What is BIM in construction?

BIM (Building Information Modelling) in Construction is a process that is used to convey a wide variety of information to all those involved in the construction lifecycle.

In the ideal case, this means using BIM in:

• Planning
• Design
• Construction
• Commissioning
• Operation
• Maintenance
• De-commissioning
• Demolition

Although the creation of a 3D digital BIM model is usually at the heart of the BIM process, it does not necessarily have to be so. After all, the most important aspect of BIM is the ‘I’ for Information.

That information can also take several forms, whether:

• Geometric, spatial and graphical – to define the extent, form and structure of a building or structure.
• Textual – to allocate attributes, characteristics, properties and metadata to elements of the project which have been or are being defined geometrically.
• Photographic/image-based – to provide information quickly and easily in a way that textual descriptions cannot e.g. to show the condition of an object.

With the ‘B’ in BIM standing for ‘Building’, the casual observer might be forgiven for thinking that BIM applies only to buildings and architecture. Fortunately, that is not the case and BIM is applied to many other disciplines involved in or brought into, construction, such as:

• Structural Engineering
• Building Services (MEP)
• Civil Infrastructure
• Manufacturing

Furthermore, although BIM is very much thought of as a process that is applied to ‘new build’ construction, it is also equally applied to the creation of digital models of existing buildings and structures for projects which involve extending, adapting, retro-fitting or upgrading to provide a new lease of life.

How is BIM used in Construction?

One of the big advantages of BIM in Construction is that it facilitates a more collaborative approach, especially at the design and construction phases, where multi-disciplinary teams are working together.

At the construction phase, a large contractor will typically be responsible for the ‘master’ BIM model, facilitating access to that model by a variety of sub-contractors.

This is achieved by means of a ‘common data environment’ (CDE). The CDE, managed by the Information Manager, is the single source of information for the project, and is used to gather in, and distribute out, all information relating to the project.

This collaborative way of working – the so-called ‘Level 2 BIM’ – is mandated by the UK Government for all public sector projects.

Level 2 BIM allows all of the project participants to develop their own 3D CAD models covering their particular aspect of the project. Theoretically, at Level 2 BIM, each participant can use whichever software it likes to work up its designs, as long as the output is fed back to the Information Manager through a common file format. The uploading of the various models back into the ‘master’ model creates what is known as a Federated BIM Model, managed by the main contractor.

In practice, the main contractor may insist that all subcontractors use ‘approved’ software or, at least, provide their output in a particular file format for ease of uploading back into the federated model.

There are multiple benefits that arise from working via a single, federated model, the most obvious being:

• Design coordination
• Clash detection
• Clash avoidance

The federated model also facilitates quantity estimations and costs, schedules and reports, and, using COBie (Construction Operations Building Information Exchange) ‘drops’ (deliveries of data), population of asset registers with non-graphical attribute data for use by the project owner when the completed project is commissioned. An example of this would be future maintenance dates and schedules for installed items of equipment.

Example of BIM in Construction

The Sir William Henry Bragg International Centre for Engineering and Physical Science (ICEPS) at Leeds University is a recently completed facility that brings together the faculties of Engineering, Physics, Chemistry, Materials Science, Astronomy and Computing along with the provision of central teaching and social spaces.

The 15,700m2 building includes laboratories, clean rooms and close temperature control rooms accommodating high-resolution electron microscopy, surface probe microscopy, X-ray diffraction and Raman & Terahertz spectroscopy.

The main contractor, BAM Construction, was awarded the £96m project in March 2018 and, with so many disciplines involved, it was always going to be a BIM construction project.

A key supplier to this project was Cambridge Fluid Systems (CFS), a leading provider of sophisticated, fabricated gas and liquid control systems working with high technology industries, such as Semiconductor, Photovoltaic, Pharmaceutical, Aerospace and Energy.

Benchmarq was asked by CFS to:

• Assist with the 3D modelling of special gas lines being supplied to the Clean Room labs in ICEPS. These gases include Argon, Neon, Helium, Oxygen, Trifluoromethane, Nitrogen, Tetrafluoromethane, Sulfur hexafluoride, Chlorine, Methane, Hydrogen, Silane, Hydrogen bromide, Nitrogen trifluoride, Ammonia, Nitrous Oxide.
• To coordinate that model with other M&E contractors working on the project, all being managed by BAM Construction through their internal system (livelink) and Autodesk 360GLUE.
• Provide verification and confirmation of key dimensional information to the CFS installation team as work progressed.
• Populate the developed Revit families with attribute data (meta-data) in readiness for export out via COBie drops as part of the creation of an asset register for the owner of the building, the Estates Department of Leeds University.

Working from 2D AutoCAD drawings and components created originally in Solidworks, Benchmarq created 3D model layouts in Revit 2019 of the single bore and coaxial stainless steel pipework to be supplied by CFS, along with other items of equipment such as isolation valves, valve manifold boxes and various items of bracketry.

Most of the CFS pipework had to be threaded in the 600mm sub-floor space beneath the cleanroom, itself supported on props at 600mm grid spacing. In addition, the incoming supply lines had to be threaded through congested areas in the ceiling void above the cleanroom, ensuring that not only could the pipework be located correctly to avoid clashes with other services but that the viability of installation was also maintained.

All of this was coordinated weekly with the master Revit model held by BAM, involving multiple other services such as water supply and drainage pipework, heating, cooling and ventilation ductwork.

The Leeds ICEPS project is a great example of how BIM helps construction. The Benchmarq team worked extremely closely with the CFS designers and installation team, at times providing real-time confirmation of critical spacing and dimensions for the installers as they worked.

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