I was surprised at how my inquiry about a slip and fall accident turned out, and liked what I learned about setting up Zoom and Teams’ meetings.

I came out of the incident determined to prevent similar hiccups in the future with other people and groups I meet virtually. For sure during Zoom and Teams’ meetings about forensic engineering investigation. It was a small hiccup but troublesome. And all this in the run up to the Christmas season, a joyous time of the year.

I was referred to a lawyer and her firm by colleagues who had been approached about investigating the cause of a slip and fall accident. They recognized it was outside their area of expertise and suggested I get in touch with the firm.

I called and we chatted. I learned that the firm may have found an expert. This was fine. I recommended peer review of the expert’s investigation because there are many elements in slip and fall accidents and different approaches to investigating cause.

She suggested a Microsoft Teams meeting to discuss this. We looked at some dates and I suggested one that fit my schedule a couple of days later. She got back to me later in the day to confirm this time was good after conferring with her colleague, a partner in the firm. I noted the time in my journal.

I sat at my desk at the appointed time a couple of days later and waited for an email with the Teams link … and waited and waited. Sometime after the agreed time I went onto other work.

The next day I called and left a voice mail as to whether I had misunderstood the time of our Teams’ meeting. Three days later I sent an email inquiring. The telephone number and email address worked in setting up the Teams meeting, why not now? Hmmm?

(I learned later – see below – that my contact had called when I didn’t link in, and I missed the call)

A good month passed during which I was troubled by what had happened. I also wondered how the young lawyer and her colleague had processed this.

I decided to check the emails again in setting up the Teams meeting. Maybe I checked more thoroughly this time. The penny dropped as I scrolled well down the email page to near my contact’s signature, and somewhat below the text about the meeting time two days hence. I saw a Teams link in the earlier exchange of emails. I remembered seeing at the time what looked like a link but, if I might be allowed some slack, in a quick read no indication it was for a Teams meeting two days later.

It didn’t help that three organizations that I Zoom with weekly and monthly send out a link one or two days early. Then send out a reminder on the meeting day. New meeting technology, new protocols.

This was the first time a misunderstanding like this happened in my years of consulting practice. I wondered, would I still be a bit troubled months from now about the mistake if one side or the other in this matter called me about a peer review? I wouldn’t, seeing as I carried some of the burden, also because I’m too interested in just doing my work – engineers are like that, to a fault.

(A little aside but a little related. I was at an Engineers Nova Scotia Christmas social in Halifax in all that rain last Thursday evening. Much of the talk was the engineering projects we worked on in the past and what we’re doing now that has some engineering in it. Engineers are like that, talking shop all the time. Santa Claus was no where to be seen or heard. This was the case for young and older engineers alike, male and female, and all ethnic groups – we’re a nice mixed bag of engineers Down East)

What about the young lawyer? How did she process this? Fortunately we were in touch early last week and chatted and know a mistake was made. I also learned that they telephoned when I didn’t show up for the Teams’ meeting. I didn’t answer as I tend to shy away when I don’t recognize the number – too much spam out there. I do look at all email – it glares at you from the Inbox.

Think we shared the cause of the mistake but with me carrying the greater burden by not scrolling all the way to the bottom of the e-page and paying closer attention to what was there.

At the end of the day, I’m okay with the effect of this on me – a learning experience.

The take-away? Draw attention to the link on the day the meeting is set up, and follow up with a reminder near the top of the e-page on the day of the Teams or Zoom meeting.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. December 15, 2022 ejorden@eastlink.ca)   

(Abstract: The following is a detailed description of the tasks that an engineer carries out during a forensic investigation. This type of investigation determines the cause of a failure or accident as a means of assisting the resolution of disputes.

(The description is based on my engineering experience in eastern and western Canada, the Yukon, off-shore Nova Scotia and the Beaufort Sea, and overseas. I also relied on 11 well regarded references on forensic and engineering investigation. My description is characterized by a list of tasks as well as 19 sub-lists that help the reader easily understand what’s involved.

(Understanding the tasks is easy, estimating the cost of the tasks can be difficult. An Appendix on costs helps the reader understand this difficulty.

(This blog was originally posted on July 15, 2013. There is little change in forensic investigation in 10 years. What has improved even more is encouraging:

1. Increased reliance on visual and virtual site assessments by an experienced engineer
2. Using drones to take low level aerial video of failure and accident sites both indoors and out
3. Strict guidelines for objective expert reports
4. Interest in peer review
5. Amicable dispute resolution well before the court house steps have been reached

(It’s interesting that a list like the above has proved useful in this Abstract as was found to be the case 10 years ago in the following updated blog)

***

Introduction

How do clients benefit?

Counsel benefits, as well as insurance claim managers, when they have some understanding of forensic engineering investigation.  An investigation determines why – the cause – a structure failed or did not perform properly, or why an accident happened.  Included are environmental accidents, fuel oil spills, and slips, trips and falls. Structures are anything in the built environment.

The process followed by experienced engineers results in a thorough investigation that leads to an objective opinion on cause.  The results can be given in a well written report to standards like civil procedure Rule 55 in Nova Scotia.

What does this blog set out to do?

The following identifies and describes the typical steps, the tasks in a forensic engineering investigation. 

Investigations can be complex and time consuming involving all the steps in the process.  Or simple and quick, particularly when some steps are not needed because of the nature of the failure or accident, or there’s interest in focusing on one key element in the problem. 

The engineer’s experience can also simplify an investigation.  For example, I saw the reason ice was falling from a roof – from across the street with binoculars.  And another time, the reason for a trip and fall accident in a couple of photographs sent me.  Still another, the reason for a fatal motor vehicle accident – even the standard field tests I had to carry out were dangerous.

The process is followed regardless of whether the professional engineer is retained by the plaintiff or the defendant, a claims manager or the property owner, and whether retained as a consulting expert or a testifying expert.

The process is also followed in spite of the fact that the great majority of disputes are settled out of court – many quite amicably after the evidence is in.

The word “forensic” from the Latin forum indicates that the investigative findings assist the justice system resolve a dispute. That’s certainly the case if the thoroughness of a forensic investigation keeps a dispute out of court.

What is a structure and how many ways can it fail?

A structure is anything in the built environment. Look around you – the built environment comprises many 100s of different structures that could go wrong in some way. And 100s of ways an accident can happen.

A structure also includes alterations of the natural environment like highway embankments, earth and rock slopes, land drainage and tunnels driven through soil or rock to carry highways or water. 

A failure can involve total or partial collapse of a structure or inadequate performance of it’s components.

A blog I posted in 2020 is informative as to the number of structures in the built environment and the many ways they can fail. Scary to be truthful. See, What’s in “…the built environment” and how many ways it can fail? Posted July 8, 2020. Look at some of the references too.

