Civil procedure Rule 55 will improve expert’s reports and forensic engineering investigation

Expert’s reports can be written better and there are resources available to enable them to do this.  This need will be driven in part by civil procedure rules such as Rule 55 in Nova Scotia, Canada.  These rules require an objective presentation of opinion to the court and a statement of the certainty with which these opinions are held.

Rule 55 will promote better report writing and forensic engineering investigation

When I first prepared a report two years ago according to the requirements of Rule 55 I was struck by the potential for this rule to promote better expert report writing,  And, by extension, better, more thorough forensic engineering investigation.  You can’t write a good report unless you’ve carried out a good investigation.  The rule reduces reliance on discovery in the civil litigation process and increases reliance on experts’ reports, and, by inference, sets a high standard for the reports.

Reason for poorly written expert reports – but no excuses 

I have been troubled by the poor composition, unsupported statements, and leaps of faith in drawing conclusions – some that would scare a tightrope walker, that I’ve seen in some experts’ reports.  No surprise given that we engineers and scientists like to measure things, crunch numbers and analyse data.  We are not wordsmiths by nature.  But this doesn’t relieve us of the responsibility to communicate our findings in simple English and to do it effectively.

Not to fault the techncal expert too much.  We are not educated and trained to communicate with lay people.  We then practice for several decades communicating for the most part with other technical types – no simple English skills needed; jargon only spoken here.  Finally, we are retained in later years for our extensive technical knowledge and experience and presented as experts to the courts – only to find we can’t write and speak simple English to civil litigation lawyers, judges, and juries.

Nor is the civil litigation lawyer – the wordsmith in the process, relieved of a responsibility to confirm that the expert they retain can present their findings in well written, laymen’s terms.  That they can write so judges and juries can understand.  The role of the expert in the judicial system is to interpret and explain technical material.  One role of the lawyer is ensuring that he or she understands the report before it goes forward.  The lawyer is like a gate keeper.

Being technical is neither an excuse nor the justification for poor writing.  The inability to write well is a career-limiting short-coming (see Ref. 1) – and a potential embarrassment to lawyers, judges, and juries, not to mention the engineer and the scientist.

Source of experience leading to my views on the state of expert report writing

My experience leading to these views has been with engineering and legal firms ranging in size from sole practicioners to 50 to 75 staff.  Firms located in eastern and western Canada, and overseas in Australia, the U.K., and the Caribbean.

However, my colleague, Gary Bartlett, noted that he experienced a culture in much larger organizations – 200 staff, that encouraged and required good writing skills, and they achieved this (1).  Gary was an electrical engineer with the Canadian air force – air crew, for about 12 years then with the aerospace industry for at least another 25 years.  He still writes reports for the industry.

So, while there is a problem out there, the character and extent of it varies.  It behooves the lawyer in selecting an expert to learn a little something about where his expert is coming from.  I plan to publish an item in future on how to find an expert and what to look for.

Sources for expert report writers

CDs and books

I was prompted to write this item on receiving the latest edition of a newsletter from Expert Communications, Dallas, Texas, a few days ago.  This firm provides expert witness training tools and other services for experts.

The newsletter announced the availability of a CD on report writing entitled, Expert Report Writing: Effective and Defensible.  The CD is an hour-long teleseminar of a discussion between Rosalie Hamiliton of Expert Communications and Steven Babitsky, president of SEAK, Inc.  SEAK also provides services to experts.

Steven is formerly a trial attorney and a co-author of Writing and Defending Your Expert Report.  This book is one of the best I’ve read and studied on the subject.  Every expert should be given a copy by their retaining counsel.

Rosalie told me last Thursday that If you have Steven’s book you don’t need the CD, although they do complement one another to some extent.  But, she says – and I agree, that if you don’t have time to read a book – and many of us don’t these days – and actually like to get your education via oral and video presentations, then the CD will provide some insight into this important topic of report writing – and possibly contain a zinger from Steven Babitsky.

Critical thinking course

Talking about oral presentations, one of the most valuable experiences I’ve had in recent years, with respect to my practice in forensic engineerng investigation and the accompanying report writing, was to take a course in critical thinking.

This was an intensive, year-long, two, 1.5 hour lectures a week, course given by Professor Chris MacDonald at Saint Mary’s University in Halifax (Chris is now at Ryerson University in Toronto).  There was considerable emphasis in the course on looking critically at the basis of statements made to us and that we make; What’s the statement founded on?  What are you personally saying and basing your statement on?  These are critical questions for an expert to keep in mind when writing a report.

