Case study – The Four Administrations, Denmark

The first case study presented is a comprehensive concept of an office building in Copenhagen, Denmark, referred to as The Four Administrations. The following information is mainly collected and summarised from the book “Building a circular future” released in 2016 and republished as a third edition in 2018, as a collaboration between the authors Jensen Guldager and Sommer Kasper, and the Danish Environmental Protection Agency (Guldager Jensen & Sommer, 2018). The project was been designed by 3XN Architects, MT Højgaard, DEAS and Balslev, and it promises to change and enhance the way people think about both circular constructions and designing for disassembly. When approaching such an innovative way of designing and constructing a building, most of the attention is understandably directed to the expenditure aspect. This is an interesting and vital aspect, mainly because the common perception nowadays tends to be that circularity, or environmentalism in general, automatically results in extra costs without any economic benefits. The results of this project seem to speak against this perception since the building and its components are designed in a manner which allows them to produce value at the end of their life cycle when they can be resold and reused as raw material instead of ending up in waste. This relevant aspect has been taken into consideration during this project, and the results go against the common misconception that sustainable choices, although being more ethical, always end up having a negative effect on the budget. One of the reasons why a project such as The Four Administrations was needed, was to offer a real-life model to address the factor of

uncertainty regarding the expected value when applying a circular approach into the construction sector.

The Four Administrations, illustrated in Figures 10 and 11, is designed to be a turnkey bid project and its existence is to act as an example to future construction projects that want to tackle the idea of circularity as well as sustainability.

Fig. 10: Illustration of the aerial view of The Four Administrations building. (Guldager Jensen & Sommer, 2018)

Since circularity applied in the construction field is a relatively fresh concept, there is a certain risk factor when designing this way. This goes especially for large scale projects such as The Four Administrations. There is a higher risk when designing on a large scale with somewhat new technologies, approaches and even different end goals. This is another relevant reason why a concept like this is beneficial for the industry. A large-scale project creates incentives for construction companies to adopt similar kind of measures not only to large scale but also to smaller-scale projects.

The project has been created in collaboration with the Danish Government and is a Public-Private Partnership (PPP) which means that contractors have not only the responsibility of creating a design and the purpose of a building but also to integrate the operation and maintenance costs for the project over a period of 30 years. This

move undoubtedly forces contractors and architects to aim their attention not only to the construction costs but also to the Life Cycle Costs (LCC).

Fig. 11: Views of different sections of the designed building. (Guldager Jensen & Sommer, 2018)

The building

The project has a size of around 38.000 m² and a built value of DKK 860 million or € 115,5 million. As mentioned before, the primary design approach was oriented to an easier disassembly at the end of the building’s life cycle. The building was designed to facilitate four main Danish government agencies.

The structure has a load-bearing façade (Figure 12) along with concrete slab elements.

The load-bearing façade facilitates a certain freedom when designing the interior

offices and openings as it eliminates the need for interior columns. This also enables easy repurposing of floor areas.

Fig. 12: A sectional view of the façade. (Guldager Jensen & Sommer, 2018)

The foundations are built with the help of pillars, and the ground floor is made out of concrete which is cast on site. All the floors are made out of concrete slabs which are impregnated and polished with wax, thus giving them an industrial look but also facilitating cleaning and easy maintenance. Windows are built with wooden and aluminium frames, and between them, composite profiles that have both isolation and

condensation prevention characteristics are installed. Given the fact that the windows are in contact with the weather, they would have to be changed at some point during the building’s lifetime. For this reason, the frames are built in such a way that they can be easily disassembled when the time comes. The shadings are made from expanded metal and connected to the building’s body through screws rather than welding. Both the floor and roof slabs are made of 400-millimetre prestressed hollow core slabs which lay between the curtain walls. Steel composite beams are attached to facades, individual columns and shaft walls, and support the slabs. The partition walls are built to be movable, allowing the interior space to be adaptable to the client’s needs. The interior side of the external walls has a raw concrete finish that gives it a modern appearance and requires little to no maintenance as supposed to paint, which would need redoing every few years. The exterior walls are plastered with bricks which also require minimal maintenance when appropriately built. They are bound together with lime mortar so the bricks can be easily dismantled and reused. The different layers of the building can be better seen in Figure 13.