Fundamental tasks in all forensic investigations

There are four basic steps in a forensic engineering investigation:

1. Gather data
2. Analyse data
3. Draw conclusions
4. Form opinion

Before and after the failure or accident

At some point during an investigation we are interested in establishing a before-after scenario:

1. What were the conditions existing before the failure or accident?
2. What took place during the incident?
3. What are the conditions existing afterwards – the property damage, the injuries?
4. What caused the incident?

Standard tasks in a forensic engineering investigation

Rigid formulae for investigating failures and accidents do not exist.  But all forensic engineering investigations contain the following steps to a greater or lesser degree.

1. Review documents
2. Visually assess the failure or accident site
3. Video the site from the air with a drone mounted camera
4. Field investigations
5. Laboratory investigations
6. Research
7. Follow-up investigations
8. Analyse data
9. Draw conclusions
10. Form opinion
11. Assess repair and remediation
12. Write report

A visual assessment can be broken down further:

1. Visit and visually assess the site
2. Take low level aerial video with a drone mounted camera
3. Take terrestrial photographs with hand-held and dash cameras
4. Interview witnesses

Field investigations can also be broken down:

1. Describe the failure or accident
2. Survey and document the damage to the structure
3. Determine how the structure was built
4. Determine the site conditions

Research too:

1. Desk studies
2. Leg work
3. Identify building codes and industry guidelines
4. Assess the standard of care

Most of an investigation involves gathering data and most of the report – more than 3/4 – involves analysing and presenting the data.  This points to the importance of the data gathering.  The degree of certainty in the opinion on the cause of the failure or accident is often a function of the amount of data gathered.

In fact, guidelines on failure investigation and forensic engineering issued by national engineering associations (see the References) have strong advice for professional engineers: – “Take only those cases where you can carry out a thorough investigation and gather enough data to be able to give an objective and reliable opinion“.

Following is a brief description of each task in the investigative process:

1. Document Review

Review documents

Reviewing documents provided by the client is an important first step in a forensic engineering investigation.  These documents sometimes provide the only data available to an engineer investigating a failure or accident. Documents include material like the following:

1. Client narrative
2. Discovery transcripts
3. Text material
4. Geotechnical reports
5. Structural design reports
6. Environmental assessment reports
7. Drawings and site plans
8. Construction and site photographs
9. Damage photographs
10. Maintenance records
11. Weather reports – usually rainfall

Additional published documents often researched by a professional engineer include:

1. Legal surveys and descriptions
2. Land development and drainage plans
3. Aerial photography of the area of the site
4. Topographic and contour maps
5. Surficial and bedrock geology maps
6. Agricultural soil maps
7. Hydrological maps and studies
8. Hydrogeological maps and studies
9. Flood plain mapping
10. Mining activity mapping

Documents like these are often studied a number of times during the different stages of an investigation.

Form hypothesis and plan investigation

Information from the documents along with an initial site visit and visual assessment enables the professional engineer to plan the investigation based on what he thinks caused the failure or accident – his initial hypothesis.  Investigations are designed to confirm, revise, or refute the initial hypothesis.

The assumptions made underlying the professional engineer’s initial thoughts on the incident are identified and documented. 

Implicit in the most thorough investigations is an effort to also prove a failure or accident did not occur in some way different from the forensic engineer’s initial hypothesis.

Format of some forensic investigations

Well planned investigations are sometimes set out as follows:

1. Task. Identify and describe each task.
2. Purpose.  State the purpose of each task – what is hoped to be learned.
3. Data.  Describe what is actually learned, the data gathered.

This simple format enables the investigation to be easily described in detail in a report later, and more easily understood by the reader.  It also enables development of a timeline for the forensic investigation. My forensic reports follow this format.

The format is much the same as a “work breakdown structure” in the field of project management.  The “work” in this case is the forensic engineering investigation that has been “broken down” into different tasks.

Determine the before-after scenario

In checking the hypothesis, engineering investigations determine the before-after scenario (see Introduction):

1. The nature of the area the structure is in and the ground beneath the structure – the terrain, geomorphology and surficial geology of the area
2. How the structure was built initially, and its conformance to the design and construction plans
3. What took place during the failure or the accident, and,
4. The nature and extent of the damage, inadequate performance, or injuries

2. Visual Assessment

Visit and visually assess site

This step involves visiting the site as soon as possible after the failure or accident.  The professional engineer walks and pokes around the site – kicks the tires in a sense – to get a feel for where things are and the nature and extent of the damage. He visually examines exposed surfaces.  It’s a very simple task, not very technical at all, but invaluable in getting a feel for the scene and bringing the documents to life.

It helps to dictate to a smartphone what is being seen and done during the visual assessment.

Sketching and measuring what seems to be relevant is started at this early stage.  Measuring, testing, and quantifying in a number of different ways often characterizes an investigation carried out by a professional engineer.

Photograph and videotape site

Photographing and videoing the failure or accident site and the collapsed structure is an important initial step. The sooner the better before remedial work alters conditions.

Equally important is a caption or descriptive note for each photograph stating:

1. What was photographed and videoed
2. The position of the camera and the view captured
3. Why the object was photographed
4. What to look for in studying the photographs and video, and,
5. The date and time.

Interview witnesses

Interviewing witnesses to the failure or accident and the conditions existing beforehand is also an important initial step.  It should be done as soon as possible after the incident while memories are fresh and site conditions unchanged.  Record names and addresses in the event the witness must be called to testify at a hearing later.

3. Drone Photography

Describe the failure or accident from the air

This task involves taking low level aerial video of the failure or accident site with a camera fixed to a drone. Video is taken from eye level to a few 10s of metres above the site. Screen grabs or stills can be taken off the video and inserted in the report. Site plans can be easily generated from the stills.

Re-enactments of slip and fall and traffic accidents can also be photographed from different heights above the site, and also from different directions and distances. Traffic accidents or their re-enactment can also be captured with video cameras mounted on the dashboard of vehicles – dash cameras.

Copies of the video can be distributed to parties interested in the failure or accident to facilitate discussion on the telephone or via Zoom or Microsoft Teams meetings.

We can get high resolution video of sites in urban areas from Google Earth today; we can get even better from drone video.

Apps are available to plan drone video of a site several days in advance of a site visit that is several hours driving away.

I’ve taken drone video of all my sites in recent years and the coverage has proved invaluable. For example:

1. It solved a road re-aligment problem: Drone video demonstrated what went wrong during design and construction,
2. Aerial video enabled me to identify the cause of a retaining wall failure,
3. Drone video helped me assess the depth of the water table beneath a fuel oil contaminated site – I was surprised at what I saw,
4. Low level video pointed the finger at the likely cause of a nail gun accident, and,
5. Drone video showed how poor land drainage is causing a dangerous situation for kids in the winter time.

