Steps in the forensic engineering investigative process



Counsel benefits when they have some knowledge of the forensic engineering investigative process that is followed by an expert.  The process determines why a structure failed or an accident happened.  The process results in a thorough investigation leading to an objective opinion rendered with considerable certainty.

This item identifies and describes the steps in the process. The process is followed regardless as to whether the professional engineer is retained as a consulting expert or a testifying expert.

A structure is anything in the built environment, including alterations of the natural environment like highway embankments and earth and rock slopes.  A failure can involve total collapse of a structure or its inadequate performance.

There are three fundamental components to the forensic engineering investigative process:

  • Acquisition of data
  • Analysis of data
  • Presentation of conclusions and opinions

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. Document Review
  2. Visual Assessment
  3. Field Investigations
  4. Laboratory Investigations
  5. Research
  6. Follow-up Investigations
  7. Data Analysis and Formulation of Opinion
  8. Report

Field investigations can be broken down further:

  1. Describe the Failure or Accident
  2. Survey and Document the Damage to the Structure
  3. Determine how the Structure is Built
  4. Determine the Site Conditions

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

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

1. Document Review

Documents provided by counsel during the initial briefing are important in a forensic engineering investigation.  They sometimes provide the only data available to an engineer investigating a failure. Documents include items like the following:

  1. Client narrative
  2. Discovery transcripts
  3. Text
  4. Drawings and maps
  5. Photographs
  6. Maintenace records

Additional published documents almost always 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
  11. Environmental reports

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

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

In checking the hypothesis, engineering investigations determine:

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

2. Visual Assessment

This step involves visiting the site as soon as possible after the failure or accident, walking and poking around the site to get a feel for where things are and the nature and extent of the damage, and examining 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.

Measuring in a number of different ways characterizes the investigation carried out by professional engineers.

3. Field Investigations

Describe the Failure or Accident

This step involves learning what happened – getting a description of the failure or accident by interviewing witnesses.  This discription may be gleamed from the documents but talking with people who were there and saw or experienced the failure – particularly if it was a sudden collapse of a structure, or an accident, is much better.

Survey and Document the Damage to the Structure

This step involves recording the damaged condition of the structure that has collapsed or does not perform properly.  The condition is recorded by means of 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 videotaping the damage.

This should be done as soon as possible after the failure before data and evidence are altered or lost.  The information enables a before-after comparision to be made after the next step is completed.  This type of comparison is often helpful.

Determine how the Structure is Built

How the structure is built, whether or not it comforms to the design, and the adequacy of the design is determined in this step.  Also, whether or not the design reflects the standards of the day.  This information is obtained from various plans and research of standards 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 the design that it conforms to 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 due to 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 supepimpose 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 the structure is on and the terrain beyond the site including other structures.

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

  1. The lay of the land; 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
  5. Groundwater conditions (hydrogeology)

Investigation of site conditions includes:

  1. Photographing and videotaping the site
  2. Aerial photography and map making
  3. Topographic and elevation/contour surveys
  4. Drainage studies
  5. Geotechnical and foundation soil and rock investigations
  6. Full scale field tests like plate load tests and pile load tests
  7. 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) 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.

4. Laboratory Investigations

It is often necessary to carry out laboratory tests to 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 measure 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.

5. Research

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

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, past mining activity in an area, the standard of care at the time the structure was designed and constructed, the shrinkage properties of a fill material, and 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 of the failure (see Document Review above).  This would be information usually not contained in the documents provided by counsel during the initial briefing.  Information like original construction and as-built drawings, geotechnical and environmental reports, and published mapping of the area

6. 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.  It is equally important in a forensic investigation.  Data will be gathered and evidence uncovered during a previous investigation that suggests another line of enquiry should be followed up or another area investigated.  This is 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 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.

7. Data Analysis and Formulation of Opinion

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 their interaction examined.

The data is also looked at closely to see if it is characteristic of or associated with a mode of failure or a cause based on past experience and/or 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.

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 of failure.

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

If the initial hypothesis is confirmed then the cause of a failure has been identified and an opinion can stated.

Sometimes the data analysis and development of an opinion is quite easy.  For example, when field work uncovers a concrete floor slab that is supported by irregularly spaced columns and the type of slab that should be beneath the structure is required to be uniformly supported.  Then it’s easy to hold the opinion that the floor slab is inadequately supported.

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 data must be analysed for each mode and the cause identified by a process of elimination.

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 a sense, 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.

8. Report

The report, in particular, the written report, is an important step in a professional  engineer’s investigation of a failure or an accident.  It is an objective documentation for the judicial system 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 resulting in the report often replacing the discovery stage.

