are to a landing at the main entrance of a recreation centre. I was told there was an accident there and a person injured. Surprise. Surprise.
4. A sloping washroom door threshold in a hospital. The slope is very slight but it’s there, 1.0 inch in 5.5 inches, 18.1%. I knew it was there but days after noticing and measuring it I still stumbled a little going into the washroom! (Ref. 1)
5. A floor that slopes down from the door of an elevator on a palliative care floor in a senior’s retirement residence. It’s slight but it’s there and noticeable, at least to me.
6. A floor in the patio of a hotel that steps down about 2.0 inches from one area to another. It’s barely noticeable but it’s there, stepping up or stepping down.
7. Big, tank-track-size potholes in roads; not exactly tiny. But also tiny potholes. You can see cars wobbling after they go through some of these potholes. A friend sued the city about one that damaged his car. I called 911 about another left at a construction site.
8. Road-side and parking lot curbs that change height a tiny bit. See my blog posted September 2. 2021, an eye opener if you don’t mind me saying. (Ref. 2)
9. A floor in a private athletic building that changes level in going from one area to another. But, attention is drawn to the change in level with a brightly colored yellow painted threshold. Good. I was impressed by what was done in this building.
10. A surface that changes in height from the sidewalk to the roadway. Attention is also drawn to the change by brightly colored yellow paint. Good I see this a lot in towns and cities as I’m sure you do.
11. Tennis and pickle ball courts in quite level terrain but with a slight cross slope to the courts.
12. A large athletic field constructed on natural soils; Good – except for one corner on deep fill soil; Bad. Foundation and geotechnical engineers learn early to separate the foundations on different soils. Fill soil settles more than natural soil. The pyramid builders in ancient Egypt learned to do this.

I learned long ago if I was walking on a construction site and saw something dangerous like a deep trench in unstable soil and workers in the trench, you draw attention to the risk.

But, what do you do about the “tiny”, accident and injury-prone defects in the built environment noted in the above list? Should I go around knocking on everybody’s door? Does anybody know?

References

1. More tiny causes of slip, trip and fall accidents. Posted March 15, 2023
2. My personal slip, trip and fall accident, #1. Posted September 2, 2021
3. My personal slip, trip and fall accident, #2. Posted February 26, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, June 16, 2023. ejorden@eastlink.ca)   

I was troubled by the article in The Chronicle Herald week ago Friday that noted the engineer’s role in innovation and iconic advances in society but was silent on our role in the built environment, that is everywhere. Then went on to express concern that “…the breadth of expertise and the engineering profession’s impact on the world around is largely unseen.” (Ref. 1)

This in a report in the newspaper on a talk by Gerald McDonald, Chief Executive Officer, Engineers Canada.

I don’t think our role is unseen. It’s staring us in the face in the built environment that would not exist if not for engineers designing, constructing and maintaining it. We just got to see what we’re looking at.

I suggest addressing this concern by taking a cue from Jane Goodall’s focus on kids who will arrest climate change when they grow up – Jane talked about this in Halifax last Saturday. (Ref. 2) Jane is not focusing on politicians and prominent people to fix climate change. In her spirit, we must focus on the humble engineer toiling away in the built environment, getting his hands dirty and mud on his boots providing habitat for the man in the street. Ye shall know him by his iron ring.

(For those of you who forgot, Jane Goodall is an English primatologist who studied the social and family interactions of wild chimpanzees, starting when she was 26, and changed the way we think about humans. She travels the world today, at 89 years of age, writing, speaking and spreading hope through action to make the world a better place)

There’s no question that advances like the following are important – shepherded by engineers:

• Helicopter safety
• Harnessing renewable energy
• Launch of the first Atlantic Canadian-built satellite into space
• The Canadarm
• The pace maker
• Halifax Central Library
• Confederation Bridge

Shepard’s focus on the engineer’s role in the big stuff is good – engineers are even in space as I write – but, so too is the engineer’s role in the design, construction and maintenance of the built environment that is comprised of the following, and more:

• Buildings – residential and commercial. There are more hi-rise and low rise buildings in the world than any other structure. Think about that.
• Water treatment and supply systems to and from the buildings
• Sewage collection and treatment systems
• Storm collection and drainage systems
• Foundation support systems like spread footings and piles
• Foundation subsoils
• Parking lots and airport runways
• Towers, like hydroelectric towers
• Chimneys, particularly the tall ones
• Highways and roads between the buildings and beyond
• Highway embankments, cuts and fill slopes
• Hydraulic structures like canals (eg. Shubie canal)
• Electric power supply systems
• Bridges – small like over highways, large like suspension bridges over water, very large like the Confederation Bridge
• Hydroelectric dams like Mactaquac in New Brunswich
• Marine structures like docks and wharves, breakwaters, and coastal protection
• Ships – designed, constructed and maintained by engineers
• Planes – same role as for ships
• Etc.