4. Field Investigations

Describe the failure or accident

This task records what happened during the failure or accident based on the comments of the witnesses interviewed and information from the documents.  Interviewing people who were there, and saw or experienced the failure if it was a sudden collapse of a structure, or an accident, is particularly valuable to the description.

Survey and document the damage to the structure

This stage involves recording the damaged condition of the structure that has collapsed or does not perform properly.  This is done with tasks such as the following:

1. A visual examination and description of the structure’s condition,
2. Measuring the extent and location of the damage, and,
3. Photographing and videoing the damage.

These tasks should be carried out as soon as possible after the failure before data and evidence are altered or lost.  The information enables a before-after comparison to be made after the next task is completed.  This type of comparison is often helpful as noted.

Determine how the structure was built

This stage determines how the structure was built and whether or not it conformed to the design.  Also, whether or not the design and construction conformed to the standards of the day.  This information is obtained from the design and construction plans.  Also from research of building codes and industry guidelines existing at the time and checking these against the structure on site.  Tasks involved in this step include the following:

1. Obtaining copies of the design and construction drawings – often quite similar
2. Checking that the design conforms to the building code and good engineering practice
3. Checking that the construction drawings conform to the design
4. Obtaining a copy of the as-built drawings – drawings that record changes made during construction for various reasons
5. Checking that the existing structure conforms to the as-built drawings.  This involves examining and measuring the different components of the structure.  It often involves taking things apart or using remote sensing techniques to detect what is below the surface.  To facilitate this examination, drawings of the damage might be superimposed on the as-built drawings.  This superimposing would eventually be done during the data analysis (see below)
6. In the absence of drawings – often the case for older structures – measure the structure and prepare drawings, and then superimpose sketches of the damage

How many of these tasks are carried out and in what detail depends on the situation, the structure, and the failure.  Sometimes very little of the above is done.  Sometimes it’s enough just to measure and prepare sketches of the damage and view and study the structure with these sketches in hand.

Determine the site conditions

The site is the area where the structure is located including other structures nearby.

The site conditions of interest at this stage of the forensic engineering investigation include:

1. The lay of the land, the terrain, the topography
2. Surface features like bedrock exposures, sinkholes, and wet land
3. Drainage features like ponds, lakes, and water courses (hydrology)
4. Subsurface and foundation soil and rock conditions (geotechnology)
5. Groundwater conditions (hydrogeology)

Investigating and determining site conditions includes:

1. Photographing and videoing the site
2. Aerial photography, drone video and map making
3. Topographic and contour surveys
4. Drainage and groundwater studies
5. Geotechnical and foundation soil and rock investigations
6. Environmental assessments
7. Field tests like skid resistance tests, plate load tests and pile load tests
8. Accident reconstruction

Detailed topographic and elevation surveys are usually made when the failure of a building or a civil engineering structure, or the cause of an accident, is thought to involve the terrain in which the site is located.

Drainage studies (hydrology, hydrogeology) are made when surface or groundwater may have been a factor in a failure or an accident.

Geotechnical and foundation investigations may be necessary if the cause of the failure of a structure appears to be in the foundations or the subsurface soils.

Full scale field tests and accident reconstruction may be carried out.  This is done when these methods are assessed as the most reliable means of gathering data on the effects of the terrain, and features in it, on the failure or the accident.

Slip, trip and fall accidents

Almost all of what is done and described above at the site of a structure’s failure:

1. Document review
2. Visual assessment
3. Drone video
4. Field investigations

is carried out at the sites of slip, trip and fall accidents. The structure in this case is the person’s body that collapsed in every sense of the word – was caused to fall down, often by something at the site.

I tripped one time because of a 1″ to 2″ difference in the height of a curb – not my fault. Another time I stood on my dog’s lease so she couldn’t run off. However, she had a mind of her own and dashed off jerking the lease from under me and causing me to fall down/collapse/fail, hard – my fault.

In addition to the usual field and site investigations, the skid resistance of the surface where a person slipped and fell is measured – the coefficient of friction in high school physics. There is a standard of care for the procedure that is reflected in a basic field investigation as outlined above – going from the simple to the more accurate.

5. Laboratory Investigations

At this stage in the investigation, it is sometimes necessary to carry out laboratory tests.  These would determine the chemical, physical, mechanical, strength, and/or drainage properties of materials used in construction at the site of a failure or an accident.  It might be necessary to analyse the toxic fumes emitted by a compound or product used in construction.

Typical materials used in construction are soil, rock, steel, concrete, wood, plastic, adhesives, asphalt, and masonry products.

Composite materials like asphalt or reinforced concrete can be taken apart in a laboratory to determine how the material was formed.  For example, the location, type, and size of reinforcing steel in a reinforced concrete slab that failed.

6. Research

Desk studies and leg work

To some extent, research studies during a forensic engineering investigation – desk studies in some engineering disciplines – are on-going like document review.

The work often involves literature searches, telephone and internet work, and leg work to sources outside the office like libraries and the offices of persons to interview and consult with.

It also involves research and study of aspects of the engineering investigation that have assumed some relevance.  For example,

1. Past mining activity in an area,
2. The standard of care at the time the structure was designed and constructed,
3. The shrinkage and compressive properties of a fill material, and,
4. The different modes of failure of a soil-steel bridge.

Research also identifies and gathers together all information in appropriate categories relevant to the investigation (see Document Review above).  This would be information missing from the documents provided by counsel or the claims manager.  Information like original construction and as-built drawings, geotechnical and environmental reports, and published mapping of the area.  Availability of the material would be determined and copies obtained if possible.

Also during this step in the forensic investigation the need is identified for additional engineering and scientific specialists to investigate some aspect of the failure, and to study relevant findings.  Specialists would be identified, contacted, and conferred with about their possible contribution, and retained if necessary.

Identify building codes and industry guidelines

Of particular importance during the research stage would be the identification of building codes and industry guidelines.  Also the standard of care followed at some period relevant to the design and construction of the failed structure, or the structure involved in the personal injury accident.

Identify applicable government and industry codes, standards, regulations, and guidelines.  Include national and international codes that are relevant to the failure or accident and relied on locally.  Search and identify technical papers and state-of-the-art reports that relate to the problem and review this material.

Identify standard of care

This could be an important task during a forensic engineering investigation if the findings might be presented during a more formal dispute resolution process or at trial.

