Abstract :
[en] There is no doubt left that the modern style of living is detrimental to the planet and the environment. Unsustainable consumption has overstretched the planetary boundaries. Earth’s resources are in danger, especially in the construction industry, where the most environmentally polluting materials made are also the most prevalent: steel and concrete. The construction industry is reportedly one of the largest, most polluting and resource-intensive industries with a substantial negative contribution to greenhouse gas emissions. Despite the ever-increasing awareness that all industries need to be less carbon-intensive and more resourceful, the construction industry is a polycephalic entity with unmatched desires. On the one hand, there is an urge to reduce the material input of the buildings; on the other hand, there is a need to build more buildings to host an extra 3 billion people on the planet in the next few decades. Meanwhile, the global community has pledged to keep the temperature rise well below 1.5 °C, which means carbon emissions should be better managed and lowered as much as possible. This situation is further exacerbated by the fact that there is also a material shortage combined with a price increase – two forces that are working in different directions. To diverge from the current take-make-waste model in a linear economy, a new paradigm has emerged that is called a “Circular Economy.” In the construction industry, a circular economy promotes everything to be designed with less materiality in such a way that they can be easily reused in difficult times. A circular economy aspires to take the existing business models from extreme resource consumption to an economy of sharing exiting resources between stakeholders and through creating new sub-cycles to avoid waste generation. For this new paradigm, new actors are introduced including “Material Banks,” who are regulators and moderators of materials between the early design phase and the End-of-Life (EoL) cycle phase in the construction industry. Material banks enable the transition to a circular economy from a linear economy. Not only do they help with linking discarded material to a new user, but they also enable legal frameworks to be implemented on the new subject of reusability. Moreover, re-certification of deconstructed material for reinjection into the value chain is in the envisioned jurisdiction of material banks. However, prior to the present thesis, there were no existing material banks that were object-oriented and enabled the connection to digital models, i.e., Building Information Models (BIMs). On top of that, the BIM tools did not have the capacity to semantically contain any data related to the EoL phase of construction products or environments. While circular economy is a new paradigm in all industries, BIM, too, is a new digital paradigm adopted in the construction industry. Relying on this identified gap and motivated by the urgency of circular paradigm, this research worked on the following hypothesis: How can a BIM exchange information with a material bank in order to ensure reuse after the end-of-life cycle? Dissected into three parts; (1) establishing the information needed to discuss circularity and reusability, (2) creating a formal ontology based on Linked Data as the exchange vessel of information, and (3) developing a material bank and demonstrating its successful implementation through the application of the two previous steps. First, a set of information that or needed to define circular transformation or end-of-life possibilities of different levels of circularity is captured. This step is done through triangulation methodology. Through extensive literature review, all of the information that is necessary for communicating if an item is reusable or not and making decisions based on the information for, e.g., digital diagnosis, are identified and crossmatched with established works such as BAMB. Not only are circular information needs the objective of this step, but also defining “reusability” is another goal. Using a qualitative approach, through semi-structured interviews with international experts in circular construction, the information needed for exchange and discussing if an object is reusable at the EoL phase is triangulated. Furthermore, the perspective of experts on the subject of reusability definition was investigated. The previous steps were performed in order to create a reliable taxonomy for circular transformation as a basis for semantic interoperability because the next objective of the hypothesis targets the exchange of circular information between BIM and material banks. The taxonomy, in the next step, is mapped to the RDF model, which is the building block of the Semantic Web technology. Consequently, the Decommissioning and Reuse (DOR) ontology, which is an OpenBIM paradigm based on Semantic Web technologies, is proposed for model enrichment and information exchange. This ontology is evaluated syntax-wise, and in the last step, a digital material bank, called Semantic Material Bank, is created as a proof-of-concept to show the application of DOR. This proof-of-concept is an information exchange platform that exhibits how the flow of information for circular transformation could be performed. Such an OpenBIM-based material bank not only fills the gaps in the literature but also demonstrates a scalable and interoperable solution that connects construction projects through space and time. Through space, because urban mines can exchange reclaimed material with each other, but without interoperable digital infrastructure, the digital silos of each urban mine remain disconnected, and their available materials are undiscovered. Time, because the time gap between the construction phase and the deconstruction phase is a matter of decades, almost as long as the building owners’ lifetime. Therefore, it might take a long time for a circular material to reach the next user. For this reason, a material bank must be able to future-proof the life cycle information and protect it against data obsolescence. These issues are discussed and addressed with the Linked Data approach throughout the present work. In the last steps, it is discussed how the Linked Data and DOR ontology could create a universal material bank through interoperable and standardised solutions by connecting the urban mines to each other. In conclusion, the construction industry's contribution to greenhouse gas emissions and resource depletion cannot be ignored. By leveraging the power of digital technology and adopting a Linked Data approach, the construction industry can transition from a linear take-make-waste business model to a more sustainable and resourceful one. The Semantic Material Bank and the DOR ontology provide practical solutions that can help construction projects exchange information and facilitate the reuse of reclaimed materials, ultimately reducing their environmental impact. Moving forward, it is crucial to have interoperable tools to encourage industry-wide collaboration towards a more data-driven and sustainable future. The DOR ontology proposed in this research provides a scalable and interoperable solution for exchanging circular information between construction projects. This study concludes that the digitalisation of circular construction and material banks has the potential to minimise the environmental issues caused by unsustainable resource consumption, waste generation and climate change.