The results of an engineer’s investigation of a failure or an accident are presented in:

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

If possible, an oral report is given to 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 will indicate the direction the investigation appears to be leading.  This will give counsel an early indication as to whether the professional engineer will serve as a consulting expert or as a testifying expert.

A written report is provided at completion of the investigation.  It is prepared on instruction of counsel for the court and judge and submitted to counsel.

The need for supplementary reports might depend on whether or not new evidence is found during discovery, in follow-up investigations, or presented in rebuttal reports.

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 the order of the steps in the forensic engineering investigative process.  The process is a series of investigations and follow-up investigations.  My reports generally:

  1. Describe the individual investigations,
  2. State the purpose or reason for carrying out each investigation,
  3. Identify the data obtained, and,
  4. If possible, do a little preliminary analysis and reasoning and comment on the validity of the initial hypothesis.


The foregoing is based on several sources.  The citations are not complete:

  1. ASCE, 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. Mr. Jack Osmond, NSPL, Affinity Contracting, Halifax
  5. Expert Witnessing; Explaining and Understanding Science, ed., Carl Meyer, 1999
  6. Steps in the civil litigation process

Copyright 2012, Eric E. Jorden. All rights reserved




The role of a professional engineer assisting counsel during Discovery

The professional engineer as an expert witness has an important role assisting counsel at the discovery stage of civil litigation.

Discovery is a process of obtaining information from the opposing parties and their lay and expert witnesses by asking questions.

This item, one in a series, identifies and lists tasks the engineer might carry out during preparation for the questioning.  Engineers basically assist by contributing the technical component of the questions.  They also testify at discovery as experts when called on.

At the discovery stage all engineering investigation is complete, all evidence, engineering data and testimony that any party may offer at trial is known and can be fully examined by all other parties.  The cause of the engineering failure, poor structural performance, or personal injury/fatal accident has been determined.

By reviewing the total body of evidence, the parties and their counsel are able to assess the strength of their respective positions if the action proceeds to trial.

Information is obtained and the evidence reviewed by asking questions in the following ways:

  • Discoveries (ask questions)
  • Interrogatories (submit written questions)
  • Undertakings  (agree/undertake when asked to provide information, data and physical evidence later)

Prior to discovery in some jurisdictions, questions can be asked of an expert in writing by opposing parties – delivered through counsel, which must be responded to within a stipulated period of time.  For example, Rule 55 of the Civil Procedure Rules of Nova Scotia.

Discoveries are oral question-and-answer sessions under oath where each party’s counsel poses detailed questions to the other party’s witness(s), including engineering experts, about the opinions and testimony they will offer at trial.

A discovery is formal and similar to trial except it is not held in a court before a judge.  The sessions are recorded by a court reporter who transcribes the proceedings which can be used later at trial.

The role of the professional engineer at the discovery stage of the civil litigation process might involve the following:

  1. Review all technical documentation, electronic data, physical evidence, tangible exhibits, and possible demonstrative evidence on the case sworn to by the parties to the extent this information is known
  2. Confirm the technical evidence, facts, and opinions as presented by the parties
  3. Identify technical evidence and documentation that may exist and be discoverable but wasn’t noted in the Affidavit of Documents
  4. Confer with counsel about their clear understanding of the evidence from the forensic engineering investigation, the technical facts supported by the evidence, and the technical issues on which the claim, defence, and counter claims are based
  5. Identify relevant technical data and information that should be sought from parties involved in the litigation
  6. Identify engineering investigation that has not been carried out by the parties because of various constraints (e.g., omission, budget, time/schedule, site access)
  7. Suggest technical lines of questioning to counsel to obtain missing but relevant information, or to examine perceived technical mistakes or flawed reasoning by opposing lay and expert witnesses
  8. Review the forensic engineering investigation file and prepare to testify as an expert witness if presented by counsel
  9. Engage in a mock discovery with counsel, including direct and cross-examination of the professional engineer
  10. Attend and audit discovery and testimony of opposing experts and lay witnesses for technical content
  11. Assess relevance and explain technical testimony to counsel during the discovery proceedings
  12. Prepare for and testify as an expert witness on the forensic engineering investigation carried out by the professional engineer
  13. Review transcripts of the testimony of lay and expert witnesses and identify and assess relevance of unknown technical data
  14. Confer with counsel on the technical content of the transcripts
  15. Assist counsel in narrowing the technical issues to be determined at trial

Interrogatories are written questions from opposing parties to engineering experts by agreement which were not asked at discovery.  The questions must be answered within a prescribed period of time.

