Many claims against structural engineers arises as a result of a perceived defects in the services they have provided. For most structural engineers, this idea is anathema, but it remains the most basic cause of claims instituted against them. For every professional making a recommendation based on the knowledge they have on a subject, there exist another person prepared to rely on it. This is even more true for the construction world, where the result of any wrong recommendation/advice would be litigation instituted against the affected party.
Perhaps, the perils of having an opinion in architecture, engineering and construction is that all your opinions and recommendations are treated as notorious facts, even when they could be wrong. This article seeks to establish the link between design defects and issues of competency.
In 2018, this writer was on a project, the architectural design brief called for a four-storey building excluding the basement level. The building was mixed use, housing classrooms, halls, offices and residential apartments. The building had moderately stringent architectural requirement due to a constraint to have only one row of concrete columns in the large halls, hence long spanning concrete slabs were required. The client a chief structural engineer himself, had out-sourced the structural design due to his tight schedules and the timeline required to carry out the design.
A civil engineering consultant was then brought in and instructed to undertake the design. A scheme was prepared and delivered to the client who gave no indication that he wasn’t satisfied with it. The structural design scheme called for a reinforced concrete solid slab construction with columns and beams spaced on a grid of (7.5m & 9m) in both directions. Having approved the scheme design, a detailed design was prepared and sent for approval and a contractor was appointed to carry out the implementation.
During implementation, the site engineer noticed some of the columns in the same design group (i.e., columns resisting roughly equivalent loads) sized differently. Some were (450mm x 450mm) while others were (400mm x 400mm). The site engineer then raises this concern with the consultant who promised to check and clarify the issue. Under some pressure from the contractor to the site engineer and then to the consultant, the consultant approved the (400mm x 400mm) thick columns, reasons being that the scheme design submitted earlier assumed the same column sizes. Hence the site engineer proceeded with (400mm x 400mm) concrete columns.
However, during preparation for the concrete pouring of the third floor, the client would request a check for the possibility of the entire roof being decked for recreational and storage purposes. This check revealed that these concrete columns were not even adequate to support the third floor save the additional roof deck. Apparently, the consultant did not carry out the design himself but also outsourced the design to another engineer who simply used a software package to generate calculations and drawings for implementation.
Expert’s evidence criticized the consultant approval of (400mm x 400mm) columns stressing that a simple tributary area calculation would’ve revealed the inadequacy of the design, and this should’ve been obvious to any competent structural engineer. More interesting, was the fact that, at first floor level, one of the main concrete beams with a span of 11.25m had cracks at the supports as soon as the temporary supports were removed indicating a shear failure.
To sum it up, there were was a deficient structural design. The critical problem here, has little to do with a lack of ‘duty of care’ neither is it the tendency to give advice under pressure. It has to do with the competency of the appointed consultant. Evidence available suggests that the consultant was a geotechnical specialist and hasn’t consulted in any area of structural engineering. But because the engineering regulatory body grants him a seal that gives him access to vet all civil engineering designs he accepted this appointment, what was then lacking was the adequate experience, ability and knowledge of structural engineering principles enough to recognize, point out errors and correct them.
As a result of this design error, the decision was made to retrofit the entire structure as soon as the third-floor concreting was done. This saw an increase in the central column size and the introduction of concrete beams to break up the wide slab panels from (9m x 7.5m) span to (9m x 3.75m), creating the very design defect that was brawled at during the conceptual design stage.
Ethics & Competency
Many structural engineers will recognize the words, reasonable, skill, care and diligence to be expected of a qualified and competent structural engineer. But what do these words actually mean?
BS 5975 defines a competent person as ‘someone with sufficient knowledge of the tasks to be undertaken, the risks which the work to be done entails and the with sufficient experience and ability to enable them to carry out their duties in relation to the project, to recognize their limitations, and to take appropriate action in order to prevent harm to those carrying out construction work, or those affected by the work’.
This definition would seem to provide the best means for structural engineers to assess whether they are competent to undertake a specific task. While being Registered is a recognition of a degree of competency which Continuing Professional Development (CPD) helps to maintain, this in itself is not sufficient to truly assess competency as defined above.
The importance of ethics is becoming increasingly important within almost every profession. Competency is fundamental to ethical behaviour. Competency requires that members of a profession only tasks for which they’re competent in.
As structural engineers we must always be honest about our limitations. Sometimes we may have more knowledge and experience but perhaps our design abilities have diminished with time either due to the introduction of new codes and software’s or for whatever reasons. When confronted with a problem, we must recognize our limitations and seek help from those who have competency in those areas wherein we might lack the necessary knowledge, experience and abilities. For example, you’re very competent in the design of steel and concrete structures but you’ve being tasked with designing in structural glass, you must recognize your limitation and engage the service of a competent personnel.
Aspects of geotechnical engineering and design, also easily come to mind as areas of expertise for which a structural engineer might be found lacking in knowledge. In larger organizations, this is often not a problem due to the presence and wide array of abilities and experience that exist. However, for smaller practices comes the problem of even convincing a client that others need to be appointed to undertake jobs due to a partial lack of experience of the appointed engineer. Whatever the case, a conversation should always be held with the client at the appointment stage rather than halfway through the design process, unless of course variations to the appointment are introduced or unforeseen circumstances arise.
Recognizing your own limitations and those of your team is not a sign of weakness but rather strength, and taking appropriate actions is a fundamental requirement for both competency and professional practice
In summary, here are four questions a structural engineers must provide honest answers to, when undertaking a task or leading a team to undertake many tasks in a project:
- Do I have the experience to undertake this work?
- Do I have the knowledge and abilities required to undertake this work?
- Where are my lacking in experience, knowledge and abilities; can I overcome the shortfalls?
- How do I find information and those with knowledge, experience and abilities in order to achieve competency in these tasks?
Sources & Citation
- British Standards Institution (2008) BS 5975:2008+A1:2011 Code of practice for temporary works procedures and the permissible stress design of falsework, London: BSI
- Institution of Structural Engineers (2018) Business Practice Notes 15: Competency [Online] Available at: www.istructe.org/ (Accessed: March 2022)
- Institution of Structural Engineers (2022) Code of Conduct and Guidance Notes [Online] Available at: www.istructe.org/ f(Accessed: March 2022)