(You might be interested in Professor MacDonald’s blog on business ethics and behaviour at www.businessethicsblog.com  He’s had it up for over six years – and it’s well written.  It’s been rated one of the most influencial business blogs a number of times since he put it up)

The importance of instruction in critical thinking can be gathered from the fact that hundreds of first year students at Saint Mary’s and other universities are required or encouraged to take this course.  The course was given by three different professors the year I took it.  My class had about 200 students.

Experts, regardless of how experienced, well known, and long in the tooth they might be would benefit from a course like this – and their expert reports would be better for it.

But, like reading books, not everyone can take time out to take courses at a university.  I’m beginning to think that sources like those at www.thegreatcourses.com can help solve that problem.

This firm offers several hundred courses on DVD on a range of topics including critical thinking, reasoning, and writing.  The presentations are good and reasonably priced.  You receive a synopsis of the course with the DVD if you still want to do some reading.  A transcript of the lectures can also be purchased.  Some of the courses are interactive.  I have three of their courses on reasoning and writing.

Arguing and report writing

Gaining some understanding of Toulmin logic would also benefit those of us writing expert reports.  I see it as a practical logic as opposed to a formal logic.  Toulmin advocates – analogous with existing practice in law – a procedural rather than a formal notion of validity.  He outlines a way that assertions and opinions can be rationally justified.

His text, The Uses of Argument, is a hard read because of the terminology and style of writing in vogue in the U.K. in the 1950s when he first published his ideas.  But, fortunately, you can go on-line and view graphical representations of his ideas which I thought were quite good.  There are also courses and lectures on his methods in simple English.  The illustrations will remind experts in writing their reports of the importance of ensuring their statements are well founded.

There’s no shortage of sources on writing better expert reports

There’s no shortage of guidance and no excuse for not writing better expert reports.  This will come about driven by the high standards required by civil procedure rules like Rule 55 in Nova Scotia.  Rules like this will out the poor writers.

References

  1. Personal communication. Gary Bartlett, P.Eng., VP Engineering, (ret’d), IMP Aerospace, Halifax, Nova Scotia, Canada
  2. Expert Communications, Dallas, Texas www.expertcommunications.com
  3. SEAK, Inc., United States www.seak.com
  4. Toulmin, Stephen E., The uses of argument, updated edition, 2003, Cambridge

In the beginning there was civil engineering

In the beginning there was civil engineering.  Well, possibly shortly after military engineering.  And from civil engineering came forth other engineering disciplines.  And society saw that this was good.

Including, good for civil litigation lawyers and insurance claims managers – good in the wide selection of engineering expertise available to a forensic engineer investigating the cause of a client’s problem.

I’ve written this item to introduce you to some of the different engineering specialties.  These are listed below.  Lists can be boring so I’ve added a little history and my take on how some specialities got started.

Society has been “engineered” for 1,000s of years

Engineering has contributed to the development of society since the beginning of human existence.  Back when humans started to give up a nomadic way of life, settling down, and erecting more permanent shelters – structures, as in built-environment.  Civil engineering would have developed as the built environment developed.

I’m certain that military engineering evolved at the same time considering how difficult societies can be with one another.

Some literature indicates that the earliest practice of civil engineering may have begun between 4,000 and 2,000 BC in ancient Egypt and ancient Mesopotamia (ancient Iraq). Construction of the pyramids in Egypt (circa 2,700 – 2,500) might be considered the first instances of the construction of large structures.

Also, the manner in which the blocks in the pyramids were fitted together demonstrated an early appreciation of a very basic and important principle in geotechnical and foundation engineering. The beginning of geotechnical engineering?

The Romans developed civil structures throughout their empire (circa 2,700 BC – 410 AD) including aqueducts, insulae (a kind of urban apartment building), harbours, bridges, dams, and roads.

(I must confess, I don’t know what was happening in Asia and other parts of the world. For certain, the built environmennt and civil engineering were developing in areas other than in Europe)

The “first” civil engineer

The term, “civil engineering”, was coined in the 18th century to incorporate all things civil as opposed to military engineering.

The first self-proclaimed civil engineer was John Smeaton who constructed the Eddystone Lighthouse in Great Britain.  In 1771 he and some of his colleagues formed the Smeatonian Society of Civil Engineers.  In 1818 the Institution of Civil Engineers was formed in Great Britain essentially formally recognizing civil engineering as a profession (but, I’ve seen some information about the formation of a professional body in France somewhat earlier).

Evidence of the modern practice of civil engineering

Modern practice in civil engineering and its specialties can be seen today in the development of Dartmouth Crossing outside Halifax, Nova Scotia, Canada.

