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October 23, 2018
Heritage & Conservation

RIAS Conserving the Assets of Our Past Seminar

Heritage & Conservation

RIAS Conserving the Assets of Our Past Seminar

As part of the recent RIAS Conservation Seminar “Conserving the Assets of our Past” Marianne Partyka and Justin Fenton of Page\Park Architects outlined the theoretical benefits and practical process of using Building Information Modelling for traditional building and historic environment projects. The following is a summary of the discussion.

Building Information Modelling, (BIM) is not just about drawings and pictures. Today, we have the ability to access and manipulate vast amounts of information in a way that was previously unimaginable. Within our conservation work, this is particularly relevant as we are not only dealing with information relating to the future of a project but also a project’s past. The challenge, as architects, is to effectively manage this data productively to the benefit of a project in time, cost and quality but also throughout its lifecycle. BIM provides the structure and foundations to efficiently organise and access considerable amounts of information for a project’s betterment.

A key element of BIM for us at Page\Park, when working with the historic environment, is the associated Common Data Environment, (CDE). The contents of the CDE are not limited to assets created in a ‘BIM environment’ and can, therefore, include documentation, graphical model and non-graphical data, (including tangible and intangible values). The information associated with a model informs our conservation work and can assist in the management of heritage and facilities. The model becomes an archive and information source, to aid management, research and future investigations: The BIM model then contains the Conservation Statement, Statement of Significance and Conservation Management Plan in a data coordinated location.

The starting point for the Historic BIM, (HBIM) process is a thorough knowledge of the existing asset. This is not unique to the BIM process but is a prerequisite for any conservation project. Documentation of the existing fabric, paying particular attention to accurate metric data is essential. HBIM should be based on accurate as-existing metric survey datasets, preferably in 3D.

There are various scanning methods available, but the one that we use most frequently is point cloud laser scans. This captures large volumes of high-resolution point-cloud data covering all visible surfaces of a building.  This is then used as the basis for creating native 3D geometry in a BIM environment such as Revit. This native 3D geometry is ‘dumb’ with very little information attached. Then, we connect additional information to each one of those objects or group of objects.

The PAS-1192 framework sets out the requirements for the level of model detail (the graphical content), model information (non-graphical content, such as specification data), model definition (its meaning) and model information exchanges. Specifically PAS-1192-2:2013 outlines an information delivery cycle. This, in many ways, mirrors the RIBA Stages of work, and as with the RIBA stages, within our conservation work, this is a cyclical process. So, we work through the steps of work developing a project information model, (PIM) at the end of which we have an asset information model (AIM). This AIM contains Documentation, Non-Graphical Data and a Graphical Model. Particularly with conservation work, this AIM, linked with the Conservation Statement, Statement of Significance, and the project drawings and specifications remain coordinated and “connected”, for the next phase of change management to work through the RIBA stages again.

At the outset of the Glasgow School of Art, (GSA) project, before the most recent fire, it was clear that a critical challenge for the reconstruction was harnessing the considerable quantity of historical and physical information available to us. GSA archives and collections have a vast archive of information relating to the building, including original bills of quantities, architectural drawings, Governors minutes and photographs from the last 100 years of the building’s existence. Cataloguing this vast quantity of information, along with archaeological data, and onsite measured surveys created an overwhelming challenge for our researchers and critically, for the broader project team, who needed a method of quickly and efficiently accessing the right information at the right time to aid the technical reconstruction. It was clear that the project required a complete refresh of how we handled, analysed, and importantly, made use of large quantities of historical and archaeological information in a way that would benefit the reconstruction. It became clear that this information must be well catalogued and managed to create a productive learning tool for future generations and the benefit of the building.

Our solution was to create a cyclical working process, with BIM as the binding element of three main areas of focus. Rather than viewing research, production information, and construction as distinct elements, we have identified them as three working areas, all of which must inform one another, and all of which have a unique output:

Research – We called the research area of the project our library, as it was an expanding resource that we referenced throughout the project. This area of work involved the exploration and collation of relevant archival sources to enhance the quality and accuracy of the reconstruction. As an output, we created a comprehensive set of documentation (Atlas), which informed our conservation philosophy, and recorded the condition of the fabric, the works required, and recommendations for the future. This was collated on a building-wide, space by space and piece by piece basis.

Design Studio – The production of technical and design information was referred to as our Studio, and was where BIM, as a design tool and repository for all project knowledge became preeminent. This work relied on the outputs of the other areas to inform what we designed, drew and ultimately what was built.

This included our fellow consultants. Working in a 3D environment is particularly beneficial for the intelligent integration of modern services into historic fabric. The design team involved with the reconstruction project were all working in a BIM Level 2, 3D environment, including David Narro Associates structural and Harley Haddow services engineers. At GSA we worked hand in hand to ensure that service routes were thoroughly designed and modelled to a degree of detail far in advance of a regular project. This was a time-consuming process. However, it minimised unnecessary disruption to the fabric, and, where possible, allowed for the concealment of contemporary services in creative ways. This process, combined with ‘clash detection’ allowed for the elimination of unwanted conflicts between service runs and other built elements, both existing and proposed.

The output of the “Design Studio” is a comprehensive PIM model and AIM.

Prototypes / On-site Investigations – This was the live site environment, where intelligent and informed propositions were thoroughly tested, improved, and finally realised. Lessons learned from prototyping in real life fed back into our working studio to refine proposals.

This process was cyclical, as no element is ‘complete’ until the end of a project and even then has a life beyond the immediate, instead, the main focus shifts throughout the project timeline. Everything that is learned from archive research and from real-world sampling and testing feeds into the BIM, both in terms of information, and refined design and specification. The work in each area is never in isolation; rather it continuously enriches the output of the others. The end goal is to deliver a highly detailed BIM for Facilities and Asset Management as well as for future learning and understanding.