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Success and the single model

Project collaboration

Many jobs use project collaboration tools but none have worked in a total single model environment - until now. Alan Sparks looks at how Heathrow Terminal 5 has grasped the nettle.

For a commercial operator such as BAA to tackle a project like Heathrow Airport's £2.5bn Terminal 5 (T5) with a bulletbiting approach, there must be big savings to be made.

And there are. 'By using a single model environment we believe that savings of up to 30% are possible, ' says Laing Construction CAD technologies manager Mervyn Richards on the benefits of cutting out waste through comprehensive design.

T5 will be built using full 3D models that can be used by each chain of the construction team, from architects, structural engineers, and mechanical and electrical engineers, right through to cladding and fit-out specialists.

Technology to cope with a scheme as large and wide-ranging as T5 has existed for some time. 'But the main challenge is cultural, convincing our partners that this is the way they have to work, ' says Richards.

The model will centre around AutoCAD 2000. Then using CSC 3D Plus, which allows analytical design input into 3D models, a common model can be produced. Further packages then perform other specialist tasks. CAD-Duct, for example, is used to drive plasm a machines to cut pipework direct from the 3D model.

Other commonly used packages such as X-Steel and StruCAD can also operate, ensuring accurate designs from subcontractors working further down the supply chain who otherwise risk working from outdated architect's drawings.

'This ambiguity inherent in traditional construction practice is responsible for around 10% of waste alone, ' adds Richards.

The reduced need for production drawings, which typically accounts for 60% of the design fee, is also an opportunity for savings. 'Much of this can be eliminated by using a common 3D model, ' explains Richards.

As only checking and approval require hard copies, fewer 2D drawings will be needed.

Investment in training is critical and is still seen as a stumbling block for many in the industry, a myth that Richards is keen to dispel: 'On this scheme, training only amounts to 1% of total cost. We tell our partners that if you do not want to make the investment, then the industry does not move forward. Simple.'

As client, BAA knew what it wanted. And in order to beckon the industry forward along with its own vision, it undertook widespread training throughout the construction chain.

'Over the past six years we have analysed building projects.

Areas where waste is created and where savings can be made have been identified and this has helped us target just where we can make up the most ground, ' says Richards.

Extensive collaboration during the Heathrow Express project took place using 2D.

This level of sharing data led to successful design and gave BAA the thirst for more. A £6M office block development built in 1998 was conventionally constructed but with greater cost and material monitoring. Subsequently, it was found that an immediate 10% saving was possible by cutting out waste solely due to ambiguity.

The architects and M&E engineers were not using the same dimensions. Data streams were also badly managed, explains Richards.

'Each construction stage was unaware of just what stage of the iterative design process each was at, assuming one element was written in stone when it was only written in sand, ' he says.

This evidence convinced BAA that investment in revolutionising design practice would be prudent. And this is not a selfish investment, as the training undertaken will be to the benefit of all involved, says Richards. 'As a result of T5, between 40 and 60 companies will have the skills to take the lessons learnt here forward across the industry.'

For T5, which is predominantly a steel structure, the technology and economic benefits are apparent. But concrete design needs more nib and aperture details which demand a greater level of precision, says Richards, meaning that potential gains will not be as great as steel. 'Concrete might be harder to crack.'

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