A natural environment has been turned into a built environment almost overnight. A built environment that includes:

  • Engineered single and multistory retail, residential (hotel), and service buildings,
  • Roads,
  • Small dams,
  • Small bridges,
  • Structural fills of soil and rock,
  • Deep rock cuts,
  • Storm water and domestic sewage collection and treatment systems,
  • Water supply and distribution systems, and,
  • Electrical power distribution systems.

Civil engineering takes place today on all levels of society. In the private sector, from individual home owners to international companies. In the public sector, from municipal governments to national governments.

Where did the different engineering disciplines come from?

Today there is a long list of specialized areas in civil engineering to serve and provide for the built environment.  They can all be called on in forensic engineering investigation to determine the cause of a failure in the built environment.

Where did these specialized engineering fields come from?  They developed as the needs of society developed.

Computer engineering, an easy example to understand, developed and came to be recognized as a field of study as computers developed in the last 50 to 60 years.

Another, fairly easy example, is structural engineering – for certain, developed if not named 1,000s of years ago, because structures had to be held up somehow.  Structural engineering provides for the support of structures.  There are no sky hooks.

There was technology before today’s technology-saturated age. Think industrial revolution, a time when technological development would have been as intense for the time as technological development is today.

It’s easy to understand mechanical engineering and electrical engineering splitting off from civil engineering during the industrial revolution and named as such.  Chemical engineering might not have been too far behind applying the principles of chemistry as this science developed.

Geotechnical engineering grew out of the science of soil mechanics, developed during the 1930s.  It was recognized then that everything in the built environment is supported on the ground, and that soil, rock and groundwater are construction materials that must be engineered properly.

Take a look at the following list of engineering specialties available to society and the forensic engineer to gain some appreciation of where we are today:

Some areas of civil engineering

  1. Structural engineering
  2. Foundation
  3. Geotechnical
  4. Construction
  5. Forensic
  6. Materials
  7. Mechanical
  8. Electrical
  9. Industrial
  10. Chemical
  11. Municipal
  12. Transportation
  13. Surveying
  14. Environmental
  15. Hydraulic
  16. Aeronautical
  17. Computer

References

  1. Encyclopedia Britannica
  2. Pears Cyclopaedia, 107 ed., 1998
  3. Blake, L. S., ed, Civil engineer’s reference book, 3rd ed, Buttherworks, 1975
  4. Chen, W. F., ed, The civil engineering handbook, CRC Press, 1995
  5. Wikipedia

 

 

 

 

Flying objects, injured people, and forensic engineering investigation

I read the report in yesterday’s Chronicle Herald about flying pieces of metal injuring four people on a popular ride in Yarmouth.

It occurs to me at this distance that this should be a fairly easy failure to investigate with a visual assessment by perhaps an experienced mechanical engineer.  For certain, to at least enable a tentative statement of cause.

This is because the surfaces from which the metal came loose are likely to be exposed to view.  And because there are likely to be other units (chairs?) in the ride apparatus that are identical with the metal still in place.  This would afford a before and after comparision of the in-place condition of the pieces of metal.  This type of comparision can yield good evidence.

(A failure in engineering occurs when something in the built environment doesn’t perform properly)

A visual assessment doesn’t sound very technical but it is always valuable and sometimes all that is necessary.  And it is an essential part of the main steps in the failure investigation process:

  • Acquisition of data
  • Analysis of data
  • Formulation of opinion

One time, I investigated the reason a piece of ice fell from a structure and struck and injured a person.  My investigation was based almost entirely on a visual assessment of the exposed surfaces of the structure.  I did this to some extent from a distance with binoculars and a camera with telescopic lens.

I also was able to compare the condition of the part of the structure involved with other unaffected parts of the structure and other structures in the area that were the same.

I analysed the data – largely taken from a visual assessment, formed my opinion, submitted my report, and, I understand, a dispute that had been ongoing for several years was resolved within a few months.

This situation with the falling ice seems very similar to the situation in Yarmouth with the flying pieces of metal.

At the very least, an initial hypothesis could be formed as to the cause of the problem based on a simple visual assessment.  This hypothesis could then be investigated by more detailed forensic engineering investigation, if this in fact is necessary.

The Nova Scotia Department of Labour are investigating and I’m certain we’ll know the answer soon enough.

References

American Society of Civil Engineers, Guidelines for Failure Investigation, 1989

The Chronice Herald, Thursday, August 2, 2012, page A6

 

Drought can cause property damage

In addition to the potentially low crop yield being reported in the local and national Canadian and U.S. press.

