Digital twins for construction: out with the old, in with the twin

In the case of the architectural and construction sector, the digital twin arrives as an upgrade on its worthy predecessor, BIM. Building information modelling has been around for over a decade and theoretically stays with a building through its concept, design, construction and operation. The problem with BIM, according to Howard Tee, CTO of Newtecnic, is that it is misused both as a term and in its function.

“Stakeholders still misuse the term and say that it’s just a piece of software I need to have on this project,” says Tee. “It’s a fundamental requirement now of government projects in the UK and that’s increasingly the case globally. But it is not one software package, it’s an entire process that informs the entire construction.”

The problem with BIM is that it hasn’t been able to provide the discipline in a project that would be expected of an over-arching framework. Instead, it encourages people to do their own part of a job in isolation and any problems are pushed downstream, potentially emerging as big issues during construction. Tee likens it to a filing cabinet where anyone can put anything in, including unresolved data. He says: “You’ve got people accessing different parts of data within the BIM system which don’t match up – it’s a classic ‘garbage in, garbage out’. Even though BIM is specified on all government projects above a certain value, and in America on all of them – schools, hospitals, the lot – when it actually gets to the work site they discover that although it’s BIM it actually doesn’t work.”

Tee continues: “The term digital twin has started to come in with a view to resolving coordination issues, which is the promise that BIM has put forward for many years but hasn’t really ever delivered upon. The point of having a digital twin is to have resolved all those issues much earlier than would have been done in traditional construction. In our case, it means the kit of components that make up a building can be fully understood, resolved, and then you’re simply building it like you would an Airfix kit.”

Specifications, therefore, become specific. Rather than saying “there will be a door here” and leave it to someone down the line to resolve, the exact dimensions of the door are created along with its materials, even construction methodology. It means everyone is using exactly the same data set during design, construction and, ultimately, operation of the building. The digital twin effectively becomes a user manual.

What’s more is that this 3D environment can add a fourth dimension – time – and this can impact on the actual process of constructing the building. A key consideration here is that the 3D model is not just a CAD geometry model; it is a performance model with an inherent understanding of the capabilities of all the materials and the stresses and strains as they all interact. With beefed-up computing power now available to all, constant simulations are possible that can then provide information about structural integrity during the building process.

“It allows us at the early stages of a project to be able to put forward a proposal for how you build that building in a sequence – that’s part of what the digital twin is wanting to deliver upon,” claims Tee. “Adding in performance and time... the earlier you can do that in the design process, absolutely the better it can be. You’re more likely to get buy-in from everyone involved because you’re de-risking as you go by having that level of certainty.”  

The result is a brick by brick, component by component guide demonstrating how to assemble everything and in exactly what order. Such are the capabilities of the computer hardware and analysis software that iterations and simulations can be done at great speed, running alongside and informing the construction process and adapting to it.

It goes further than just the building under construction. It covers efficient operation of the building site – how to store things, what will be the effect of bad weather, what lifting equipment is needed and what will be their optimal position, even looking at whether it is worth building sub-assemblies and other pre-fabrication on site rather than transporting them in.

Of the many advantages that presents, the most compelling is that the time taken for the design and construction phases can be reduced considerably. Employing building contractors for weeks rather than months can make a big difference to project viability.

‘In some cases you have to partly reassemble a building, that’s a critical part of a digital twin for a big construction project’

Once in use, modern buildings often deploy a building management system (BMS), the tool that regulates maintenance and operation (heating, ventilation, lighting, security, room use etc) of that building. Unlike BIM, BMS has gained widespread acceptance as a productive management tool. However, even this has its limitations. Jeff Casey, business development director for Burns & McDonnell in the UK, says: “Traditionally buildings have been considered as static assets – once they are built the only work left is routine maintenance over the useful life. Building owners, especially those in manufacturing and heavy industrial processes, are appreciating that assets are dynamic things that need closer monitoring and control after construction.”

Tying building design and process design together into a ubiquitous model – the digital twin – enables the end facility owners and managers to make investment decisions from actionable data. This helps clients to make decisions more efficiently, understand impacts of changes, enhance asset use, and ultimately manage assets over time.

It will also provide the foundation for new methods of working – the main picture shows a futuristic look of cobots and humans performing standard maintenance on the Newtecnic design-engineered façade of The King Abdullah Financial District Metro Hub in Riyadh, Saudi Arabia. The digital twin here could provide the link between incoming information, from both simulation and real-time sensor feeds, and scheduling of automatic and reactive maintenance operations.

Casey continues: “More and more assets have sensors and comms, meaning that they are able to generate data on their current condition – both from a health and operational standpoint. This is naturally enabling the transition to a digital twin, but we are still in the early days. Better system integration in space, optimising under­performing assets and process in near real-time, are all benefits; as is the ability to quickly identify and locate assets in poor condition in the system to prevent outage or catastrophic failure.”

Andrew Watts, CEO of Newtecnic, adds: “Buildings are around for a long time. A car needs to be there for 10 years, but a building needs to be there for 100-plus years. So, the interaction is between a finished item and how it weathers, how it’s maintained and looked after, and how it’s assembled. Because in some cases you have to partly reassemble a building, that’s a critical part of a digital twin for a big construction project.”

Many buildings have to be reconfigured, re-clad or changed in other ways, and having the digital twin as a performance-based model, rather than just geometry, allows users to predict how the changes will affect the condition and operation of their buildings.  

Casey concludes: “Transitioning or adapting from the BIM model to a digital twin is where the real value comes from, ensuring that real-time data through sensors is incorporated into the model to create the real-world simulation.”