The role of the professional engineering assisting counsel at this stage of the discovery could involve the following:

  1. Review reports by others and assist counsel prepare written technical questions not asked at discovery
  2. Prepare written technical questions for engineering experts arising from an audit of the discovery and testimony of expert and lay witnesses
  3. As the professional engineer being discovered, research answers to the interrogatories and provide these

Undertakings are agreements by the engineering expert who is answering questions to provide answers later or copies of documents or other material.  This would be information that the engineer could not readily provide to the opposing party at the time.  The information may consist of paper documents, electronic data and physical evidence.  The engineer undertakes to provide the information within an agreed period of time.

The role of a professional engineer at this final stage of the discovery is well defined:

  1. Research and submit answers to questions, and gather together and provide documents, data and physical evidence not provided during discovery  
  2. Review transcripts of proceedings and note any technical information that may affect the engineer’s opinion

At this stage in civil litigation, the parties have presented all information on their respective positions to the court.  All the facts and engineering data are known making it an opportune time for the parties to attempt resolution of their dispute by mediation or arbitration.


  1. Stockwood, Q.C., David, Civil Litigation, A Practical Handbook, 5th ed, Thomson Carswell, 2004
  2. Steps in the civil litigation process; posted August 28, 2012
  3. The role of a professional engineer in counsel’s decision to take a case; posted, June 26, 2012
  4. The role of a professional engineer assisting counsel prepare a Notice of Claim; posted July 26, 2012
  5. The role of a professional engineer assisting counsel prepare a Statement of Claim; posted, September 11, 2012
  6. The role of a professional engineer assisting counsel prepare a Statement of Defence; posted, September 26, 2012
  7. The role of a professional engineer assisting counsel prepare an Affidavit of Documents; posted, October 4, 2012

Professional ethics and the tyranny of the bottom line. Update

Your interest as a lawyer or claims manager

You as a civil litigation lawyer or insurance claims manager have a big interest in the objectivity of the experts you retain and the opinions they render.  Ethics is an element in objectivity.  Knowing the sources of pressure on objective and ethical conduct – the bottom line is one source – guards against compromise.  Educating professional people early in their career on these issues would seem to be a good idea.

Reader’s comments on initial posting

This update reflects informative comment from three readers of the initial posting on this topic published September 17, 2012.  The initial item expressed concern – after I read two articles in an engineering periodical, about the pressure on professional engineers to do good work when being retained by others whose objective is to make money.

Professor Chris MacDonald, who blogs on business ethics, and is widely and well regarded, noted that the “problem of the employed professional” is a standard one in all the textbooks on professional ethics.  One business ethics course that he used to teach spent a couple of weeks on the problem (C. MacDonald, Phd).

Ms. Barbara Bleasdale, who lectured in a school of nursing on the east coast for more than 25 years, thinks the bottom line rules in healthcare decisions as well….and the ethical dilemma causes some nurses to leave the profession as they are not always supported in doing the right thing (B. Bleasdale, RN).

Dr. John Hughes, a retired consulting professional engineer, noted the size of the larger consulting firms today – many, many 100s of professional engineers as opposed to a few dozen a few decades ago.  He is of the view – shared by a senior colleague, John Ackerly, P.Eng. who consults to large international firms, that this does not promote responsibility for good design.  The company and it’s employed engineers are essentially sheltered behind the limited company rules.  Basically, one has to return to the small, “private company” in which each professional engineer takes responsibility for the success of the firm, including the professionalism exhibited by the employed engineer (J. Hughes, Phd).

The problem of the “employed engineer” is particularly relevant in forensic engineering.  Ethics is an element in the objectivity we must bring to our engineering investigations, and to the judicial system when we are called as experts – witness civil procedures Rule 55 in Nova Scotia.

Updated initial posting

I was initially taken by two articles in the Fall Newsletter of APENS, The Engineer, that could be summarized by the following comments: “…engineers found guilty of misconduct...” and “…skills engineering schools should teach“.

The article about skills caught my attention first.  It was entitled, The Top 5 Skills Engineering Schools Should Teach, and was written by Natalie Cornelius, P.Eng. It was admirable that Natalie took time to draw attention to skills practicing engineers need and to initiate a discussion about these.  I agree with some of what Natalie writes but not all.  She identifies the following skills:

  1. Written communicatoin
  2. Attention to detail
  3. Networking, and/or how to call someone you barely know and get information
  4. Skillful negotiation
  5. Flexibility and adaptability

I agree wholeheartedly with the first, believe the second is being addressed well enough in university now – maybe too much, and believe the remaining three are not fundamental enough for a university program in engineering.