Reports from the Annapolis Valley in Nova Scotia, a prime agricultural area, note  the worst drought conditions in 10 years.  I spoke with one grower several weeks ago who incredulously noted that rain had not fallen on his crops in two months.  This in an area – eastern Canada, where a low pressure system goes through about every three or four days, often accompanied by rain.  We are fond of saying down here that the weather builds character.  I can just imagine what my grower is saying now, possibly unprintable.

Forensic engineers consider the effects of drought in some investigations.

Effects of drought

Foundations of buildings and civil engineering structures can settle or subside in drought conditions.  This can happen to both new and old structures.  This kind of settlement is in addition to that usually predicted by geotechnical engineers during foundation design.  That is, settlement due to the more normal loads on a structure – see the item published July 10, 2012 for comment describing more normal design loads.

(Geotechnical engineers investigate the physical properties of soils and rocks and advise design engineers of the effects of these properties on structures)

Foundation settlement due to drought is not usually considered in engineering design when assessing the loads on a structure in eastern Canada.  This is because this type of settlement is often slight.  Also because there is seldom a scarcity of rain in eastern Canada so we seldom experience drought conditions.

But, it should be considered elsewhere in Canada and the U.S.  And in the future down east considering the possible effects of global warming on climate change as suggested by some. And maybe during the present drought.

(Engineers think of loads as something than can affect a structure and most be provided for or accommodated in design.  There is certainly an argument for considering the effects of drought as a load on a structure even if dismissed quickly most of the timel)

Is this too esoteric a matter for engineers to be concerned with – the effects of drought on conventional structures in the built environment?  I don’t think so.

Let’s not be too quick to dismiss slight foundation settlement due to drought as insignificant.  It can be very significant to transformer foundations in substations and to the foundations of free standing, un-guyed towers and to wind turbines. (Substations are components of an electrical power distribution system)

These types of structures are quite sensitive to foundation settlement.  They are sensitive to a few millimetres settlement, like, less than 5 millimetres.  Whereas more conventional structures – such as many low-rise buildings, can tolerate in the order of 25 millimetres, and some structures somewhat more than this.

How drought causes foundation problems and damage

How can drought cause foundation settlement?  It’s quite easy and the reason will take you back to your high school physics class.

A drought causes the watertable to drop.  We all know about that – think dug wells going dry.  When the watertable drops the groundwater “drains” out of the soil above.  The soil is no longer submerged below the watertable.  The recently drained, relatively dry soil above the watertable – due to the drought, is now heavier.  Think back to your high school physics and the fact that the dry unit weight of a soil is heavier than the submerged unit weight.

Relatively dry soil will settle due to its (increased) weight, due to its increased “self weight”.  Foundations on soil that is settling or subsiding will also settle – go down with the subsiding soil.  And this can be caused by drought as we saw above.

For example, the gardeners amongst us have seen the soil in a recently planted container settle over a period of days.  This is due to the self weight of the soil causing compression or settlement within the soil.  The increased self weight of a soil that is suddenly above the watertable due to a drought will have the same effect – cause the soil to compress.

Another example is the depression across the road at the former location of a construction trench that has been filled in with soil.  A lot of this depression is due to compression within the soil due to its self weight.

The same engineering principle underlies these examples as does the effects of drought.

I can easily imagine drought causing significant settlement that is greater than slight settlement, particularly with recently designed and constructed structures in areas that have not experienced drought before.

The evidence for this lies in Mexico City.  The city has been settling for years, totalling several feet in some areas and causing much damage as you can imagine.  This settlement is due to a lowering of the watertable.  The watertable was lowered when water was pumped from wells in the city over many years.

Pumping is a different kind of assault on the watertable than drought.  But the soil doesn’t care what causes the watertable to drop and its self weight to increase.  When this occurs the soil is going to settle causing greater or lesser damage to any foundations above.

The drought occurring now can conceiveably cause foundation problems.  But a forensic engineer investigating a specific problem would need to look at factors like the sensitivity of the foundation to settlement, the magnitude of the drop in the watertable, the soil, and historical records of drought in an area.

An experienced geotechnical engineer in many parts of North America will consider the effects of drought on a structure.  They might see it as a load on a structure the effects of which – increased foundation settlement, must be provided for by a design engineer.

An experienced forensic engineer will consider the effects of drought when investigating the cause of the poor performance or complete collapse/failure of a structure.

 

 

The role of a professional engineer assisting counsel prepare a Notice of Claim

If counsel decides to take a case after meeting with the client and assessing the merits of his or her claim – see post, June 26, 2012, and the dispute has not been resolved by some other means, then civil litigation formally begins with counsel preparing a Notice of Claim.

