Building information modelling (BIM) is a process for creating and managing information on a construction project through the entire lifecycle.
Tony King, BIM systems co-ordinator in Mott MacDonald’s power transmission and distribution division, is on a mission to push the benefits of the technology throughout the group, particularly in infrastructure and utilities. “BIM is something we should be doing as part of standard delivery, rather than being held up as an innovation,” he says.
Tony recently completed an MSc in BIM at Salford University. Here, he answers some questions about BIM.
What is the excitement over BIM?
BIM was central to the UK government construction strategy, which was published in 2011 and outlined a four-year programme to modernise the construction sector, and reduce the capital cost and carbon burden of the built environment by 20%. It set the foundation for the BIM revolution to take off.
The government set up the BIM Task Group, which has driven the standards and requirements to enable adoption of the technology. It also established the principle that future government-funded contracts should be BIM compliant.
How do you describe BIM?
BIM is simply a digital representation of the physical and functional characteristics of an asset. It is an integrated process that provides co-ordinated and reliable information on all phases of a project – from concept, through to detailed design, construction and operation. The goal is to construct things that are better, cleaner and cheaper, and to do so quickly and with minimal risk.
How does BIM lead to efficiencies?
The benefits vary greatly depending on where someone is involved in the process. From a design perspective, a BIM model brings together a huge amount of work from different stakeholders. Designers get an amalgamation of information from various sources and teams, all pulled together into the same place. They enjoy unprecedented sharing of information, helping them knock out any kinks in the design and construction phases virtually before building work starts.
BIM also helps avoid data atrophy: if someone completes a concept design and then passes it on to another party for the next phase of design, there is a risk that the new designer will opt to start again from scratch, repeating work that has already been done. With BIM, the digital model will include space holders for every element, together with the appropriate level of associated information. The space holder objects can then be swapped for more defined elements, both in terms of geometry and information, so that when a project moves from concept to detail design the focus is on refinement rather than beginning again.
Other benefits include the ability to interrogate the model and do additional modelling. In the case of an electrical substation, for example, interrogation of the design might include checking electrical clearances. The model allows you to see where there may be issues.
You’re working on a catalogue of objects. What is that?
Underpinning BIM at Mott MacDonald is a searchable, central database or catalogue of standardised components. Once fully implemented, this will enable designers to easily source components with consistent levels of information attached. It is a rationalisation of a process that occurs already.
The first question when a new project commences is invariably: Have we done this before? Followed by: What did we do? Integrating the catalogue of objects into the BIM design process formalises that process, leading to greater efficiencies in time and cost to pass back to the client.
It is a unified approach across Mott MacDonald departments and the company is pushing it in transmission in a big way. Once everyone is on board, we’re going to end up with a very powerful catalogue of components at our disposal across a variety of sectors.
We’ll have immediate access to the information we must attach to an object. The objects carry data with them and this can be tracked through the model. During construction, operation and at later stages in the life of an asset, information can be extracted, providing owners with a much better understanding of the design and how best to operate the asset.
You mentioned that people tend to get a bit lost in the model. Elaborate?
It is easy to miss the detail when looking at the striking graphics. It’s important to use the model appropriately; a quick glance does not necessarily convey that the design has been engineered to the correct specification. The focus should always be on the engineering, not the pretty pictures you can export from it.
The power of BIM is the information in the model and attached to objects – where they are in the world, how they behave, their relationship to other objects. That is the real advance. The client receiving a model is receiving a huge amount of information relating to their asset. Harnessing the data is as important for the client as it is for the designers and contractors.
So the fancy rendering to create the graphics is essentially an add on?
Ultimately, what we deliver is traditional 2D drawings broken out of the 3D model. It must be in a format people understand and site staff will still refer to a 2D technical drawing.
BIM was introduced as a way of achieving efficiencies, are those being realised at the rate hoped for?
It’s very hard to get metrics on the savings. People frequently talk about achieving a 30% reduction across the project lifecycle, from concept to as built, but it is difficult to pull the numbers together. The challenge, particularly in an area like power transmission and distribution, is the project scope is different every time. That makes it hard to get a good comparison between the costs of a BIM project and a traditional design.
However, it is true that, because we are seeing much greater context and can interrogate the design to a greater level, we are identifying more errors than previously. The upside of this is a more robust design and we sort problems out earlier and can eliminate issues in construction and cost.