Fig. 13: Different layers and structures used in the building process. (Guldager Jensen & Sommer, 2018)

As seen in the illustration above, the ventilation and the cable beds have been designed to be installed in the floors thus further improving the flexibility of the interior space and avoiding protruding elements that might ruin the clean aspect of the room.

In order to design a building that would be effortless to assemble but also to

disassemble, fast to build and simultaneously cost-effective, the architects at 3XN Architects decided to utilise the method of standardised design (Figure 14). The final project plan included 72% of standardised elements which would allow the project leaders to save both time and money.

Fig. 14: The figure shows the extent to which the building is utilising standardised elements. (Guldager Jensen & Sommer, 2018)

The benefits gained from the standardised elements are manifold. Not only do they save time, and thus money, during the planning and designing process but they also offer an improved alternative to traditional design because they allow faster construction, reduce the time required to train the builders, require fewer different tools and finally enable less variation in design. All of these factors combined contribute positively to the effectiveness of the building process and are thus more economical.

Digitalisation

The usage of digitalisation was necessary to not only help with the designing and construction process but also to improve the recyclability of the building’s components.

Building Information Modelling (BIM) and Virtual Design and Construction (VDC) were the go-to processes utilised in order to reach the circularity goals of the project.

BIM is a well-known tool in the industry, and it is used to improve the construction projects by modelling and digitalising the designs, offering easy three-dimensional

visualisation of projects and their components. VDC, on the other hand, is a tool that includes information regarding the overall performance of the construction along with milestones and client objectives (Kunz & Fischer, 2020). One of the advantages of implementing VDC in a construction project is the fact that it assists in the progress of collaboration between the architect, construction company and client, thus facilitating a smoother designing process and allowing the early optimisation of the project.

Furthermore, the material characteristics collected and stored by the VDC can be later used as material passports and therefore become crucial during the disassembly and reusage phases. In addition to both of the electronic tools offering improvement and valuable data on their own, they can also be utilised together. The VDC tool enhances BIM by adding extra functionality to the table, such as managing the time schedule during the construction phase as well as adding explicit information needed for maintaining the building for its whole lifetime. It also completes BIM by adding relevant information regarding the types of elements used along with their characteristics.

One of the ways that BIM and VDC were utilised for the project of The Four Administrations was in the design and planning process of the connections and joints between elements. The links were designed in a way that they could be easily dismantled when needed. This meant that traditional joints had to be replaced with mechanical connections consisting of nuts and bolts. Using the two digital tools, an evaluation of the building was made in order to determine the most critical joints and their importance in both assembly and disassembly processes (Figure 15).

Fig. 15: Various joints and connections between building elements. (Guldager Jensen & Sommer, 2018)

Figure 15 illustrates the most frequently used connections between different elements of the building. These elements form the floors, ceilings, walls and columns. The digital

tools allowed the most critical and frequent areas to be recognised thus allowing more focus to be drawn to them. The main goal in the design process of the joints was to facilitate effortless and speedy attachment as well as detachment.

According to Guldager Jensen & Sommer (2018), in today’s construction sector and BIM, there are seven dimensions that need to be taken into consideration in the design process (Figure 16).

Fig. 16: The seven dimensions of a construction. Adapted from (Guldager Jensen & Sommer, 2018)

Figure 16 is a representation of the current and future BIM dimensions used in the construction sector. The first, second and third dimensions are the usual height, depth and width forming the basic structural measurements as well as a 3D representation model. The fourth dimension is related to time schedule allowing easier visualisation of the progress of construction. The fifth dimension is the integration of costs and quantities into the model. The sixth dimension incorporates relevant information into the model, which will later be necessary for the operation and maintenance of the building. This dimension is also used to ensure the optimal performance of the

building’s elements and their life cycle but also to give facility managers relevant information regarding the efficient usage of the building. The seventh dimension is, according to Guldager Jensen & Sommer (2018), the implementation of data that allows elements of the building to be reused when needed, be it at the end of the building’s lifetime, during an expansion or during renovation. Furthermore, the reusage of the elements would also mean that the owner, instead of investing for waste disposal, is now able to earn value when the time for deconstruction arrives.