Currently, free loading, city logistics and a container terminal are located in an area of around 16 hectares at the Basel freight station, whereas in the future this area will contain businesses, offices and housing. In planning the new Quartier Wolf Basel, landowner SBB, together with the canton of Basel-Stadt, has broken new ground. Various studies were commissioned to estimate the amount of greenhouse gas emissions that could be avoided by reusing materials instead of buying new ones. For the architectural competition, concrete criteria are being developed for the economical use of existing materials and how to avoid or reduce emissions.

For SBB, this is another lighthouse project with which it is fulfilling its pioneering role as one of the largest contracting authorities in Switzerland, with annual procurements amounting to CHF 6 billion. Samuel Pillichody, general project manager at SBB Real Estate, reveals how SBB and its partners went about preparing a circular architectural competition for the Wolf Basel project and what they learned in the process.

Planning the end at the beginning: developing competition criteria in a team effort

Registering the existing buildings: BIM Facility created a BIM model from measurement data obtained from drones, scans and tachometers. In this model, the building components are not only recorded pictorially, but also as ‘objects’. Their mass and materials are described to a predefined level of detail. The BIM model provides information about the types and amount of materials used, where they are located within the building and how they could be retrieved and reused in the event of demolition.

Creating a material passport: The BIM model was registered on Madaster’s online platform, enriched with the information from the databases available there and presented in a material passport. These passports not only provide an overview of all materials and products used, their quantities and locations in the building, but also shows an index of the reuse potential of the materials as well as the degree of circularity of the buildings involved.

Analysing components and temporal relevance: The subsequent component analysis by Drees & Sommer provides information on material categories, disassembly potential and the risk of pollution related to the components. Particularly relevant for the architectural competition is the evaluation of the design relevance and identity-forming characteristics of the components. Old warehouse scaffolding or the SBB station clocks, for example, are highly distinctive features and should therefore be reused on site, if possible. Above all, the high potential for reducing CO2 equivalents and the ecological added value of reuse become visible especially in the finishing, the external wall cladding and in the construction/shell.

Circular criteria relevant for the competition: Circularity finally defines the circular economy criteria for the architecture competition. Criteria include a high proportion of reuse, design for disassembly, low emission level related to construction, durability and reusability. Another point of discussion is which level of stringency to apply to the criteria in the architectural competition without disproportionately restricting the creative designing process.

Lessons learned for the future from cooperation

SBB and its partners consider the project a success. Everyone was able to learn a lot about the realisation of circular economy in construction. One question in particular was often raised: what should be the level of detail of the data to be collected?

Digital consistency of data is essential for efficient collaboration. The type of data and level of accuracy must be right so that everyone involved is able to speak the same language. Architectural offices receive the ‘construction kit’ of available components to base their planning on. Components that are included in the material passport but are not reused can simply be consolidated and sold online on specific construction material market sites.

The example of the station clocks showed that clients need more experience when assigning the construction of a circular building. The clocks were not part of the BIM order and were therefore not recorded in the inventory. It was not until the component analysis was conducted that they were recognised as very interesting items for reuse, because of their distinctive character. In the future, clients would want to know which components need to be included in the BIM model component analysis. Early coordination between the developer of the BIM model and the subsequent component analysis is appropriate. The building owner must also be clear about the goals and the desired level of effectivity with respect to the circular economy. Measures will not all achieve similar goals.

From the discussions, it also became obvious that the current deconstruction processes need to be reconsidered. The standard procedure today is to demolish a building and then start planning a new one on a new site. In the ideal situation, however, the architectural design should be based on the available materials. To this end, the competition announcement should include the suggestion to include any materials from the deconstruction of the old building in the planning of the new-build property. It should also be possible to combine the deconstruction permit and the new building permit. In Switzerland, these permit are currently issued separately. Furthermore, issues of temporary material storage also still need to be addressed.

The architectural competition will start in the near future. The submissions will show new possibilities for circular construction. Projects such as Wolf Basel are fundamental to the transformation of Swiss construction. Shared learning and understanding form the basis for a sustainable Swiss construction and real estate industry.

SBB coordinates its activities in the area of circular economy in a competence centre for circular economy.

For more information, see the SBB website: https://company.sbb.ch/de/ueber-die-sbb/verantwortung/nachhaltigkeit/umweltschutz/kreislaufwirtschaft.html

Contact

• Daniel Zogg, Responsible for recycling management SBB Immobilien, daniel.zogg@sbb.ch
• Samuel Pillichody, General project leader SBB Immobilien Development Anlageobjekte Mitte, samuel.pillichody@sbb.ch
• https://www.bim-facility.ch/
• https://www.dreso.com/ch/
• https://zirkular.net/

Foto © SBB CFF FFS