These structures come into being and are maintained by engineers working in the civil, foundation, geotechnical, environmental, mechanical and electrical fields. What we have in common in our different disciplines is a creative desire for problem solving.

I felt good as that loooong list above came into being. We engineers are everywhere producing and maintaining the built environment and helping alter the natural environment, carefully. Gerald McDonald knows this and could easily inspire a complementary piece in the The Chronicle Herald.

References

1. McDonald, Gerald, Tap Engineers For New Ideas, The Chronicle Herald, Friday, May 19, 2023
2. Jane Goodall’s talk in Halifax, May 27, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, May 31, 2023. ejorden@eastlink.ca)   

It’s a good question because, for all the importance attached in law to the standard-of-care and reasonable-person concepts, there are few concrete examples to guide the design engineer. Concepts are nice – something conceived in the mind – but you got to get out of your head and get concrete – something characterized by actual things or events. (Ref. 1)

There are few concrete examples of the standard of care in Dr. Google or Wikipedia, nor in the engineering books, to guide the design engineer. (Ref. 2) There’s very little on when he should design above the minimum standard set by the National Building Code (NBC). (Ref. 3) Go read and see for yourself.

That’s what I learned during my research, prompted by realizing most engineers don’t even know about the standard of care. Then I wondered, how many look at the minimum requirements of the NBC and sometimes figure they’ve got to design to a higher standard? Then, I thought, how many civil litigation lawyers and claim adjusters know about these issues facing design engineers? Then I got scared and figured I’ve got to write about this – get it out in the open.

***

Before we go a bit further – just a bit, because I want to alert you to these issues not educate you – this is how these concepts are described in law dictionaries and Dr. Google:

The standard of care means “…the degree of care that a reasonable person should exercise” as put by Black’s Law Dictionary, 4th edition 2011. (Ref. 4)

Put another way in more detail, the level at which an ordinary, prudent professional with the same training and experience, in good standing, in a same or similar community would practice under the same or similar circumstances. (Ref. 5)

Or “… what is reasonable in the circumstances” according to Dr. Google. (Ref. 2)

A reasonable person according to Black is “… a person who exercises the degree of attention, knowledge, intelligence, and judgement that society requires of it’s members for the protection of their own and other’s interests. The reasonable person acts sensibly, does things without serious delay, and takes proper but not excessive precautions”.

Or, as put by Dr. Google “A person who is thought to be careful and considerate in their actions … the way a typical person with “ordinary prudence” would act”.

***

I’ve got queries out to two engineering friends, one who worked as a design engineer for many years and another who worked in construction. I asked each how often they came across situations where something more than the minimum NBC standard was in order. I’ll let you know when I hear back.

Like, for example, if designing to a factor of safety of three (3) is normal – the minimum? – are there times when it should be greater, perhaps (4)? Should a steel or concrete beam be deeper than normal, a column larger, a concrete slab thicker, a storm drainage pipe bigger?

Here’s a question: To what extent is a designer liable if he designs for the Code’s minimum standard – and goes happily on his way – when something higher is order? What’s the big deal, he met the NBC’s standards?

(A factor of safety of three (3) means something is designed three times stronger or bigger than it needs to be before it breaks or falls down)

I asked three other friends – two engineers and an oceanographer who investigated the cause of failures and accidents for years – about the standard of care and the reasonable person. They didn’t know about these concepts.

***

So, what’s a reasonable person in law or insurance to do about a situation like this? Hmmm? How about first asking your expert if they’re aware of these concepts. Then, depending on their answer ask how well their work would stand up to a peer review. If they’re important concepts in Law and Dr. Google, it seems they would be important concepts in the forensic investigation of a failure or accident.

And as you’re asking these questions, remember, there are no concrete examples in the engineering text books to guide the reasonable engineer on when to design to a higher standard than the NBC minimum.

