Forensic Engineering - A Brief Description

TASA ID: 4541

Something goes wrong and there is a perceived failure. First question, what? Second question, what is wrong? When the “something” or the “wrong” involves technical issues, a forensic engineer may be engaged to answer the question. This brief introduction addresses forensic engineering as it relates to building issues.

What may be defined as a failure?

There are four definitions which I typically consider. The first is the inability to perform as “required.” This typically relates to a failure to conform to prevailing law, as may be embodied in building codes and regulations.

The second is the inability to perform as intended. For new buildings, intent is embodied in the building design, contracts, specifications, and later modifications.  For existing buildings, the intent may be contained in public offering statements, disclosure statements, appraisals, condition assessments, and similar documents.  Under this definition, the failure may include cost overruns, delay claims, poor construction quality, errors in design and other criteria which can be directly linked to the claims made in the documents supporting the complaint.

The third is the inability to perform as anticipated. This may be restated as issues of serviceability, usability, constructability, and maintainability. These are issues surrounding what would be expected to be provided from the product, as opposed to compliance with prevailing law, contractual agreements and design documents.

Lastly, is the inability to perform as desired and is typically the most difficult failure type to prove. It may relate to the space, profitability, aesthetics, expectations, or other anticipated or imagined benefits which were desired by the plaintiff to be provided and have now failed to materialize.

It is important to note that, what may be perceived as a failure under one of these definitions may not be a failure for all. For example, a column claimed to have been located inappropriately may be redundant and unnecessary.

The forensic engineer is first faced with the problem of determining the actual issues, as the initial perception of the problem may be a consequence of the actual failure(s), rather than the proximate cause, or may even be a contributory cause further exacerbated by other failures. Once the issues are correctly identified, there is the question of the validity of the allegations. As alluded to above, a failure to perform may not be a failure to perform as agreed. Should a failure be validated, the cause, the remediation, the cost, and often the “who” of the failure may be asked of the forensic engineer.

Buildings may “fail” for many reasons. Among these may include any combination of design faults, construction faults, usage, poor maintenance, outside events (such as floods and hurricanes) and simply the unknown. The failure of the Tacoma Narrows Bridge on November 7, 1930, was a result of the properties of wind flow over bluff bodies of the type and shape of the bridge, which were largely unknown at the time of the design and construction of the bridge. The failure of the Hyatt Regency walkway Kansas on July 17, 1981, was a result of the engineer failing to recognize the implications of what appeared to be a minor design change; triggered by a constructability issue with the original design.

When permitted by the client’s scope and available fees and time, an investigation should thoroughly delve into the multitude of issues surrounding the perceived failure.

• Who are the potentially involved parties? This can include the municipality, the owner(s), the members of the design team, other consultants, sub consultants, contractors, subcontractors, testing agencies, material suppliers, and others.   
• What are the potentially involved components and systems? This depends upon the failures and issues which have been identified. For the John Hancock building in Boston completed in 1976, several problems arose. Original completion was scheduled for 1971, which lead to contractual issues.  During construction, temporary retaining walls failed which was a means and methods issue by the contractor. Building sway affected occupant comfort, which was a largely unknown issue of the time. Windows affected by thermal movement and wind forces fell out, largely attributed to design error. In these various failures, differing components were involved. For the individual glass panels, the entire building behavior contributed to the failure.   
• What was the history of the failed component(s), including all non-failed items related to or potentially affecting the failed component(s)? For new construction, acceptance of prior work by ensuing trades often results in failures of later materials due to underlying problems which were not corrected. Historical changes in building layout, loads, materials, and building codes and regulations over the history of a structure become important when considering current issues. For example, a precious metals plant in Nutley, NJ, repeated acid spills and floor repairs led to the presence of a completely unreinforced concrete floor with multiple epoxy and other toppings (the acid had, over time, completely dissolved the reinforcement).

When conducting an investigation, the issue of patterns is very important. This may include patterns of any kind related to the failure. Where there are many, perhaps thousands, of similar items, such as windows, statistical analysis may be justified. A pattern to the failure may be related to physical characteristics such as location, type, or age. A pattern may emerge with regard to the individual or company responsible for the installations. There may also be environmental patterns, such as weather exposure. The existence, as well as the lack of existence of a pattern is very valuable information to the forensic investigator.

Valuable information may be obtained from written documentation. In addition to the basic design documents, maintenance records, correspondence, diaries, inspection records, and other writ documentation can provide insight into the intent, means, methods, changes, etc., of any particular project.

Tools of the investigator may include visual observation, nondestructive testing, destructive testing, sampling, component testing (both in situ and laboratory), full-scale testing, parametric testing, analysis of many different complexities, document review, historical research and other basic research. The actual scope of work will almost always be limited, as both funds and available time are limited. There is; therefore, always an element of uncertainty in the final opinion; however, slight. Hence, most forensic engineering report conclusions commence with the phrase, “The following represents my opinion to a reasonable degree of engineering certainty based upon the foregoing activities.” At the end of the report, a phrase such as, “I reserve the right to amend my report based upon further investigation or information, from whatever source” will also typically be included.

Forensic engineering work often includes delegating responsibility for faults and costs once allegations of fault have been validated. This raises the issue of ethics as, at least in the United States, the client most often is or represents an interested party responsible for payment of the forensic engineer’s fees. Maintaining integrity and independence of opinion can be difficult but is essential to credibility, both written and in sworn testimony, and to professional standards of conduct.

This does not mean that all experts will agree if given the same set of facts.

Example 1: All may agree there is an 8 ounce glass with 4 ounces of liquid. But, the glass may be half full; the glass may be half empty. The glass may have also been poorly designed, leading to wastage of the glass. Or, there may be no fault at all, as the requirement was to provide 4 ounces of liquid into the glass provided.

Example 2: Water penetration through a building façade may require sealants to have failed, but, for the water to cause damage, it may also have had to pass through the façade, water resistant barrier, building wrap, drainage layer and internal finishes and the actual reason water resulted in damage was that the landscaping unrelated to all issues concerning the building façade design and construction, had blocked the exit path for water at the base of the building envelope.

Whatever opinion is developed based upon the available evidence, it must be upon solid technical and scientific grounds. To this end, expert testimony in federal court must be in accordance with the Federal Rules of Evidence Rule 702, Testimony by Expert Witnesses:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

1. the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; 
2. the testimony is based on sufficient facts or data; 
3. the testimony is the product of reliable principles and methods; and 
4. the expert has reliably applied the principles and methods to the facts of the case…

Similar rules apply in other countries.

Lastly, forensic engineers may need to testify as to their opinions under oath. An additional skill, unrelated to the ability of the forensic engineer to investigate and scientifically and impartially determine cause, fault and damages, is the ability to present that opinion in an intelligible and credible manner to an unskilled and largely non-technical audience. Complex concepts need to be discussed in a manner which can be understood by the public. Challenges to the opinion must be successfully answered. Credibility must be preserved. For these reasons, skills in presentation and public speaking are needed, for, without these, the most highly qualified individual with a technically correct conclusion may not be believed.

This article discusses issues of general interest and does not give any specific legal or business advice pertaining to any specific circumstances.  Before acting upon any of its information, you should obtain appropriate advice from a lawyer or other qualified professional.