The standard of care is the standard commonly applied by professionals or other workers practicing the same discipline or trade in the same area at the time the structure(s) was designed and constructed that was involved in the failure or accident.

Identifying the standard can be quite simple or very involved and time consuming.  It involves interviewing other professional engineers and/or workers practicing in the area at the time the structure was designed and constructed to determine the procedures they followed and the standards they employed.  If there is wide variance you would speak with more people until you feel satisfied you know the average.

If there were two small firms practicing in the area at the time then it’s easy. For example, a soil-steel bridge failure that I investigated.

On the other hand, as in another case of mine, if there are 11 different types of firms and associations playing a part in the design and construction process associated with a failure or accident – providing different products and services – then it’s difficult and time consuming.  You would need to identify and speak with a number of representatives of each type of firm and association – potentially dozens of people – to be satisfied you understand the standard followed at the time.

7. Follow-up Investigations

This task of carrying out one or more follow-up investigations results from the need to “follow the evidence”.  This concept hardly needs explaining to counsel and claims managers.  It is equally important in a forensic investigation. 

Data will be gathered and evidence uncovered during a previous investigation that suggests other things should be investigated.  This would be like cross-examination during discovery uncovering evidence that suggests a new line of questioning.

Implicit in the fact that there might be evidence that should be followed up is the possibility that the initial hypothesis on the cause of the failure or accident might need to be revised or rejected completely.

The possibility of the need for follow-up investigations is a fact of life during forensic engineering investigations.

8. Data Analysis

Lots of data is good but you’ve got to do something with the data – draw meaning from it as to the cause of the failure or accident. This is what the dispute resolution process or a claim manager wants.

Data from one stage looked at critically

In analysing and reasoning to a conclusion, the data from any one stage of the investigation is looked at critically – taken apart, in a sense – and each part looked at carefully and how they are related and interact.

Identify typical modes of failure?

The data is also studied to see if it is characteristic of a mode of failure or a cause based on past experience or a mathematical calculation.  Professional engineers have identified and published typical modes of failure for the various structures in the built environment.  These are available for review and guidance to the forensic engineer during a forensic investigation.

Data from other stages looked at critically and for corroboration

The data from other stages of the forensic investigation are similarly looked at, and also studied to see if there is corroboration of conclusions between stages.  Pattern is looked for within individual data and amongst different sets of data.  And if there is a pattern, considering if it is typical of a known cause/mode of failure.

Draw conclusions and confirm, revise, or refute hypothesis

At some point, conclusions are drawn from the analysis and the hypothesis confirmed, revised, or refuted.  If revised or refuted then a new hypothesis is formed and this investigated with follow-up forensic investigations.

If the initial hypothesis is confirmed then the cause of a failure or accident has been identified and an opinion can be formed.

Document reasoning

At all points in the analysis the reasoning followed is documented and the basis of the conclusions recorded.

Easy analysis

Sometimes the data analysis and development of an opinion is quite easy.  For example, in one of my investigations when field work uncovered a concrete floor slab that was supported by irregularly spaced columns. This type of slab beneath a structure was meant to be uniformly supported.  In this case it was easy to hold the opinion that the floor slab was inadequately supported.

Complex analysis

At other times it’s complex.  For example, when there are more than 20 possible modes of failure for the collapse of a soil-steel bridge.  When the collapsed bridge is not available to examine, then the available data must be analysed for each mode and the cause identified by a process of elimination.

Mysterious analysis

Sometimes it’s mysterious.  Why is there a toxic odour in the concrete enclosed lower level of a structure and the lighter-than-air fumes are not detected in the timber-framed upper levels?  A chance remark about timber structures “breathing” – are more pervious in engineering terms – solves the mystery as to cause.  The fumes in the upper levels diffuse through the exterior timber walls to the outside of the structure, and also through open doors and windows.

9. Draw Conclusions

In some ways this is the easy part. You look and see if data collected from an investigative task points to the cause of the failure or accident. You then check the data from another task for an indication of cause. And still another. Etc. You cross-check causes. Is there agreement amongest the causes – a little a lot? Does the cause from one set of data support the cause from another? Is a common cause emerging? Are conflicting causes emerging? What is the preponderance of the causes pointing to as the cause of the structure’s failure or the person’s injury? How does this conclusion fit with published findings of cause of similar failures or accidents? At some point you stop – when you’re comfortable with your findings.

10. Form Opinion

At this stage in a forensic engineering investigation, your view of cause forms in your mind. It slowly appears in your head as you analyse the data, reason and draw conclusions. You then tell the listener or the reader your opinion of cause and the basis for your view.

11. Repair and remediation

Often times near the completion of a forensic engineering investigation there is a need to plan and design repair of the damaged or failed structure, and then estimate the cost of the repair.  This repair cost contributes to an evaluation of the damages claimed in a lawsuit or by an insurance policy holder.  Occasionally the repair is constructed involving engineering supervision and inspection costs, which also contribute to the damages claimed.

12. Write Report

Types of reports

The report, in particular, the written report, is an important step in a professional engineer’s investigation of a failure or accident.  It ‘s a documentation for the client and the dispute resolution process:

• of the methods used during the investigation,
• the data gathered,
• the analysis of the data, and
• the reasoning to an opinion on cause. 

It’s importance is highlighted by the fact that civil litigation rule changes in some provinces are limiting discovery of the expert.

The results of a professional engineer’s investigation are given in:

1. Oral reports,
2. A written report, and,
3. Occasionally, one or more supplementary reports

Oral report

If possible, an oral report is given the claims manager or counsel as soon after the documents are read, an initial site visit and visual assessment completed, and an initial hypothesis formed as to cause.  The report may indicate the direction the investigation appears to be heading.  This will give client an early indication as to whether the professional engineer will serve as a consulting expert or as a testifying expert.

Written report

A written report is provided at completion of the investigation.  It is prepared on instruction of counsel or the claims manager to facilitate the dispute resolution process.

Serious thought must be given to whether or not a written report is prepared, particularly for the judicial process. This is because non-technical counsel and judges are wordsmiths and benefit from well documented data and argument. They like well written reports as I have found on more than one occasion.  Else why are civil procedure rules being struck to encourage the preparation of reports and limit expert discovery?  I’m sure to save time and money but I also suspect because the judicial system likes a well written report.

For example, I know of two cases where junior counsel decided against well prepared reports: 

In the one case because of the perceived expense by counsel – and yet it was the first thing the judge asked for. Counsel’s case struggled thereafter, cost more, and may have resulted in significantly lower damages being awarded.

In the second case, counsel submitted a report containing the results of interviews.  The interviews resulted in a poorly prepared report because there was no evidence to validate the interviews which I understand constitutes hearsay in law.  Counsel neglected to call witnesses supporting the hearsay evidence and lost his case. 

