A £22m project to remodel two schools and build new facilities including a special needs school, Habberley Learning Campus is certainly a BIM early adopter. Speller Metcalfe won the contract due to the happy coincidence of writing its internal route-to-BIM roadmap just as the client was working on its own BIM implementation programme. So when Worcestershire council staged a mini-competition for the three contractors on the West Midlands Contractor Framework in autumn 2011, the BIM preparation paid off.
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Due to start on site this month, the Passivhaus project has already been nominated for a Building magazine Award for its use of BIM. “It’s an interesting case study of how a local authority client can engage with contractors, and take BIM down the supply chain,” says environmental manager Adrian Speller.
The project’s BIM approach has been aligned with the client’s from the start. The integrated architectural, structural and M&E design models were all produced in-house by the council’s design unit in Autodesk Revit, and Speller Metcalfe’s Ecobuild team — in effect acting as a buildability adviser during the design development phase – also purchased Revit licences to be able to change the model.
The model sits on the client’s servers, rather than being remotely accessible via the cloud. But there was still a need for an agreed BIM management standard, setting out how the parties would use BIM and defining design responsibilities, such as signing off final designs that have been produced collaboratively.
The team uses a cloud-based solution for all other document sharing, via the Microsoft SharePoint portal.
Wyre Forest SEN school (top), and a ground floor plan of the science block
The Revit BIM data was also exported into environmental analysis packages to assess options on daylight, energy and Part L, although Speller anticipates that future iterations of Revit would be able to run these calculations directly. The BIM model was also interrogated for quantities take-off to create the initial cost plan, and then – in the later value engineering stage – to reflect changes in quantities and repricing. “It’s certainly made the value engineering process easier,” says Speller.
The contractor has also taken the BIM model down its supply chain. When tendering for four timber-frame design packages, it shared the Revit model data with bidders, which could view it using Navisworks Freedom Viewer “read only” viewing tool.
Once on site, Speller believes the advantages will lie in being able to analyse design details, without asking the architects to produce new drawings. “It might throw up new problems, but it’ll give the site team more information to use on site,” he says.
The model was also linked to Asta program management software, allowing the team to produce animated versions of the week-by-week construction sequencing. “It’s about telling the Revit model which bits will be built in the construction programme that week,” adds Speller. “It will be useful in project reports, or if you want to open the door of the site office and check to see if what’s on screen matches what you see!”
On efficiency gains so far, the team has used 3D views direct from the BIM model for public consultation events, and there was a six-week saving in the production of planning drawings. The model was also used to produce the door and window schedule, and was linked to a 3D topographical survey, allowing the contractor to calculate the cut-and-fill soil quantities, and work out where to store soil on site.
So have the cost savings promised by BIM actually materialised? Viewing the project as a standalone, it’s likely that Speller Metcalfe’s fairly modest efficiency gains will be cancelled out by the £25,000-£30,000 costs of software licences and staff training.
But in the wider commercial sense, it’s clear that Speller Metcalfe’s BIM journey has been worthwhile. Since winning Habberley, it has used its BIM modelling capabilities to win two design-and-build projects.
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