(STRUCTURAL) COMPUTATIONAL ENGINEERS

Dit artikel verscheen in KOersief 113 - juli 2021, het magazine van studievereniging KOers, de studievereniging voor Constructief Ontwerpers aan de TU/e.

Door: Eren Duru - Structural engineer at BouwQ

Structural engineers are a critical link in the process of building. They facilitate the realisation of safe, durable and economically justifiable buildings and other structures. Structural engineers are typically involved in every phase of the building process. They therefore require a very wide technical knowledge and the skills to apply this knowledge. This is not only important when designing new structures, but also - and possibly more so - when coming up with additional measures for dealing with execution errors, or when designing changes to an existing building. Answering third party questions before, during and after a building process is customary to a structural engineer. Knowledge and skill are, after all, the engineers trade.

Being an inspection firm, we are involved in design reviews as well as inspections on the execution of building projects. During our operations we find that more and more errors can be linked to unskilled use of calculation software. While the digital revolution in our trade creates opportunities to design more attractive and complex structures, our reviews are also showing the perils and pitfalls of current and future automation, and the hazards they may pose to the integrity of building structures.

“Time is money! Structural design needs to be faster and more efficient.” This sums up the motivation of many engineering firms, who are focussing on automation to obtain this goal. While it is completely logical in today’s economy, this motto would have been laughable forty years ago. Back then labour was cheap and building materials were costly. There was no calculation software, so without specialist knowledge it was impossible to make structural calculations. Mechanics schemes were calculated by hand. The more complex the calculation, the more knowledge and experience was required. With the rise of calculation software, enveloping both mechanics and building codes, the trade has gradually evolved. The early software was great for quickly producing a presentable calculation, which would have taken a lot of time without a computer. One could input an entire steel truss for instance, and get a clear overview of its response to loads. Because the level of automation was fairly low at this time, the experienced engineer running this computer model could easily see whether the output made sense or not.

Currently many companies are investing large sums into the automation of their engineering processes. They are also developing their own tools, to run alongside the more established and widespread calculation software already available. This is fine, as long the people using these tools are aware of their inner workings, or there is an experienced structural engineer at the end of this design process, as a checksum. Unfortunately as an inspection firm we come across errors in calculations by engineers and suppliers on a daily basis. We find that users assume the output of their software tools as gospel, regardless of their own input. This is especially the case with complex calculations, often utilizing FEM software or extensive spreadsheets, where the individual steps of a calculation are no longer evident to the user. The calculations being performed inside such a software tool can be seen as a black- box, introducing a new group of engineers: The button pushers. They forget that software can only do what you ask it to do. It’s incapable of thinking about the correctness of your input or how that’s supposed to relate to its output. The human factor continues to play a vital role in this.

It should be obvious that experienced engineers will remain indispensable to the design process in order to yield structures of which the safety can be guaranteed. When dealing with complex structures the involvement of an experienced structural engineer is of vital importance. She or he can use their experience to judge manufacturability and the plausibility of a calculations results. However, it is not just complex structures and homebrewed software in which user errors occur. We are seeing an increasing number of cases where basic structures are wrongly input into common framework software. This must be because engineers are unaware of their own inability to schematise correctly, which is called unconscious ineptitude.

A current trend is software that can link structural calculations directly to a BIM model, virtually without user interference. This is an especially potent application, offering many interesting possibilities. This type of far-reaching automation will however lead to increasingly fewer opportunities for new graduates to be involved in schematising structures and doing calculations by hand. This threatens to erode professional knowledge (including the relationship between mechanics and detailing), possibly eliminating the (traditional) structural engineer in the future.

Logically, incompetent use of calculation software will lead to errors. To prevent these errors, continuing presence, involvement and alertness of experienced engineers is of vital importance. Unfortunately, this isn’t always the case in practice. This will in fact, in light of the revolution in calculation software, be the case more and more often. For this reason, or to safeguard the safety and quality of buildings and infrastructural works, BouwQ is enlisted as an independent technical quality assurance firm. By performing targeted checks in all phases and on all aspects of buildings and building processes, BouwQ can guarantee quality and safety. It is our task to reduce errors in building practice and to lift build quality and safety to a higher level. Obviously this requires expertise. We have the knowledge, experience and processes to prevent errors from creeping their way into structures. Our first thoughts are for risks, schematisation, cooperation between a structures parts and the detailing this requires. We make approximating calculations by hand, to reveal whether a designers computer analyses makes sense or not. Furthermore, we train young engineers to schematise thoughtfully, to make quick approximations to compare their complex computer models to and to always, ALWAYS keep thinking for themselves.

“Why do we study complicated sums, while companies use calculation software to do this?” If you’ve been on an internship, you may well have wondered about this. Don’t worry, knowledge of the craft will certainly remain necessary to fulfil a profession as a structural engineer. However, reshaping the curriculum may prove necessary to bridge the gap between study and practice. Technical education will need to prepare students for a lifetime of collaboration with computers. For instance by adding a course specifically targeted to automation, where you might learn to set up a (basic) spreadsheet. In the future structural engineers will need to be better able to understand what goes on inside software and to appreciate the importance of what they feed it.

Automation is a beautiful thing that provides the possibility to achieve even more beautiful structures (which may have been impossible to design in the past). One day it might even be possible to have computers and robots that design and build entire buildings, without us ever lifting a finger. But we do need to realise that enough checkpoints have to be built-in. Verification and validation steps, executed by substantively competent structural engineers who watch over the safety of the entire building and push on the automation-brake in time to prevent errors in design and execution. Imagine working at a company that does just that.

Werken bij een bouwinspectiebureau kan heel veelzijdig zijn, waarbij je zowel op locatie als op kantoor werkt. Wil je meer weten over BouwQ of solliciteren? Kijk dan op www.bouwq.nl/students.