Both cases seemed to be open and shut for the parties involved, if well written reports had been prepared.

Supplementary reports

The need for supplementary reports might depend on whether or not new evidence is found during discovery, follow-up investigations, or presented in rebuttal reports. Supplementary reports might use appropriate graphics, models and demonstrations to better explain the investigation and findings.

Report outline

The outline of a report will vary depending on the nature of the failure or accident and the extent of the investigation.  Many will be in chronological order, generally in the order of the tasks carried out during the investigation.  The process is a series of investigations and follow-up investigations each of which consist of different tasks.  My reports generally:

1. Describe each task in chronological order,
2. State the reason for carrying out each task,
3. Identify the data obtained from each task,
4. Analyse the data and the extent to which it supports other data and the initial hypothesis as to the cause of the failure or accident,
5. If necessary, revise the hypothesis,
6. If applicable, report on the analysis arising from follow-up investigations to confirm a final hypothesis,
7. Draw conclusions, and,
8. Form an opinion.

***

(An earlier update of this blog posted in 2012 identifies investigative tasks like assessing the standard of care existing at the time a structure was designed and constructed or an accident happened.

(The update was actually prompted by a long and difficult assessment of the standard of care that I carried out in a case. I realized that assessing the standard was an important and sometimes difficult step in a forensic engineering investigation.

(The update also provides sources in the following References for follow-up and gives data in an Appendix on the difficulty of estimating the cost of forensic engineering investigation)

References

The foregoing is based on several sources in addition to my own experience.  The citations are not complete:

1. ASCE, American Society of Civil Engineering, Guidelines for failure investigation, 1989
2. ASCE, Guidelines for forensic engineering practice, ed., Gary L. Lewis, 2003
3. ASCE, Guide to investigation of structural failure, Jack R. Janney, 1986
4. Personal communication, Jack Osmond, NSPL, Affinity Contracting, Halifax
5. Meyer, Carl, ed., Expert Witnessing; Explaining and Understanding Science, 1999
6. Steps in the civil litigation process, posted August 28, 2012
7. The cost of forensic engineering investigation, posted November 1, 2012
8. ASFE, Association of Soil and Foundation Engineers, Expert: A guide to forensic engineering and service as an expert witness, 1985
9. Ratay, Robert T., ed., Forensic Structural Engineering Handbook, McGraw Hill, 2000
10. Day, Robert W., Forensic Geotechnical and Foundation Engineering, McGraw Hill, 1999
11. What’s in “…the built environment” and how many ways can it fail? Posted July 8, 2020
12. Catling, Christopher and Bahn, Paul, Forensic Archaeology, pages 226 and 227 in The Complete Practical Encyclopedia of Archaeology, 506 pp, Hermes House 2013. The first 174 pages on archaeological digging methods are relevant to forensic geotechnical engineering
13. Cooper, Chris, Eyewitness Forensic Science, DK Publishing 2008

Appendix

(The following is adapted from a posting to this blog site www.ericjorden.com/blog on November 1, 2012 entitled, “The cost of forensic engineering investigation”)

Difficulty estimating the cost of forensic engineering investigation in Atlantic Canada (the items in bold are the main steps in a forensic engineering investigation).

The following is a subjective assessment of the difficulty estimating the costs of the steps in the forensic engineering investigative process (see foregoing item).  The more difficult the step the less accurate the estimate.

The cost assessment at the start of an investigation assumes the request is made of a professional engineer after he has been contacted, the failure briefly described, and the documents identified that counsel will provide.

Also, like in estimating the cost of a project in Project Management, the costs are approximate at the beginning of a project, get better as the project goes to completion and are good near the end.

The assessment is based on my experience in the forensic engineering investigation of failures in the built and natural environments, and fatalities and personal injury accidents in Atlantic Canada and overseas:

Difficulty estimating costs

1. Document review ………………………..………………… Easy
2. Visual assessment
3. Visit and visually assess site …………………………….. Fairly easy
4. Photograph and videotape site …………………………. Fairly easy
5. Interview witnesses ………………………………………… Difficult
6. Field investigations
7. Describe the failure or accident………………… ……. Fairly easy
8. Survey and document damage to the structure … Fairly difficult
9. Determine how the structure was built ……………. Easy to difficult
10. Determine the site conditions ……….………………… Very difficult
11. Laboratory investigations ……………………… …… Very difficult
12. Research
13. Desk studies and leg work ……………………………….. Difficult
14. Identify codes ………………………….………………………. Fairly easy
15. Identify standard of care ……………….…………………. Difficult to very difficult
16. Follow-up investigations ………………………………. Impossible
17. Data analysis and formulation of opinion ……. Very difficult
18. Repair and remediation ………………………,…..…… Difficult
19. Report …………………………………………………………… Difficult

Add to this difficulty of estimating the costs of a forensic engineering investigation, the difficulty of estimating the costs of the role of the expert in the different stages of the civil litigation process.  This compounds the problem further for counsel and the expert.

For example, how, at the start of an action, do you estimate the cost of answering the questions posed under Rule 55 (in Nova Scotia) not knowing how many there will be nor their complexity?

I was asked in a case not too long ago to answer 46 numbered questions submitted by opposing counsel.  On counting, and including important sub-questions, there were actually 77 questions.  The cost of answering these questions was approximately 13% of the total cost of my involvement as an expert in this litigation.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. November 27, 2022 ejorden@eastlink.ca)   

I thought to bundle the blogs that have a forensic investigation theme, like I’ve done in bundling other themes. I used these key words in the search of my blog site. I forgot that my blog site was all about the nature and methods of this type of engineering work and that there would be many blogs with this theme. I stopped after I got a list of three dozen blogs with more that could be added! I just ground to a halt.

There was purpose to my madness but my good intentions went off the rails. I wanted to help a client get a feel for what’s involved in this specific area of forensic activity – forensic investigation. But spare them the blogs that pursue some of the nuances of forensic work, a total of 285 to date. Focus on the nuts and bolts while the client gets up to speed.

I came out of it with a good feeling though. I realized I’m doing what I set out to do 10 years ago – talk about forensic work as it says in the masthead above. A simple qualifying word or two might have reduced the three dozen size bundle – a little tweaking can go a long way.

It is interesting though, that an investigative process like forensic work has so many little asides resulting in 285 blogs so far. Realizing this might have scared me away 10 years ago from trying to write about it.

I’m glad I didn’t because I’ve learned a lot about how to explain the work I do – while soldiering through the overwhelming parts. My work, and others like me, help readers know about the engineering techniques available for resolving the disputes that land on their desks.