(I may be out in left field a bit with some of these comments but if they stimulate thought about these concepts in the concrete world of engineering design, construction and forensic investigation then I’ve achieved something)

References

1. Merriam-Webster dictionary
2. Dr. Google May, 2023
3. National Building Code (NBC), most recent edition
4. Blacks law dictionary
5. A Bundle of Blogs: On assessing the standard of care. Posted August 12, 2022

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, May 19, 2023. ejorden@eastlink.ca)   

Climate change will increase the number of disputes and insurance claims. These will occur, for example, because designing for strong wind on a building or tower, heavy rain on a storm water system or big waves on a sea wall all depend to some extent on past knowledge. This knowledge will be more limited for bigger or lighter winds, rains and seas as we learn about the effects of climate change.

The design engineer – a reasonable person – will take an educated guess on the effect of the weather on his structure but it will be a rougher guess as we climb up the learning curve.

(I mean a reasonable person as referenced in the concept of the standard of care. (Refs 1, 2) Design engineers will make reasonable decisions during climate change)

My thoughts on this arose on learning about a failure caused by a “mother-of-a-rain-storm” – in the opinion of some.  The erosion and sedimentation control structures on a construction site failed and a lake was contaminated by sediment.

When we design a structure today where climate is a factor, we must now factor in climate change, and the uncertainty associated with this process as we learn. 

For example, in the past we might have designed a structure for a 1 in 50 year rain storm.  Today we must design the structure for a more or less severe rain storm depending on the expected climate change in the area of the structure. But, how much more or less?

Also, in the past we had codes and handbooks to guide us on design of structures for a particular storm.  Today I expect that type of guidance has not kept up with climate change and the decision of a reasonable person will prevail in design. 

Do you want more on the answer to the question in the heading?

In the years ahead, climate change will result in over-design – more costly structures, and under-design – more failures, disputes and claims. The reasonable person, the design engineer, will know the risk and attempt to reduce it. To give you some idea of what they’re up against, consider the rough estimate of a two (2) metre rise in sea level off our shores over the next 50 years, according to one friend, (Ref. 3) and a few feet to a few metres according to another. (Ref. 4)

References

1. Dr. Google and Wikipedia will give you an idea about the standard of care and the reasonable person – an okay start to understanding this concept
2. A Bundle of Blogs: On assessing the standard of care. Posted 2022/8/12. There’s a lot of good reading in these blogs, particularly Blog #5 in the Bundle, and reference to sources. Scroll down the right side of www.ericjorden.com/blog to the year and month, 2022/8/12.
3. Comment by a friend, an oceanographer, about sea level rise based on what was known about climate change a few years ago. April, 2023
4. Fillmore, Peter, personal communication, April, 2023

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, April 29, 2023. ejorden@eastlink.ca)   

We learn from failures. They contribute to successful design. I also like investigating the cause of failures as a means of resolving disputes, sans judicial process. There’s too much discord in the world now without duking it out in court too.

You can read all about learning from failures in To Engineer is Human, The Role of Failure in Successful Design by Henry Petroski. He cites examples of well known failures like,

• The Tacoma Narrows Bridge in 1940 – a video online of the failure is something else to watch. Lesson: The effect of wind on a suspension bridge like those over Halifax Harbour.
• The Nyatt Regency Hotel walkway collapse in 1981. Lesson: Tiny, inadequate structural connections can cause big problems and the deaths of 114 people.
• Roof collapses: The Hartford Civic Centre roof collapse in 1978 and the Kemper Arena roof collapse in 1979 Lessons: I haven’t researched the causes but easy to imagine – an initial hypothesis – inadequate structural design and/or construction of the roof support system.
• We all know about the Ocean Ranger going down off Newfoundland in 1982. Lesson: Provide backup in the event sea water breaks a window, as happened in this case, and gets into the ballast control room. And this cause the control panel to malfunction and the drilling platform to roll over in the rough seas running at the time.
• The space shuttle Columbia exploding on re-entry in 2003. Lesson: Be wary of cultural traits and organizational practices detrimental to safety being allowed to develop as happened in this case.

Petroski explains what was learned from these failures and others and how engineers think when they’re designing a structure.

Enough has been learned from failures that engineers often know the probable cause of a failure before they get on site. I’ve told you this before.

Petroski’s book is a good read – almost exciting – in fairly simple, jargon-free language. There’s the odd big word and abstract concept but not many. He also mentions a couple of other good books on failures which I mention below. One of these books is considered required reading for engineers, architects, civil litigation lawyers, and insurance claims managers.

