To celebrate 50 years of Oasys, Peter Debney reflects on innovation and structural engineering development.
Structural engineering tools have transformed how quickly we model, analyse, and collaborate, expanding possibilities across design. Yet the core responsibility remains the same: understanding structural behaviour and applying sound engineering judgement. As workflows become more digital and interconnected, engineers must continue to question, verify, and communicate their designs with care.
From his early days as a senior structural engineer, through his experience as a professor, author, and IStructE fellow, to his current position leading global Oasys customer service and onboarding, Peter’s career offers a unique perspective on how the profession, and its tools, have evolved.
Image credit: Liz Dunford
Can you summarise your 25-year journey at Arup in one lesson about engineering judgement?
“Technology is a wonderful accelerator and facilitator to our work, but engineering judgement remains the keystone. Without it, things fall down. Despite all the hype, while their daily tasks and processes may change, the human remains at the core of engineering design.”
Was there a project or moment where you felt the profession “crossed a threshold” into a new digital era?
“I think that there have been several thresholds over the years. The first, and perhaps therefore the most significant, was in about 1960 when Arup started the first significant use of Finite Element Analysis (FEA) on the Sydney Opera House (SOH), as well as taking the first steps in parametric design (on the SOH glass walls).
Since my career started, I have seen the widespread introduction of Computer Aided Drawing (CAD) in the late 80s/early 90s to replace the drawing boards, Building Information Modelling (BIM) in the mid/late 90s, and parametric modelling (also in the 90s). It did take several years for all these aspects to ‘bed in’ and be widely accepted in the industry.
While we have been talking about AI in construction for a decade or more, it is only in the last few years that serious interest and exploration of application has been seen in the general profession; I am looking forward to seeing what impact it will have on design and construction.”
What’s something you’re proud of from your time supporting engineers globally?
“I have been fascinated by the Sagrada Família basilica in Barcelona for decades and it was a great privilege to support the Arup engineers using Oasys GSA on the project. They were modelling the thrust lines of post-tensioned masonry used on the towers and façade, which conventional wisdom says cannot be done. Yet, they did it. It shows what a versatile tool GSA is in the hands of expert engineers.”
What did we gain and risk when engineering went digital?
“Engineering requires a lot of calculations, from figuring out the forces and moments on a structure, to determining what sections or reinforcement is needed to make the structure both safe and economic. Computers are mathematical machines, that can not only perform calculations perfectly, but also considerably faster than we could ever dream of doing.
In addition, FEA programs, such as GSA, are general purpose algorithms that can analyse a huge range of structural types. This means that you do not need particular formulas for particular structural forms.
With hand calculations, you must understand the structural behaviour before you start otherwise you do not know which formulas to use. Because this knowledge is not essential to running digital calculations, there is the risk that young engineers forget that the understanding is essential for them to validate and verify their model and its outputs.”
What do you think a modern structural engineer must understand about numerical methods to use software responsibly?
“The first crucial thing that engineers must understand about numerical methods is their particular limitations: what the programs do not do. Then they can judge whether the program is valid for addressing their design requirement. They might do this by understanding the underlying mathematics or by understanding the principles (quantitative or qualitative, if you like). For example: if the displacements or stresses are large then you need a nonlinear analysis, or a buckling analysis if compression is significant.
You also need to ensure that your model is valid for the analysis. Static analyses may need element releases to be included while dynamic analyses can require them to be excluded. Nonlinear analyses will include material nonlinearity if you specify nonlinear materials. Support stiffnesses might have a significant impact on the results. And so on: the list is large and the engineer needs to be aware of what their analysis question and method needs of them.”
When you look ahead to the next 50 years, what changes do you expect and hope for in everyday structural workflows?
“Looking back over the last 50 years, when structural engineering computer usage was minimal and expensive, programmed by punched cards, few graphical outputs, no internet and no mobile devices, to today, I can confidently predict that the changes over the next fifty years will be much more. The rate of technological change is accelerating, so change is the new normal.
It is also good to remember that structural engineering is naturally conservative: people’s lives depend on what we design, so safety is our top priority. We also recognise that lives and wellbeing depend on us putting the brakes on climate change, and the construction industry is a major contributor to CO2 emissions.”