Computer-aided design has revolutionised the building and construction industry. At first, CAD was simply an electronic facsimile of architectural drawing, but technological developments such as 3D wireframes and “solid modelling” have pushed the capabilities of CAD software beyond what was possible with draftsmanship.
As processors became more powerful and storage cheaper, the amount of information that architects and engineers could build into their CAD models grew. In the 1990s, CAD software makers began to offer the ability to add ‘parametric’ data such as the characteristics and cost of particular building materials.
This has progressed to the extent that the most sophisticated CAD software today allows the user to model anything from the carbon footprint of a design to the way in which a structure will bend in the wind.
This is known as “building information modelling”, or BIM, and for a number of years now it has been the talk of the construction industry.
BIM is a little like customer relationship management (CRM), in that it refers both to a business practice and a category of software. It is defined by David Philp, head of BIM at construction company Mace Group and an advisor to the UK government, as “constructing a managed digital information 3D model of an asset, be it a building or an infrastructure project that is infused with data”.
BIM’s proponents argue that it offers a range of benefits. The most immediate is improved productivity of construction projects, says Dominic Thasarathar, construction industry programme manager at CAD market share leader AutoDesk.
“The construction industry has historically been pretty poor on productivity,” he says. “There’s an oft-cited statistic that up to 50% of building projects going over time or over budget.”“BIM offers greater efficiency in deploying men, machines and materials,” Thasarathar explains. “You can work out how to schedule the project, and you can get better insight into cash flow over the lifecycle of the project.”
Construction projects typically include a large number of organisations, and BIM also promises to improve collaboration.
According to Huw Roberts, marketing VP at construction software vendor Bentley Systems, the company’s BIM products are being used to co-ordinate Crossrail, Europe’s largest construction project. “Crossrail is a really a bunch of different projects,” he says. “There are station projects, tunnel projects, and more besides.
“The control of the information about those projects is all being done in our ProjectWise software,” he says. “It has a federated data model, so each project is modeled individually, but the models can be integrated so you can open them up as a whole and see how they fit together.
”Another benefit of BIM, Roberts says, is that it allows architects to build more sophisticated models of their designs, and therefore find novel solutions to architectural challenges. “Architecture firms like Fosters, Morphisis and Zaha Waheed are using BIM to explore shapes, structural systems and assemblies of materials that they wouldn’t otherwise be able to understand and simulate,” he says.
One example is the Park House development, a £100 million project to convert build a mixed retail, office space and residential site in London’s Mayfair. “They’ve maximised the amount of space that they can get on the site without impacting the neighbourhood by giving the building a very subtle but complex curved form,” explains Roberts.
Yet another application of BIM occurs after construction is complete, and the CAD files are handed to the building operators as documentation for the site. In fact, AutoDesk’s Thasarathar reports that handing over BIM?files is an increasingly common contractual obligation.
The use of BIM in the construction industry has rocketed in recent years. According to an annual survey by the Royal Institute of British Architects, only 13% of architects and structural engineers were using BIM in 2010. That figure shot up to 31% in 2011 (it rose more modestly to 39% in 2012).
In the latest survey, however, respondents were not unanimous about the benefits of BIM. Only 46% of BIM users agreed with the statement that “adopting BIM increases profitability” and only 55% agreed that “BIM brings cost efficiencies”.
Still, adoption looks certain to grow: 93% of all respondents said they that expect to be using BIM in five years.Architects and engineers are evidently coming under pressure from clients to adopt the practice. Just under three quarters (73%) of BIM users, and 49% of non-users, agreed that “clients will increasingly insist on us adopting BIM”.
One major client that will soon insist on BIM is the UK government. In its construction strategy, published in May 2011, it announced that all public sector construction contracts will be procured using BIM by 2016. This, it says, will help it to cut construction costs by 20%.
There are four “pathfinder” construction projects using BIM underway, including the Ministry of Justice’s redevelopment of Cookham Wood Prison in Kent. That project saw the MoJ become one of the first buying organisations in Europe to issue the BIM Employer’s Information Requirements with the contract tender, specifying what data it would need from the successful bidder and in what format.
The government has decided that it wants its building contractors to present BIM data in the Construction Operations Building Information Exchange (COBie) standard, which was developed by the US Army Corps of Engineers.
COBie is not so much a file format as a spreadsheet design that offers a pre-determined structure for non-graphical building data such as the carbon footprint of a given project or details of the contract.
Another BIM standard is called IFC, which is an open document format operated by an organisation called buildingSMART. In the BIM maturity model, use of the IFC format is considered an indicator of “Level 3” BIM, the highest level, as it allows “fully open data and process integration”.Interoperabilty is an important consideration in BIM.
Not only do most construction projects involve a number of different contributors, who may all be using different software, BIM documenta need to last as long as the building, without becoming obsolete.
Both AutoDesk and Bentley say they are supporters of open standards and interoperability, although Bentley’s Roberts says that not all the functionality of its software can be squeezed into these standards. “Anything that is designed to be a common denominator is going to be less complete than the innovation that is in our system, or in our competitors’ systems for that matter
.”In future, the addition of more and more data to building design software promises to bring some interesting analytical capabilities to the construction industry. Bentley, for example, is working on what it calls “multi-disciplinary optimisation”.
This, Roberts explains, is a utility computing service that will allow customers to define the requirements and aims of a project, and automatically simulate thousands of possible designs.
“Analysing just one of these options might take you 18 hours on your local computer,” he says. “But using cloud computing and massively parallel processing, we will be able to run thousands of simulations in a few hours.”
This may well lead to new and unusual building designs, providing yet another example of how data analytics is reshaping our environment.