***

(For example, I believe that simple terrain analysis by a surficial geologist could have reduced the risk of losing those five lives on the highway in British Columbia that was in the news again recently.

Surficial geologists map the different types of soils in an area as deposited by the glaciers many 1,000s of years ago. Terrain analysis identifies features in the terrain relevant to a problem that’s being investigated. Geotechnical engineers measure the physical properties of the soils in the different features.

The risk of landslides along a stretch of highway would be the outcome of this simple process. Signs would then be posted alerting drivers to the risk. It’s not rocket science.

See an informative blog I posted last year that was prompted by the loss of life on the BC highway: Mudslide Zone! November 21, 2021)

***

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. October 28, 2022 ejorden@eastlink.ca)   

To echo David Stockwood in Civil Litigation, a Practical Handbook: most clients are unfamiliar with the tasks involved in an investigation of the cause of a failure or accident in the built environment. They are also unfamiliar, and shocked, by the cost. (Ref. 1, 2) Nor are they aware that the forensic engineering work may not find a cause that is in their interest.

This is echoed further by Ron Pizzo, Pink Larkin Law: a forensic engineer just doesn’t know the cause of a problem when asked – a lot of engineering investigation is necessary beforehand. (Ref. 3)

And finally, as required by common law, experts provide objective, unbiased opinion evidence in relation only to matters within their expertise. (Ref. 1)

Some investigations quickly arrive at the cause of a problem – some after the forensic engineer does little more than visually examine the scene of an accident or failure. But not all. The spoiler is the need for the forensic engineer to follow-the- evidence.

***

These facts came to mind recently when I sensed that a client thought my engineering investigation would support his view that he had an earthworks problem. And another, that I would just issue an engineering report as needed, without much work on my part. This problem has often been experienced by a colleague in a related civil engineering field. (Ref. 4)

To echo Stockwood again, it’s necessary to explain the “facts of life” about forensic work at an early stage. And, of course, using a delicate touch so the injured party does not become discouraged from learning what caused his injury or failure. (Ref. 1)

I know what he’s talking about like I’m sure many of you. Those of us in forensic engineering and readers in dispute resolution and claim settlement must be understanding and clear in explaining the facts of life.

References

1. Stockwood, Q.C., David, Civil Litigation, a Practical Handbook, 5th ed., Thomson Carswell, 2004
2. Principles governing the cost control of dispute resolution and claim settlement involving experts. Posted July 30, 2019 and updated September 24, 2020 and March 18, 2021
3. Pizzo, Ron, Pink Larkin Law, “…lot of preparation beforehand – a lawyer just doesn’t walk into court” as stated during the Atlantic Provinces Trial Lawyers Association conference, Halifax 2016, It’s All Wrongful: Death, Dismissal, Conviction & More.
4. Conversation with Jamie Yates, P.Eng, consulting professional engineer, Fall River, Nova Scotia 2022

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. October 20, 2022 ejorden@eastlink.ca)   

I’ve been posting blogs on the nature and methods of forensic work and expert services for 10 years. The blogs – two or three a month – go to people who might need to know how the cause of an accident or failure in the built environment is determined. People like:

• Claims managers
• Adjusters
• Lawyers
• Engineers
• Architects, and,
• A few others in related fields

I have not been posting to the actual person who might be injured in an accident, like a slip and fall, or whose property might be damaged. Yet these are the people who bear the financial burden and need to know something about forensic work. What forensic workers do and why.

***

The penny dropped recently when a property owner telephoned about an earthworks problem he saw in his area. I had been recommended by another engineer, and the owner had also visited my web and blog sites. “Impressive”, he said. Nice to hear.

I tell you these things so you can know the good footing we started off on – before things started to unravel. When you’re up, the only way is down. (Ref. 1)

***

He told me about his problem on the telephone and then we arranged to meet at his property. He was concerned about earthworks on his neighbour’s property affecting the structures and ground on his. His property was level then dropped off to his neighbour’s.

I quickly saw during my visual assessment that I had to do standard things like:

• Research published mapping of the area,
• Locate his property line,
• Get some low level aerial photography from a drone, and,
• Dig some test pits.

We also looked at some Google earth aerial photography that the property owner got up on his laptop that was the same as I got shortly after he telephoned me.

All of the above tasks went through my mind – in a heart beat – as we walked over his property because they are standard tasks in a forensic investigation. He wasn’t likely to need much more investigation than this to assess the earthworks problem as he perceived it.

The data from these tasks would define the location and depth of the earthworks with respect to his property line. I would also get the slope of the property. Most of this data would be numerical – in numbers like engineers like. The earthworks’ problem would be quantified.

***

After I did the heart-beat assessment I asked questions about one large structure on his property located back from the location of the earthworks. It was far enough away that it was unlikely to be a factor in the earthworks problem. But it was there and it was big and it was in order to take some interest.

Time passed and with my initial assessment completed I left. I noted that I would research published mapping, book drone photography and get back to him.

***

I got back to him after the weekend and met him at his property, only to be told he didn’t need my services, that he was “going another way”. It turns out that my questions about the large structure on his property seemed at the expense of greater interest in his earthworks problem.

He does need a thorough and objective forensic investigation to define the nature and scope of the earthworks problem on his property as he perceives it. I saw what needed to be done as soon as I walked across his property, but he didn’t because I didn’t say.

If I made a mistake in this situation, it was neglecting to describe in detail the investigation needed to define his problem and the cause of it. Then, and only then, take interest in the big structure on his property.

Forensic investigation was new to him – he would have more knowledge of his annual medical checkup courtesy of Dr. Google. I dropped the ball in not realizing this.

***

I must look into posting my blogs to the general populace, the people who bear the financial burden and need to know what they get for their money.

Add them to the above list. Help them to know about the nature and methods of forensic work. Also, how quickly an experienced forensic engineer can sometimes know what needs to be done to investigate a personal injury or a structural failure.

Reference

1. I learned long ago from an engineering friend, John L’Aventure, that when you’re down, the only way is up. John knew. He got into fish farming after practicing engineering for a few years. At one point one of his four fish cages was breached by seals and he lost 1,000s of salmon. It took him five years to get back on his feet.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. October 11, 2022 ejorden@eastlink.ca)   

I thought to gather these blogs together after posting the first one on bias in police work. There are good references attached to some of blogs.

Bias is alive and well and lurking in the shadows but, almost without exception, not deliberate by forensic workers.

