What is BIM?
There is no universal definition of BIM and definitions continue to evolve. However BIM is not software. It is much more than 3D-modelling. It is a business process, and therefore you cannot go out and “buy BIM”.
- BIM is both technology and a new way of working, i.e. tools which improve delivery of outputs, and implementation of a collaborative culture.
- BIM is about information, communication and delivery, with greater emphasis on “information”.
- BIM is a digital representation of the physical and functional characteristics of a facility in order to work out problems, and simulate and analyse the potential impacts.
- BIM is a shared knowledge resource, forming a reliable basis for decisions during a facility’s lifecycle.
5D BIM can be defined in terms of the multi-dimensional functions:
- 3D – parametric design models and space programming tools, i.e. use of spatial dimensions of width, length and depth to represent an object, which enables 3D visualisations and walkthroughs, clash detection and coordination, and item scheduling.
- 4D – this is 3D plus “time”. The ability to link the individual 3D parts or assemblies with the project delivery timeline, including scheduling of resources and quantities, and modular prefabrication to assist tracking and project phasing. In addition to collaboration, 4D simulations function as communication tools to reveal potential bottlenecks. Both planners and contractors can use BIM onsite for verification, guidance and tracking of construction activities.
- 5D – this is 4D plus “cost”. Integration of design with estimating, scheduling and costing, including generation of Bills of Quantities, and derivation of productivity rates and labour costs.
For project managers, planners and quantity surveyors, integrated 5D BIM will enable them to:
- Offer clients the chance to explore several different scenarios, i.e. illustrating how a change in design impacts both the programme and budget. Cost estimates can be linked to the BIM model so that a change in the design would be immediately reflected in the budget and programme. As part of Integrated Project Delivery, it is possible to work on a “live model”, meaning that a change in the geometry of the facility (3D model) will change the calculations for the programme and cost.
- Provide the project teams with resource-loaded schedules, accurate cash flow forecasts, detailed project risk analyses, and even resource forecasts for major subcontractors.
The Benefits of BIM
- Enhanced information exchange and added document control, including sharing models, meeting minutes, project images etc.
- BIM aids design of sustainable facilities. Environmental Performance Modelling entails analytical and simulation technologies. Simulations can be used to find the ideal building orientation, and to calculate the potential return in energy and the feasibility of each system, until performance is optimised.
- Interoperability, i.e. the ability to share data across applications.
- Elimination of unbudgeted changes on projects.
- Cost estimation accuracy to within 3%.
- Up to 80% reduction in time taken to generate a cost estimate.
- Clash detections, particularly services, providing time and cost savings.
- Reduction in project delivery time.
- Reduction in remedial works due to enhanced quality control and design coordination.
- Built-in structural analysis capabilities, which are key for fabricators.
Making BIM work
- An organisation must first determine its business processes, then buy the software that will support those business processes, and not the other way round.
- At project level, there should be a willingness to share information and work collaboratively, i.e. integrate design with construction.
The UK Government’s Position
The UK government recently announced that public projects will now be expected to employ BIM processes.
Paul Morell, the government's chief construction adviser said, "Within five years, all government procurement will be within 3D collaborative BIM, with specific exceptions where the cost might exceed the benefit, although I have to say I am struggling to think of obvious examples of that".
Business must meet the following by 2016
Level 2 BIM
This is distinguished by collaborative working – all parties use their own 3D CAD models, but not necessarily working on a single, shared model. The collaboration comes in the form of how the information is exchanged between different parties – and is the crucial aspect of this level. Design information is shared through a common file format, which enables any organisation to be able to combine that data with their own in order to make a federated BIM model, and to carry out interrogative checks on it. Hence any CAD software that each party used must be capable of exporting to one of the common file formats such as IFC (Industry Foundation Class) or COBie (Construction Operations Building Information Exchange).
This is the method of working that has been set as a minimum target by the UK government for all work on public-sector, work by 2016.
The Office of Government Commerce’s “Achieving Excellence in Construction” initiative requires central government departments and public sector organisations to commit to maximising efficiency, effectiveness and value for money through continuous improvement. A holistic BIM approach aids this initiative through improved efficiencies, collaboration and waste-reduction.
The Future is BIM
It’s vital that the industry works with all stakeholders in the adoption and implementation of BIM and its continual advancement.
Major hurdles to widespread BIM adoption include lack of initiative and training, lack of awareness, reluctance to change existing work practices, the fragmented nature of the industry, and lack of clarity.
There are also legal concerns such as whether or not BIM models are contract documents. The industry needs to redefine current contract models to make BIM adoption and use much easier. This could be achieved by including appropriate clauses to deal with insurances, BIM model intellectual rights etc. Professional liability claims may actually decline in the next few years due to implementation of BIM.
The industry also needs to work proactively with universities to ensure that BIM modules are introduced into higher education curricula, reducing graduate training costs to industry.
Return on Investment
What about Return on Investment (ROI) of BIM? US case studies showed ROI ranging from as little as 15% to as much as 1600%. But perhaps we should look at the added value brought by BIM and assess the cost of not using BIM, i.e. the cost of not embracing new technology and changing our way of working for the better. Studies are also underway on how smart mobile devices can be used to add value to BIM.
We are also working with clients; educational establishments and key business partners to raise BIM awareness and promote an integrated BIM approach on projects. We expect more and more clients to start demanding BIM on their projects.