Preparing and filing a Notice of Claim is one of the first four steps in the civil litigation process collectively known as the Pleadings – several additional steps continue the process to trial:

  • Notice of Claim
  • Statement of Claim
  • Statement of Defense
  • Affidavit of Documents

The Pleadings concisely define the issues between the parties and set out the facts.  The Notice of Claim describes the parties and the fact that the Plaintiff is starting a legal action in court against a defendant or a group of defendants.  The Statements of Claim and Defence, and Counter Claims are a listing of the facts, including the technical facts.

Counsel, in preparing a Notice of Claim, might take a closer look at the existing information relied on initially in deciding whether or not to take the case.

Deciding to prepare a Notice of Claim and go forward with an action is a critical step for counsel and the client.  It’s a critical step because the Plaintiff has gone public in a sense and is on record that they believe they are entitled to damages for a perceived wrong.  To some extent there’s no turning back.  The decision to prepare and file a Notice of Claim must be well informed – see below, Case #1; Damaged Aircraft Wing.

Professional engineers can assist at this stage by also studying the existing information more closely, identifying the known technical issues and facts, and assessing the technical position of the parties that might be involved in the action.  Some new information is likely to be gathered by the engineer (see list below) because of the critical nature of this step.

(Up to this point – preparing a Notice of Claim – an assessment of merit is based mainly on existing information.  Preparing a Statement of Claim to which the Notice of Claim is typically attached is certain to involve some detailed gathering of new information – see future posting).

The role of a professional engineer would involve carrying out the following tasks.  Technical data from these tasks would contribute to counsel’s assessment of the strength of a case and whether or not to actually prepare and file a Notice of Claim and begin a lawsuit:

  1. Visit the site and visually examine exposed surfaces
  2. Confirm Plaintiff’s complaint that the structure has failed or is not performing properly
  3. Study documents and existing information in more detail
  4. Develop initial hypothesis of failure
  5. Refine identification of technical issues
  6. Assess the technical strengths and weaknesses of the case for each party identified by counsel
  7. Brief counsel on where engineering investigations appear to be leading with respect to an opinion on the Plaintiff’s claim and its legitimacy
  8. Outline main engineering investigative tasks
  9. Revise possible investigative costs based on the main tasks, the engineer’s past experience, and engineering precedents

Case #1; Damaged Aircraft Wing: Assessing technical strength.  A lawyer considered that his client had a claim for more than one million dollars in damages to an aircraft wing.  The lawyer was quite certain about this.  It was understood that hydrochloric acid had formed in an exhaust pipe from a paint shop and dripped on the wing corroding the skin and the spar inside.  A professional engineer was retained to investigate the situation.  He established during a visual examination of the site that the aircraft wing was damaged by acid but the situation was such that the client did not have a strong case.  Preparation of the Notice of Claim was stopped.    

References

  1. Stockwood, Q.C., David, Civil Litigation, A Practical Handbook, 5th edition, Thompson Carswell, 2004
  2. Walker, Janet, General Ed., The Civil Litigation Process: Cases and Materials, 6th edition, Emond Montgomery Publications, 2005
  3. The Civil Litigation Process – An Overview, Heydary Samuel, Ontario
  4. Going to Court: Civil Trial Procedure, Community Legal Information Association of P.E.I., Inc. November 2003
  5. Flow charts summarizing the process of civil litigation under the Rules of Civil Procedure, Ontario, January 1, 2010

 

 

Landslide!

Landslides are frightening and an example of one more way nature has her way with us when conditions are right.  Such a large mass of soil and rock sweeping away everything in its path must be terrifying to see, and terrifying to be in.  I’ve seen the aftermath of large landslides and earthwork failures and investigated some.  They are a humbling experience.

The recent landslides in B.C. at Fairmont Hot Springs Resort and Johnsons Landing on Kootenay Lake certainly fall in that frightening category.  Others in B.C. and elsewhere in Canada, including the Atlantic provinces, are smaller but still serious in causing injury and financial loss.

News reports indicated that geotechnical engineers and geological speciallsts were on the disaster sites within hours of the landslide.  A good thing quickly getting knowledgeable technical people there.  Landslides are engineering failures, particularly when they affect people  The investigations they do and the data they collect are certain to assume the status of forensic engineering investigations.

(Geotechnical engineers are civil engineers who have specialised in the investigation and study of the physical properties of soil and rock as engineering materials)

These large landslides appear to have occurred after smaller landslides along streams – like Fairmont Creek, created dams causing water levels to rise.  Eventually the rising water would overtop the dam and wash it away and downstream.  The mixture of stream water and dam material would pick up other material along the stream bed to create the mass of soil that swept over the inhabited areas as a large landslide.