I believe a skill that Natalie might have included was Verbal Communication.  I also believe – and this has been reinforced by the responses to my initial posting, that the awareness of engineers should be raised, as soon as possible in their careers, about professional ethics and the pressures on these.  My list of skills might look like the following:

  1. Written communication
  2. Verbal communication
  3. Professional ethics

The reason for my views on the article are beyond the scope of this posting.  But, I do think Natilie’s views on engineering curriculum could have been even more helpful if her article had also reflected the results of interviews with senior engineers in engineering disciplines, fields of practice, and life experiences other than her own.  Experienced practicing engineers of all stripes have a lot to offer the universities on what they might be doing.

The article about engineers found guilty caught my attention second.  It was entitled, Engineers who declared Lake Algo Centre Mall structurally sound, found guilty of misconduct in 2010.  This is the Elliot Lake Mall that collapsed and that I blogged about a few weeks ago (Cause of roof collapse at Elliot Lake, published July 10, 2012).  The article in the APENS newsletter was originally published in The Globe and Mail on Saturday, July 14, 2012.

It was encouraging to see APENS carry this item about professional engineers who appear to have slipped up

It’s interesting that the engineer’s misconduct had something to do with engineering design and inspection.  These were areas that I thought in my blogging were deserving of hypothesizing, particularly construction inspection.

I can’t help but think of the pressure some practicing engineers are under to do the right thing in their work.  Few if any knowingly do wrong but we are human and occasionally let our guard down and inadvertently do the wrong thing.

Those of us who are in private consulting practice learn early on to be careful of some clients – I could identify but won’t, who leverage the smallest amounts of capital to dizzying levels, and the professional engineers who are under pressure to produce inexpensive designs and are swept along in this leveraging.

I’ve thought for some time – months if not two or three years, about the subtle pressure professional engineers are under who work for commercial firms and fiscally responsible bureaucracies where the bottom line rules.  Some of these organizations are up to a 1,000 strong in professional staff.  Most professional engineers work for small and large organizations like these.  To some extent, engineering professionalism is threatened by the tyranny of the bottom line.

This conflict between the bottom line and professionalism has troubled me enough that I’ve thought to suggest to Chris MacDonald that he blog about ethics in the professions.  Chris is a professor at Ryerson University in Toronto, formerly with Saint Mary’s University, who blogs about business ethics.  Chris is extremely well recognized world wide in his field.  I think professional ethics is a fertile field for a chap like him with his insight and knowlege.  As noted above, it turns out that “the problem of the employed professional” has been recognized at universities, at least by business schools, and that Chris has taught a course on this subject.

In any event, to wrap this up, and get back to the two articles I saw in the APENS newsletter, I think a course worthy of an engineering curriculum would be one on professional ethics and the pressures on these ethics in our society.

Relevance to forensic engineering

Some of the young engineers will practice forensic engineering after they get a few decades of experience under their belts.  I can tell you that ethics plays a particularly important role in forensic engineering.  There is not a little pressure on a professional engineer to advocate for the client.  There is also the normal pressure of a human being identifying with the underdog after the cause of a failure is known.  These pressures threaten the professional engineer’s need to be objective as required by the courts.  A course in ethics would raise the young engineer’s awareness of these pressures and help him/her resist them.


  1. Cause of the roof collapse at Elliot Lake.  Blog posted July 10, 2012
  2. Professional ethics and the tyranny of the bottom line.   Blog posted September 17, 2012
  3. C. MacDonald, Phd, Ryerson University, Toronto
  4. B. Bleasdale, RN, Halifax
  5. J. Hughes, Phd, Vancouver





The role of a professional engineer assisting counsel prepare an Affidavit of Documents; 6th posting in a series

This is the 6th in a series of postings on the role of a professional engineer in the 11-step civil litigation process.

The role of a professional engineer in the preparation of an Affidavit of Documents, the 4th and final step in the Pleadings, is brief – perhaps three tasks.  It involves checking that all relevant technical and scientific documents have been included in the Affidavit.

The Pleadings consist of the following steps in the civil litigation process:

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

An Affidavit is prepared if a matter is not settled after the Statement of Defense and an exchange of letters in an attempt at a settlement.  An Affidavit of Documents affirms that each party’s relevant documents have been disclosed.  All parties prepare, swear, serve and file an Affidavit with the court.  A party must produce in its Affidavit all documents and electronic information, including technical and scientific material, that it has in its possession or control relevant to the matters in issue.

The role of the professional engineer at this stage of civil litigation might consist of carrying out the following tasks:

  1. Review Affidavit of Documents of the party who has retained the engineer and confirm that all documents relevant to the technical issues have been considered and included
  2. Identify technical documents that should exist and be disclosed by all the parties to the action
  3. Assess if an opposing party’s Affidavit of Documents is complete or deficient of documents relevant to the technical issues