Editor’s Note: I have a personal connection to this project as I stayed at Lucy Cavendish when I attended Cambridge University. (I loved it!)
The new building project for Lucy Cavendish College, Cambridge — designed to house the increasing number of students being admitted — is currently on site and due to complete Summer 2022. It will provide 72 study-bedrooms clustered in different combinations, with a variety of environments for social interaction. Four bedrooms will be fully accessible with caregiver accommodation alongside. The ground floor will act as a hub of differentiated informal learning spaces and will contain a large café/bar.
Wellbeing has been an important design principle – all study bedrooms, for example, have views of the gardens – and students have been involved in design workshops using virtual reality headsets that simulate the size, layout, and facilities of the study-bedrooms and social areas (Figure 2).
The building is being designed and delivered as a Passivhaus scheme, which means low energy in use and high comfort. The design energy targets are in line with those used in industry carbon-zero frameworks from the RIBA (Royal Institution of British Architects), LETI (London Energy Transformation Initiative), and the UKGBC (UK Green Building Council). The design eliminates the use of fossil fuels by utilising Air Source Heat Pump technology to provide space heating and hot water.
The entire project team includes:
The main software application used by RHP for the project was Autodesk Revit with some initial massing modelling in SketchUp. As architects, we use Autodesk Revit for all BIM projects, which make up at least three quarters of our project work including new build, retrofit and conservation work (Figure 3).
Some of the applications used by other members of the design team include:
Due to the use of different platforms (as well as different versions of Revit) we agreed to use IFC2x3 as the primary exchange format between disciplines (Figure 4).
In addition to design software, we also used Enscape for rendering. The real time rendering engine was incredibly valuable during concept stages to test design ideas and produce more understandable rendered images which stakeholders – including the College client team, Local Planning Authority and public – could readily understand (Figure 5).
We also used Enscape to power VR rendering of key spaces in the building including bedrooms and social spaces, which enabled us to provide a more immersive experience for the College during consultation with staff and students using our Oculus headset and a projector for people to see what the VR viewer was displaying.
In latter stages we used a combination of Enscape and Autodesk BIM 360 to support more detailed design coordination with the contractor and subcontractors to walk around the 3D building and better understand some of the complex geometry.
Although not a formal requirement of the client, we developed a “BIM ‘Lite’ Execution Plan” early in the project to decide on coordination workflows and information exchange requirements with design team consultants.
This streamlined our design development workflow and allowed other consultants including M&E to develop three dimensional designs at a strategic stage to really test the intended construction methods and approach.
It was a contract requirement for key subcontractors, including the Cross-laminated Timber (CLT) manufacturer and building services, to complete the design and coordination using Revit to enable effective review and coordination of information. This required front-loading the design effort to develop a high level of detail at an early stage, in particular to coordinate openings in the CLT structure prior to offsite manufacture.
Due to the complex layout and shape of the building (designed to complement the Conservation Area context), this proved incredibly useful and minimised clashes or errors once the project was on-site.
This was apparently the first time the CLT manufacturer, one of the largest in the UK, delivered design information in 3D using Revit.
It was also a learning experience for the design team, exploring options for estimating the embodied carbon of the design and ways to link the 3D coordination model to the PHPP model required to evaluate the project for Passivhaus Certification.
The biggest challenges was time! Due to an ambitious programme for delivery, the project progressed at a fast pace to ensure completion on schedule.
A more practical issue was information exchange with consultants using different software platforms. Architecture and M&E were both developed using Autodesk Revit, so coordination was relatively simple; however, the structural model was only available to us in IFC format since the engineers used Bentley software. There were a few teething problems due to the ways Bentley exported IFC and Revit interpreted the data. Specific examples included geolocating the model, and something we started to call the ‘hedgehog effect’ which caused all openings cut in the structural model to appear as extrusions! (Figure 6)
We worked collaboratively with our fellow design consultants to develop workarounds and eventually resolve issues with a viable workflow.
In an ideal world, analysing the environmental performance of the project would have been made easier if there was built-in support for transferring information from Revit to the Passive House Planning Package (PHPP).
We researched third party plug-ins such as Passivlink; however, one of the key concerns is modelling the correct level of information to input into the PHPP. As the project developed in greater detail, we knew that the model would become too complex for transferring geometry. For example, the PHPP doesn’t need to know furniture layouts or the thickness of door architraves! As the project was progressing at a fast pace, and this was our first Passivhaus certified project, we decided to create a parallel model using DesignPH, a plugin for SketchUp, to extract the relevant information for the PHPP (Figure 7).
Although the client team didn’t require formal Building Information Modelling or Asset Management deliverables, following the workflows we established for other projects, particularly for coordination and information sharing, certainly saved the team time during the design stage. It also helped eliminate and reduce impact of any coordination issues once the project was under construction. Due to the offsite manufacture of the CLT superstructure, this required a lot of upfront effort from the M&E Building Services subcontractor and liaison between architecture, M&E, the Main Contractor and CLT manufacturer.
Due to the complex geometry and technical demands of achieving the Passivhaus standard, we would have spent much more time working out “how” to communicate information, rather than working on “what” we needed to communicate, if we had not used BIM and other AEC technology applications. Using these tools also allowed us to spend more time coordinating and refining the design. Additionally, we were able to support the client with informed decision-making, using streamlined 3D visualisation and VR, to help stakeholders understand the developing design.
Kevin Myers and Tom Foggin are Directors at R H Partnership Architects, a UK-based award-winning architectural practice with design studios in Cambridge and Brighton, and a collaboration hub in London.
Kevin has been particularly active within the education and conservation sectors. His inclusive approach with stakeholders has involved close liaison with CABE and English Heritage on several schemes. Kevin regularly offers a pivotal role on projects with particular skills in conceptual design and clearly communicating these ideas with clients and colleagues.
Tom is an architect and certified Passivhaus designer with experience across a range of sectors including education, residential, healthcare, and cultural venues. As Sustainability Lead, Tom chairs RHP’s in-house Sustainability Group. He also has over a decade of experience successfully delivering BIM projects for a variety of public- and private-sector clients.
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