It’s certain more landslides are occurring in B.C. as I write, both large and small.  If not in or near inhabited areas then in remote areas for sure.

Landslides are natural geological events.  They occur when conditions are right – the strength of the soil on a sliding surface is not great enough to hold back the mass of soil.

The physics principle involved is the same as that underlying the reason we slip on ice in winter and fall and are able to ski on snow and have fun.

Sometimes the strength of the soil is just great enough that the mass of soil stays in place.  Until something comes along to reduce the strength that little bit so it’s no longer adequate.  Or increase the weight of the mass of soil.  That something can be water – rainwater.  The water is said to “trigger” the landslide, a term used by geotechnical engineers and sometimes the general public.

Once the mass of soil starts to move – the land starts to slide, it takes the easiest path like flowing water.  Simply downhill – down a slope, or down a natural channel in the terrain, for example, a water course or stream bed.  The mass of soil in a landslide can be quite “liquid”.

Geotechnical engineers can investigate, analyse, and predict with considerable accuracy that a landslide will occur.  They cannot really say when.  Except perhaps when it’s imminent if they are able to examine the terrain for the signs.  For example, signs like fissures in the ground surface – “tension” cracks to engineers, leaning trees, and muddy water like that seen at Fairmont Hot Springs Resort.

They can also advise with some confidence on the stability of a sliding mass of soil that has come to rest like the geotechnicians did at the Resort.  Their degree of confidence would likely be greater than that possible by structural engineers at the site of a collapsed building like the one at Elliot Lake.

Engineering Investigation

A geotechnical engineering investigation of a landslide – either before the event to predict the likelihood of its occurrence or afterwards to determine the cause – would have the fundamental components of an engineering failure investigation:

  • Gathering data
  • Analysing data
  • Developing an opinion

Data would be gathered in two basic stages:

  • Gather together existing data
  • Gather new data

These basic stages are likely underway at present at the Fairmont Hot Springs Resort and Johnsons Landing.

Existing data is often concerned with conditions at the ground surface and new data with conditions below the surface.

Existing Data

Existing data might consist of:

  • Air photos
  • Infrared photography
  • Topographic maps
  • Geologic maps, particularly soil maps if the sliding mass is in soil
  • Published soil physical properties
  • Hydrogeologic maps
  • Forest cover; vegetation in general
  • Local weather and climate
  • Walk-over surveys (several times during a study of the existing data)
  • Local history and knowledge of past landslides

Reviewing and studying existing data like this, an experienced geotechnical engineer could offer a quite informed and fairly confident statement on the susceptibility of an existing hillside to landslides, or the cause of an existing landslide.

Statements like these have likely already been made about the landslides in British Columbia.

New Data

New data that would increase the confidence of the geotechnical engineer in his opinions would consist of:

  • Surveying (topographic) the site to determine the size and dimensions of the landslide
  • Estimating the volume of soil and rock that slid
  • Augering and drilling boreholes to do field tests and get soil and rock samples for laboratory tests
  • Determining the depth of the sliding surface
  • Constructing groundwater monitoring wells to determine the depth to the watertable and the flow of the groundwater
  • Installing instrumentation to monitor slope movement

Analysis

Investigative tasks like the above provide a lot of data to be analysed.  But the results of the analysis enable well-founded opinions to be formed on the cause of the landslide and remedial work to begin.  The analysis also enables areas prone to landslides to be avoided when building new structures or to be stabilized before building.

Cause of the roof collapse at Elliot Lake

A good initial hypothesis would quickly dismiss inadequate structural engineering design as the cause of the roof collapse.  The structure is likely to be simple in the extreme: Structural concrete slabs supported by regularly spaced columns bearing on concrete footings on good foundation soil.

If design had been inadequate the mall might have collapsed long ago.  The “loads” (see below) in a simple building are easy for structural engineers to calculate and provide for.

Professional engineers are not infallible but we are governed by professional bodies that do watch us closely.  We carry out our designs according to well understood principles and are held to a strict code of ethics.  Cost is a factor in design; designs must be economical, but not at the expense of safety.

It’s sometimes another matter, however, once the construction drawings leave the design office.  Design can be all well and good but construction inspection is sometimes left wanting.

The pressure on design engineers – not much really, is applying fairly simple design principles in providing for support of the structure, for a reasonable fee.  The pressure on builders – quite a lot of pressue, actually, is getting the structure erected as quickly as possible, for the lowest price.  The pressure on the inspector is ensuring the design is implemented properly, sometimes for a reasonable fee and sometimes with experienced, full time inspection, but not always.  Construction inspection sometimes gets the short end of the stick as far as being adequately funded and staffed.

