Building Information Modelling can promote cooperation through the supply chain.
More from: BIM: Change culture
The traditional process of bringing materials to site and combining them there into their final form is gradually giving way to offsite manufacture and installation of ready-assembled components.
Consequently we’re seeing the construction process become increasingly industrialised, with an increasing proportion of “construction” work being done under factory conditions.
Building Information Modelling (BIM) is at the heart of this process. Linking 3D design models with highly efficient, often robotic production techniques enables off-site assembly in a way that’s never previously been possible.
We are now able to plan how and when larger pre-fabricated elements are incorporated into the works by using 4D BIM - 3D design plus scheduling - for construction planning.
The move to “component based design” profoundly affects materials, product and performance specifications - and who’s responsible for what.
Over the decades, responsibility for selection of components has increasingly fallen to the contractor, based on performance requirements drawn up by the design team. This tendency has been driven by the belief that the contractor has the greatest buying power, and best understands the practical issues, so can deliver best value to the client.
However, some architects and consulting engineers object that this is at the cost of design quality and question the real value delivered to the client. Spatial and schematic co-ordination can be adversely affected by late decisions on plant and equipment. Alternative options do not always deliver the required performance. And only part of the savings achieved by the contractor’s best-buy purchasing are passed on.
BIM will play an important role in getting around this cost versus quality and performance debate. BIM working processes involve greater collaboration between client, consultants, the contractor and often first tier suppliers and subcontractors.
Greater effort is put into developing design detail in order to optimise the project both for construction and operational performance.
It seems likely that commercial pressure to get the full benefit from the “virtual build” capability offered by BIM will lead to an earlier resolution of component selection - so that everybody involved in the project knows what to expect.
As part of this move we’re starting to see manufacturers create online object catalogues which store information about each product. These BIM object catalogues can contain a 3D model of each product within which is embedded information on dimensions, materials and operating capacity, cost, embodied carbon, operational energy demand and associated carbon emissions. They can also contain guidance on commissioning, operational and maintenance procedures, and information on how to order and fit replacement parts. Model-based access to relevant information will enable project partners to specify and procure correctly when owners are making the initial investment and then to get the best performance over the life of the asset.
Such changes look set to bring real benefits to the clients. The underlying tension between consultant and contractor over design and product selection will not go away, but BIM should be able to convert it into constructive dialogue through well-informed collaboration.
- Richard Shennan is a Mott MacDonald director with responsibility for implementing BIM across the company worldwide
BIM can get better results