1. Is bias alive and well in police investigation? Posted September 20, 2022 This blog explains sneaky, implicit bias and offers some comment on how to deal with it plus some references. I’m certain the police officer’s comment prompting the blog was of the sneaky kind – he just didn’t know he’d been had.
2. Ridding peer review of potential bias. Posted December 30, 2019 You have a choice on how to do this as explained in the blog. The six (6) choices go from best to least. There are also a few good references referred to in the blog.
3. Are experts being broadsided by bias, unbeknownst to them? Posted April 12, 2018 I summarize bias as explained by three Toronto police officers at the two day Expert Witness Forum East in 2018. They identified eight (8) categories of bias relevant to forensic work then focused on two. Examples of bias are given including a serious one in Nova Scotia. This was a good conference; I was pleased to be invited to give a talk on the Principles Governing Cost Control in forensic work. (Ref. 1)
4. Expert witness forum looks at bias and other touchy subjects in forensic work. Posted March 8, 2018 I give a brief summary of what took place at this conference and elaborate later in a detailed blog in April, 2018 (Item #3 above). I think what I was doing with this blog back in March, 2018 was giving readers a heads-up as soon as possible of a good conference. The blog does inform on bias and is worth taking a look.
5. Biased experts cured with a soak in the “hot tub”. Posted January 31, 2017 This is a good read on an excellent method for ridding dispute resolution and insurance claim settlement of bias. The great success with this method in Australia, and the watchful eyes of newspapers like The National Post, will make it happen.
6. Would I be perceived as biased? Posted July 2, 2014 I raise an interesting question in this blog: Would I be perceived as biased if I told counsel about literature that discusses both the technical and non-technical issues – including legal issues – of a problem in the built environment? Particularly if the literature proved to be of considerable legal interest and little or no technical interest. Hmmm? The question came up on the occasion of my researching the literature on the properties of a material used in construction in the built environment.

References

1. Principles governing the cost control of dispute resolution and claim settlement involving experts. Posted July 30, 2019 with updates added September 24, 2020, March 18, 2021 and December 30, 2021.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. September 27, 2022 ejorden@eastlink.ca)   

I wondered this when I overheard a police officer comment, “The truth is somewhere in between”. He was investigating an incident and getting statements from different parties about what happened. Based on his comment, there didn’t seem to be any room in his thinking for one party’s view to be correct about what happened. I can’t say if he came with that mind-set – that’s the way all police officer’s think – or just how he thinks.

His comment is an example of implicit bias as discussed in depth by three Toronto police officers at an expert witness conference. (Refs 1, 2) The officers described implicit bias and explained how to deal with it. The two days of lectures on bias were excellent.

(I attended this conference and gave an invited talk on the principles governing cost control in dispute resolution. (Ref. 3)

Implicit can be defined as capable of being understood from something else though unexpressed. (Ref. 4) The problem is the something else is not explained. Is it reliable or no?

If the something else is the result of an analysis of the evidence leading to a conclusion like the “truth is in the middle”, that’s fine. But, generally, police officers on-the-run are not analysing evidence, they’re focusing on collecting it for analysis later by others.

And analysis itself is an exacting process. Think the scientific method. Also the two year course on data analysis offered by a college in Ontario – that’s two years learning the principles of data and evidence analysis. (Ref. 5)

I met a Nigerian chap who is in Canada enrolled in the two year course. He’s learning how to analyse data, facts and evidence to see where they lead. I mentioned the scientific method and he was quick to acknowledge that was part of it. I don’t think the police train like this, as a rule, to analyse evidence and statements by parties to an incident to see where the truth lies.

I’m certain police officers are trained in the collection of evidence, and analyzing it on-the-go in some situations. Witness what went on in Saskatchewan as I was writing this – police officers were analyzing evidence on-the-fly trying to find a mass murderer. But analyzing evidence as they collect it is not the rule.

You collect and analyse evidence by being thorough and objective, and on guard against implicit bias – a cardinal rule in forensic engineering investigation as carried out by experts.

We deal with implicit bias according to the Toronto police by: (Ref. 1)

1. Understanding implicit bias
2. Identifying the bias
3. Reducing it
4. Mitigating for the bias of your audience

***

I think implicit bias is alive and well but well suppressed by investigating police officers. It just manages to poke it’s head up from time to time. Bias saw the light of day for a moment in the comment by the chap I chanced to overhear but it’s not the rule. I know this to be true – police objectivity – from my 19 years volunteering with a police victim services unit and working with police officers.

References

1. Virji, Aly, Staff Sergeant and Moosi, S. Ali, Constable, Toronto Police Service, Addressing Implicit Bias On and Off the Stand, 3rd Annual Expert Witness Forum East, Toronto, February 27, 2018
2. Duncan, Peter, Instructor, Toronto Police Service, Addressing Implicit Bias: Interactive Session, 3rd Annual Expert Witness Forum East, Toronto, February 27, 2018
3. Principles governing the cost control of dispute resolution and claim settlement involving experts. Posted July 30, 2019. Updated September 24, 2020 and March 18, 2021
4. Merriam-Webster and Oxford Dictionaries
5. Data Analytics for Business, St. Clair College, Windsor, Ontario

Appendix

1. Expert witness forum looks at bias and other touchy subjects in forensic work. Posted March 8, 2018
2. Are experts being broadsided by bias, unbeknownst to them? Posted April 12, 2018

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. September 20, 2022 ejorden@eastlink.ca)   

I decided to gather these bundles together on realizing that if there are several blogs on a topic it’s a useful reference in civil litigation, dispute resolution and insurance claim settlement.

These bundles gather 81 blogs together on the following seven (7) topics that are useful in forensic engineering investigation and expert services in.

I quickly reviewed the blogs in putting this one together. I was struck by the thorough research and careful writing needed in blogging on the standard of care and peer review; #1, #2 and #4. If you don’t mind me saying, I worked hard to get the state-of-the-art out there on these important tasks in forensic work.

1. A Bundle of Blogs: On assessing the standard of care. Posted August 12, 2022. Contains a total of 5 blogs on the topic
2. Update: A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted April 28, 2021 Contains a total of 2 blogs
3. A Bundle of Blogs: On using visual site assessment in forensic investigation. Posted January 25, 2021 Contains 11 blogs
4. A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted November 29, 2019 Contains 7 blogs
5. A Bundle of Blogs: Aerial video of insurance and forensic sites taken with cameras mounted on drones. Posted October 31, 2019 15 blogs
6. A Bundle of Blogs: How to manage the cost of civil litigation involving experts. Posted August 31, 2017 17 Contains 17 blogs
7. A Bundle of Blogs: A civil litigation resource list on how to use forensic engineering experts. Posted November 20, 2013 Contains a total of 24 blogs
8. A Bundle of Blogs: Investigating slip, trip and fall accidents. In draft ??? 2023 Contains a total of 6 blogs at present

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. August 28, 2022 ejorden@eastlink.ca)   

I thought to gather these blogs together after drafting the most recent one on ‘Multi-expertise…’ I realized again that assessing the standard of care is usually not easy and, regardless the ease, it’s always a responsible task.