Inadequate inspection and/or faulty construction would be a good second hypothesis as the cause of the failure.

Inadequate maintenance could be a third, particularly if coupled with inadequate construction.  For example, inadequate drainage of corrosive water and exposed, inadequately covered structural steel.

There are many factors that could bring a building down: Corrosion – mentioned above, weather, various aging effects inherent in the choice of materials, original design mistakes – as acknowledged above but unlikely in simple structures, abuse, unexpected loads and external forces.

These items or factors can be divided into two fundamental categories:

  • Static load support deficiences, and
  • Dynamic load deficiences.

Static loads – weight in laymen’s terms, are the basic weight of the building itself and its contents.  A building has to be strong enough to resist gravity and hold itself up.  The static loads can be subdivided into two categories:

  • Dead loads, and
  • Live loads.

Dead loads are loads that never seem to change in a building such as the weight of the floors, walls and roof.  Live loads are loads that can sometimes change in a building due to weather, occupancy, or building use.  For example, the people, furniture and equipment, and possibly vehicles in a parking garage (see below), etc.

Dynamic loads are loads on a building that change during a relatively short period of time.  They are repeatedly applied and released.  Dynamic loads are added to the static loads.  Typical dynamic loads include strong and variable winds, machinery that pounds or shakes the floors of a building (vehicles in a parking garage?), and earthquakes.  Dynamic loads can sometimes cause contruction materials to fail due to fatique.

Any one or more of several factors could have brought the building in Elliot Lake down.  For sure, inadequate design of a simple building is a possibility but, based on my experience, inadequate construction and maintenace are more likely causes, and good second hypotheses.

I propose, but who knows until a thorough forensic engineering investigation is carried out?

Reference

James, Stuart H. and Nordby, Jon J., Editors, Forensic Science; An Introduction to Scientific and Investigative Technicques, 2nd ed., Chap. 23, Taylor & Francis 2005

Unsafe roof debris at Elliot Lake an easy call for a professional engineer

Removing a pile of debris is like the game of pick-up-sticks where you lose if a stick moves.  Only with roof debris your “loss” might be an injury possibly a serious one to yourself or the survivors you’re seeking.

Professional engineers know about supporting and holding things up properly.  That’s what structural engineering is all about.  Having a forensic structural engineer on the first response team would seem to be a good idea.  They are going to be involved in any event determining the cause of the collapse.

Good response leadership – which was lacking at the Elliot Lake roof collapse according to an editorial in Saturday’s Globe and Mail, needs good advice.  What better place to get it than from people who design things to stand up?

Swift action involving engineers is also needed because so much of the evidence associated with a collapse is of a perishable nature – some of it highly perishable.  Steel and concrete fracture surfaces will corrode and weather, debris will be moved and memories will fade.

The first steps in the forensic structural engineering investigation of a collapse are critical and concerned with safety in the debris, the “pile of sticks” that the debris is not at all unlike.  They may also profoundly influence the success of subsequent forensic technical investigations.

The engineer may be requested to assess the safety and stability of a structure for a variety of possible reasons:

  1. To assist in identifying the safest routes through the debris, or identifying areas that must be avoided until stabilized
  2. To assist in identifying components that are in imminent danger of further collapse.
  3. To evaluate methods of stabilizing the structure.
  4. To assist in determining whether it is advisable to provide protection for the public.
  5. To assist in evaluating alternative demolition or dismantling sequences.

An argument could even be made for having the first response team to a collapse site headed up and directed by a professional engineer with a project management background.

References

The Globe and Mail, Saturday, June 30, 2012, page F8 Comment.

Ratay, Robert T., Forensic Structural Engineering Handbook, Chap. 4, The First Steps After a Failure, McGraw Hill, 2000

 

Tasks investigating the cause of a roof collapse

Specialists investigating the cause of a roof collapse like the one in Elliot Lake, Ontario, on June 23, 2012 might do some or all of the following tasks:

  1. Walk around and visually examine the collapsed structure from all angles paying particular attention to the structural elements, their location and condition.
  2. Photograph and film the entire collapsed structure from all angles including from a low flying plane or helicopter.  Include distance, mid range, and close-up sequences.  Also photograph and film the structure during the removal of the debris in the hunt for survivors.
  3. Photograph and film the structural elements where these are exposed to view.  Include close-up sequences.
  4. Interview witnesses of the collapse and occupants of the structure on different occasions prior to the collapse.
  5. Study photographs and videotape taken during the use of the structure.  For example, security camera records.
  6. Study photographs and film/videotape taken during construction of the structure.
  7. Review design of the structure paying particular attention to the structural design.
  8. Review the geotechnical investigation of the foundation soil, rock and groundwater conditions at the site of the structure.
  9. Review the construction drawings and specifications for the structure.
  10. Review the construction, and materials testing and inspection records.
  11. Review the as-built drawings.
  12. Review the structure’s maintenance records.
  13. Identify additional specialists needed to investigate aspects of the structure and the collapse.
  14. Schedule laboratory and field testing of materials used in construction.
  15. Schedule laboratory and field testing of structural elements of the structure.  For example, connections.
  16. Research the literature for similar roof collapses.
  17. Develop a model of the collapse including the progression.
  18. Analyse the data and formulate an opinion on the cause of the collapse.

The role of a professional engineer in counsel’s decision to take a case

Civil litigation tentatively begins when counsel meets with a potential client.  The purpose is to gather information to help him or her assess the merits of the case and decide if he should take it.

A professional engineer could have a role in this meeting, or in consultation shortly afterwards.  This is particularly the case if the legal and technical issues are likely to be complex requiring extensive engineering investigation to support a reliable opinion.

                 “I’ve seen cases that should never have gone forward …”

I’ve seen cases that should never have gone forward.  Not because of a lack of technical merit but because of the client’s limited financial resources to bear the cost of the forensic engineering investigation necessary to determine the cause of the problem.  These would be costs learned about after a claim was filed and discoveries held – and only after a professional engineer was retained to investigate the technical issues.

During the meeting, counsel obtains information from the client’s description of the problem and the damages he believes he has incurred, documents provided by the client, knowledge of witnesses, answers to questions raised by the lawyer, the lawyer’s past experience of similar matters, and comments by an expert on the technical issues.

One of several important considerations covered by the meeting and the lawyer’s review of the facts is the need for an expert on the case.  An expert can make or break a case and if thought to be necessary should be chosen carefully and retained early (Ref.1).  Even if only retained briefly to support counsel’s assessment of merit, in the event counsel decides not to take the case.

If a professional engineer is not included in the meeting, then counsel might confer with one later during his review of the facts prior to making a decision about taking the case.  The engineer would, of course, review the information from the meeting, particularly the documents, and identify the technical issues prior to counseling the lawyer.

The engineer can also provide very preliminary comment on the engineering investigation needed to address the technical issues and to formulate an opinion on the cause giving rise to them.  The engineer would educate counsel by outlining some of the tasks that would need to be carried out during an investigation and the time to do these – factors that can have a significant impact on the cost of litigation.

If the technical issues are complex – and the engineer can certainly help determine that, the monetary claim for damages likely to be substantial, and the lawsuit quite lengthy then this will affect the client’s litigation costs.  The client’s ability to bear these costs is important information in counsel’s decision on taking the case.  An engineer can have a role in assisting counsel make that decision.

Following are tasks that a professional engineer – or any expert for that matter, could carry out during or shortly after counsel’s first meeting with a potential client to assist counsel’s decision about taking the case:

  1. Attend and audit the meeting for technical issues, or meet with counsel shortly afterwards
  2. Review client’s descriptions of the problem and the reasons for claiming damages
  3. Read available documents
  4. Review witness’ statements as soon as taken by counsel
  5. Begin identification of potential technical issues
  6. Begin identification of technical documents counsel to seek
  7. Familiarize counsel on the typical stages and tasks in a forensic engineering investigation, the fact of unexpected follow-up investigations, the fact that investigations can lead in unexpected directions, the time required, and the difficulty estimating costs 
  8. Identify physical evidence, tangible exhibits and possible demonstrative evidence
  9. Brief counsel on parties that might be involved in the potential litigation and their relationship to the technical issues
  10. Provide information that would facilitate early settlement
  11. Note unfavourable evidence for the potential client’s claim
  12. Remind counsel that only one side of the story is known.  The opponent’s story and documents could give rise to a small shift in the technical facts and alter the complexion of the claim
  13. Tentatively assess the technical merits of the case with respect to the potential parties
  14. Outline preliminary engineering investigation and the major tasks involved
  15. Speculate on follow-up investigations
  16. Identify specialists that may be required
  17. Speculate on the order of magnitude of investigative costs
  18. If counsel decides to take the case, and position letters are appropriate, ensure that demand letters, and responses, are based only on well-established technical facts and data as known at the time

References

1. Stockwood, Q.C., David, Civil Litigation, A Practical Handbook, 5th ed, 2004, Thompson Carswell