Read his book, and like me, you’ll go about your daily chores looking and seeing the failures in our built environment. For example:

• A paved driveway with cracks a couple years after the asphalt truck left. Lesson: The subgrade of a simple driveway needs to be well drained to prevent frost heave. Sometimes to a depth of two or three feet rather than inches, if you don’t want any cracks at all.
• The varying height of a curb along a short stretch of residential road. Lesson: The road bed needs to be well constructed and compacted right out to the curb.
• A leaning basketball practice hoop in a kid’s playground a few days after construction. Lesson: Even a kid’s hoop needs to be founded deep enough in the ground and the back fill soils well compacted.
• The thump-thump at a depression in the highway. Lesson: The subgrade and highway embankment need to be well designed, constructed and compacted everywhere, particularly where pipes are laid beneath the highway in a trench after the highway is constructed.
• The sloping door threshold in an elder’s washroom. Lesson: The floors in an elder’s facility need to be designed and constructed at the same level – a simple design and construct problem.
• The irregular, sloping floor surface in a high rise. (I know something about high rise construction. When I saw this – an easy call – I thought sloppy, too fast construction. I knew the job supervisor and the pressure he was under to get the high rise up) Lesson: Take the time to support the floors properly during construction, ensuring the concrete forms are level and well supported before placing concrete.
• A highway slope failure – a mini landslide – where soil has been excavated to form the highway. For example, the slope on the west side of Highway 102 at Exit 10. Lesson: Excavate the slope at the angle of repose of the soil.
• A lake contaminated with sediment from a construction site. Lesson: Design and construct adequate erosion and sedimentation control structures using simple, well understood methods in handbooks.

(I can’t help but think I could prepare a similar list to the above for slip, trip and fall accidents, for certain the ones that I’ve investigated. Another time)

An experienced engineer knows the probable cause of these failures from the get-go.

Some of you will say some of these failures are due to poor construction. I will say you’re right, in a sense. But, I will point out that the poor construction is due to poor construction inspection – quality control – looking and seeing during construction that you’re getting what you’re paying for – which is a design task.

***

Based on what the engineer in me knows, there are some places I won’t go and things I won’t do because of suspect design and/or construction.

And, increasingly, I’m less inclined to fly. If the airlines can mess up the scheduling like they did last Christmas could they mess up plane maintenance and repair? Look what happened to the space shuttle Columbia mentioned above.

Plane maintenance is sometimes contracted out – and sometimes to the lowest bidder, who must focus on the bottom line as well as fixing the plane.

I thought this on a chat with a friend who is an aviation mechanic, months ago and well before the Christmas scheduling mess.

It’s not just me. I exchanged emails with a friend a few days ago who investigates traffic accidents. He was on his way to Orlando, Florida to take a course in accident reconstruction, and wasn’t looking forward to flying. I wonder why?

***

The lists in this blog have come from an engineer’s love of failure and learning from them. That engineers make mistakes is forgivable; that they catch them is imperative.

I had that concept drilled into me years ago – pre-engineering – by Major James A. H. Church, our instructor when I did a two year diploma course in land surveying at the College of Geographic Sciences in Nova Scotia: It’s okay to make a mistake as long as you catch it! The Major was fierce about this.

References

1. You could be excused for thinking that everything is falling down. Blog posted July 23, 2020 Updated October 13, 2020
2. What’s in the built environment and how many ways can it fail? Blog posted July 8, 2020
3. How many ways can a building fail and possibly result in civil litigation or an insurance claim. Blog posted July 10, 2014
4. Nicastro, David H., ed., Failure Mechanisms in Building Construction, ASCE Press, ASCE, Reston, Virginia 1997 This is a real good, well researched read by the American Society of Civil Engineers.
5. Petroski, Henry, To Engineer is Human, The Role of Failure in Successful Design, Vintage Books, Random House, Inc., 1984 Petroski covers a lot of ground in 17 chapters, 251 pages and pithy comment. As he says in the Preface, the book is his answer to the questions “What is engineering?” and “What do engineers do?”. You’ll read some of the answer in Chapter 14, page 172, Forensic Engineering and Engineering Fiction. And the rest of the answer in the remainder of the book.

Appendix: Causes of Failure

Petroski also notes causes of failure as cited in Thomas McKaig’s 1962 book Building Failures. This is a widely known collection of case studies intended for the use of engineers, architects, contractors, and claims managers. The following list in McKaig’s book comes from another, long ago source lost in the mists of time, but still rings with relevance:

1. Ignorance a. Incompetent men in charge of design, construction, or inspection. b. Supervision and maintenance by men without necessary intelligence. c. Assumption of vital responsibility by men without necessary intelligence. d. Competition without supervision. e. Lack of precedent. f. Lack of sufficient preliminary information.
2. Economy a. In first cost. b. In maintenance.
3. Lapses, or carelessness a. An engineer or architect, otherwise careful and competent, shows negligence in some certain part of the work. b. A contractor or superintendent takes a chance, knowing he is taking it. c. Lack of proper coordination in production of plans.
4. Unusual occurrences a. Earthquakes, b. Extreme storms, c. Fires, d. And the like.