There’s a lot of my explanation and thought on this in the following blogs, and reference material with the views of others accompanying the blogs.

1. Multi-expertise is sometimes needed when assessing the standard of care and what a “reasonable person” would do. Posted July 29, 2022 I don’t think it’s a surprise that some tasks in most fields need input from more than one area of expertise or skill. This is obvious enough with a catastrophic failure in the built environment. It’s fairly obvious in some accidents causing personal injury like a nail gun accident. It’s not so much in more humble problems like that involving component failure, a house deck failure or the not-so-glamourous ground. I thought to illustrate this need for multi-expertise with this blog on two examples of humble problems.
2. What happened to the “standard of care” – the degree of care that a reasonable person should exercise? Posted June 22, 2021 This blog was prompted by a newspaper report of a building failure in Ottawa. There seemed to be glaring absences of “reasonable people” at several stages in development of this structure.
3. How the standard of care is determined when a failure or accident occurs in the built environment. Update. Posted October 30, 2020 This blog was updated to comment on the determination of the standard of care in an area that has not adopted the National Building Code (NBC). The NBC is a minimum standard for construction in the built environment. As such, it would be considered in what a reasonable person would do. This is a brief blog drawing attention to the issue noted in Blog #5 below. To be truthful, I’m not sure why I wasted your time with this blog; it’s all explained in Blog #5
4. Is there a case for a multi standard of care? No. Posted June 27, 2019 This is a good read, informative, insightful and perhaps a tad funny in the odd spot. Also, some good reading in the References and Appendix.
5. How the standard of care is determined when a failure or accident occurs in the built environment. Posted June 28, 2014 This is also a good and comprehensive read with recent updates and lots of References

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada. August 12, 2022 ejorden@eastlink.ca)   

You need an expert when assessing the standard of care and identifying what a reasonable person would do during the investigation of an accident or failure in the built environment. (Refs 1) For example, an engineer who has investigated the cause of problems like the following:

• Personal injury accidents
• Component and catastrophic failure of structures
• Ground subsidence
• Landslides
• Flooding
• Potholes or tire-worn tracks in roads
• Etc.

But what do you do when the problem requires an expert with two or more areas of expertise? For example, engineering design expertise and tradesman carpenter experience – like in house construction.

I thought this recently when repairing my balcony that is made of timber planks. And another time when underpinning a deck supported on a waste fill. In both cases I would need an engineer with tradesman experience to assess if what I did was reasonable – a slightly unusual combo of expertise.

Hmmmm…?

Repairing My Timber Deck

The tops of the outer ends of the inner two beams of four had rotted and no longer supported the deck planks properly. The beams had failed after 18 years. Why the inner beams and not the outer two? Also, why the tops of the outer ends of the beams and not the tops of the inner ends fastened to the house?

It was an easy call. It was a wetter environment at the tops of the outer ends of the beams beneath a lovely magnolia tree. The beams came to the end of their useful life for the environment they were in. All materials have a life in the built environment that engineers consider when designing.

Fixing the problem was an easy call too. Just replace the deteriorated beams with new ones. However, there is a difference in construction time and cost depending on how you do this.

The simplest, quickest, least expensive way involves installing new beams alongside the old ones. The old ones will rot away in time and the weight of the deck (dead load) and me and my family and friends walking around up there (live load) will slowly transfer to the new beams.

The more involved, slower, more expensive but possibly more conventional way involves temporarily underpinning the deck, removing the rotting beams and installing new ones.

Both repair methods will work but leaving the rotting beams in place is a tad unconventional. What would a reasonable person do, as required in a standard of care assessment? And where do I find such a person with lots of experience in both engineering and hands-on deck building?

I believe the bias in this situation would be to a person who has built a few decks but with some engineering experience.

Underpinning a Timber Deck

A friend’s deck had settled several inches over the years. The house and deck were built maybe 30 years ago. The wood deck and joists were supported on beams that in turn were supported by timber posts resting on concrete blocks. Typical residential deck construction.

Atypical was the concrete blocks resting on filled ground, not dense, natural ground typical of most of Nova Scotia. To make matters worse, the fill was a mixture of boulders, soil and tree stumps typical of waste material from a construction site. Fill, unlike natural ground settles over time; waste fill settles a lot.

But to give fill it’s due, the settlement decreases over time and becomes negligible in engineering terms. The time depends on a lot of factors including the type of fill and the natural ground below. I would expect a waste material like on my friend’s property to settle a lot and continue for a long time.

Measurements indicated the deck surface had settled about six (6″) inches midway between the corners at the rear. Examination of the bottom of the posts found a gap between the bottom and the top of the concrete blocks. The blocks had settled away from the bottom of posts as the waste fill settled. The gap was two (2″) at the midway post at the rear. Adding the size of the gap to the settlement of the deck indicated the surface of the waste fill had settled about eight (8″) inches in 30 years.

Fixing it was simple and easy, just install longer posts resting on the concrete blocks – a simple underpinning operation in engineering. But, what if the waste fill was still settling after 30 years and we come back a few months later and find gaps beneath the underpinning posts again?

Still an easy fix, install steel jack posts that can be adjusted in the future. The need for this adjustment would be apparent if the posts wobbled a little when examined later. Jack posts have a threaded section that can be screwed in or out like a big bolt – up or down in this situation – to remove any wobble.

But this requires periodic examination of the posts in the future. This could be avoided by excavating the waste fill at each post and supporting each concrete block on the natural ground below.

Another fix but a very expensive one, and a bit scary too because waste fills are unstable if you disturb them even after 30 years. Experienced engineers would leave the fill alone – let sleeping dogs lie – and experienced tradesmen certain to as well.

I believe the bias in this situation would be to a person with an engineering background who has built two or three decks.

***

Final thought on multi-expertise experts

The examples above are fairly simple but there are more complicated failures out there that require a team of expertise. What to do? For sure, be careful because there are those who claim more expertise than they’ve got.

The approach in engineering is to retain an engineer who would be the principal expert. S/he would identify the areas where additional expertise is needed and search for people in those areas and hire them. The principal engineer would then work with the sub-consultants/experts in determining cause. I did that when investigating the cause of a nail gun accident and also an old fuel oil spill.

References

1. How the standard of care is determined when a failure or accident occurs in the built environment. Posted June 28, 2014 (The posted blog has been updated to October 30, 2020 as noted in the blog) A good read with lots of references.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada July 29, 2022 ejorden@eastlink.ca)