Petroski’s book also notes some causes of structural failure as listed in D. I. Blockley’s book, The Nature of Structural Design and Safety, another good read:

1. Limit states a. Overload: Geophysical, dead, wind, earthquake, etc.; manmade, imposed, etc. b. Under strength: Structure, materials instability c. Movement: Foundation settlement, creep, shrinkage, etc. d. Deterioration: Cracking, fatigue, corrosion, erosion, etc.
2. Random hazards a. Fire b. Floods c. Explosions: Accidental, sabotage d. Earthquake e. Vehicle impact
3. Human-based errors a. Design error: Mistake, misunderstanding of structural behaviour b. Construction error: Mistake, bad practice, poor communications

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, April 20, 2023. ejorden@eastlink.ca)   

Archaeology is a very interesting field of study considering it’s everywhere beneath our feet. In that regard, it’s very similar to geotechnology, my first love in engineering. Investigating the cause of failures and accidents in the built environment are my loves now.

Archaeology v. Geotechnology

Geotechnology studies the different layers of soil at a site and their physical properties. This is done for supporting structures in the built environment. (Ref. 1) Archaeology studies objects found in layers of soil to learn how people lived in the past and engaged with the environment. Objects like tools, pottery, jewelry, stone walls and monuments.

Similar exacting investigative procedures are used in both fields of study – the identification of different layers of soil and the identification of objects in the layers. I was struck by the similarity on reading up on archaeology.

A difference is that archaeologists want to see objects in the soil and geotechnologists don’t – geotechs don’t want anything messing up the engineering properties of the soil.

Archaeological specialties

There are different specialties in archaeology like industrial archaeology, coastal and marine archaeology, building archaeology and battlefield archaeology.

Marine archaeology was practiced by Eric Allaby, author of The Sea Wins, a report on more than 40 ship wrecks in the Bay of Fundy. He dove on the wrecks of many of these ships. I imagine similar was done in study of some of the approximately 250 ship wrecks on Sable Island.

There are no extraterrestrial archaeologists yet, though NASA does employ an archaeologist to study satellite images.

Historians also study the past, but they do so by using the written and oral records. Archaeologist can delve deeper into the past to study the thousands of years of human endeavour that occurred before written or oral records began.

Treasure hunting and archaeology

The treasure hunting on Oak Island near Chester on the South Shore of Nova Scotia can easily be seen as a form of archaeology in practice.

Forensic archaeology

Forensic archaeology is an emerging science where archaeologists collect evidence for recent criminal investigations – especially in cases involving murder, genocide and war crimes. It’s also relied on for victim identification following disasters such as earthquakes, flooding, terrorist attacks, fires or plane accidents. We’ve had our share of those in recent times.

The science is well described in a Practical Encyclopedia of Archaeology. (Ref. 2) (I must say I liked seeing the word Practical in the title.) Forensic Science, the Basics is also a good read. (Ref. 3)

Forensic archaeology is also used to solve ancient puzzles, such as the identity of Jack the Ripper – a woman who was hung for another murder about that time, and only identified as Jack the Ripper years later. Or identify the cause of Beethoven’s death – lead in the medicines he was prescribed. (Ref. 2)

Forensic archaeology is being relied on today in the investigation of reported war crimes in Ukraine.

Like geotechnical engineers, what forensic archaeologists bring to the forensic process is a detailed knowledge of how to excavate the ground for buried remains, what to look for and how to analyse the data found. Both fields of study start with simple walk over surveys and aerial and drone photography.

Archaeologist have taught the police how to proceed from these simple tasks and be systematic and precise when excavating the ground beneath their feet – read, the emerging field of forensic archaeology.

References

1. What is geotechnical engineering? Posted December 21, 2021
2. Catling, Christopher and Bahn, Paul, The Complete Practical Encyclopedia of Archaeology, 512 pp, Hermes House, England, 2013. See the chapter on Forensic Archaeology page 226
3. Siegel, Jay A. and Mirakovits, Forensic Science, the Basics, 505 pp, CRC Press, 2nd edition 2010

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada, March 26, 2023. ejorden@eastlink.ca)