Philipp Hagedorn

Particulate matter (PM) emissions from construction activities affect urban air quality, worker exposure, and surrounding communities. Improving their management is therefore a relevant contribution to sustainability and reflects UN Sustainable Development Goals (SDGs) related to health and well-being (SDG 3), sustainable infrastructure (SDG 9), and urban liveability (SDG 11). Digital Twins (DTs) can support PM emission management by connecting monitoring data, site context, threshold information, and decision-support services. However, existing approaches still lack structured semantic workflows able to represent threshold entities, evaluate PM observations, and retrieve alert-relevant context. Building on a previous high-level DT framework for PM emission management on urban construction sites and on the Construction Site Emission Management Ontology (XEMO), this paper proposes and evaluates a semantic alerting workflow based on threshold modelling and SHACL validation. Thresholds derived from current and forthcoming European environmental air quality reference values are represented as semantic entities linked to pollutants, averaging periods, units, values, and regulatory sources. A demonstrator is then developed in which synthetic PM10 and PM2.5 observations are generated, stored as time-series data, transformed into semantic data according to the Resource Description Framework (RDF), integrated into a knowledge graph, and validated against threshold-based warning conditions through SHACL shapes. The validation reports are queried to retrieve the related alert context, including pollutant, measured concentration, threshold condition, sensor, construction area, and emission source. The results show the prototype-level feasibility of using semantic modelling and SHACL validation to support traceable PM alerting, providing a reusable basis for future decision-support services within semantic DTs and real-site implementation.

Reusing cast-in-place (CIP) concrete elements could enhance the sustainability of the construction industry by enabling circularity, preserving embodied value, and reducing primary resource consumption, construction and demolition waste, and emissions from new concrete production. However, the implementation of such reuse is hindered by project-specific geometries, monolithic connections, and complex coordination requirements. Existing process representations address individual aspects of reuse, but an integrated process framework for coordinating assessment, dismantling, logistics, and reuse across multiple actors and projects is still lacking. To address this gap, this study develops a concept for a process-driven digital ecosystem supporting the circular reuse of CIP concrete elements within the Collaborative Research Centre 1683. Literature-based process representations are analysed, translated into Business Process Model and Notation (BPMN), and synthesised into domain-specific process models. The resulting models formalise the reuse chain, clarify actor responsibilities and information flows, and support the identification of technical, temporal, and spatial dependencies. Building on this formalisation, a conceptual digital ecosystem is derived that links information on reusable elements with process logic and reuse-related decision-making. The concept centres on a construction kit (CK) as a standardisation layer and an element data store (EDS) as the information basis for traceability, coordination, and matching. The results provide a structured foundation for digitally supported sustainability-oriented circular construction and for future ontology integration, process simulation, and decision-support applications.

Abstrakt: Natürliche Prozesse laufen im Kreislauf ab. Auf Vergehen folgt gleichwertiges Entstehen. Solch ein Zirkularitätsprinzip ist im Tragwerksbau nicht verankert. Nach Nutzungsende werden Bauwerke abgebrochen, falls möglich zerlegt und recycelt. Besonders davon betroffen ist die Stahlbetonbauweise mit ihrem enormen Baubestand. Abbruch löst ein fatales Downcycling aus, mit minderwertigem Betoneinsatz als Schüttgut oder Deponierung. Selten besiegeln dabei Tragfähigkeitsdefizite das Nutzungsende, vielmehr sind Nutzungseinschränkungen oder baurechtliche Schranken ausschlaggebend. Die Folgen sind eine enorme Verschwendung an Ressourcen wie Sand oder Kies, Treibhausgasemission zur Aufbereitung und Abfall. Wiederverwenden (engl. reuse) bedeutet ein erneutes Nutzen von Stahlbeton als Bauteil (Modul). Nicht mehr genutzte Tragwerke werden dazu in die noch tragfähigen Anteile zerlegt, in ihren Eigenschaften charakterisiert, aufgearbeitet und baukastenartig zu neuen Tragwerken zusammengefügt. Es entsteht ein kreislauffähiges Modulsystem. Der Sonderforschungsbereich 1683 mit Sprecherschaft an der Ruhr‐Universität Bochum befasst sich mit dieser Art der modularen Wiederverwendung und erarbeitet Entwurfs‐ und Reparaturkonzepte für Tragwerke aus wiederverwendetem Stahlbeton, automatisierte Charakterisierungs‐ und Aufarbeitungsverfahren sowie Prozessmethoden für Logistik, Dekonstruktion und die Nachhaltigkeitsbewertung. Der Beitrag stellt die Konzepte und Demonstratoren möglicher Tragwerke vor.

Given the significant impact of the construction industry on climate change, efforts must focus on reducing energy consumption, emissions, and raw material extraction. Through improved planning and continuous design optimization, building sustainability and circularity can be enhanced. Significant progress has been made in the fields of Building Information Modeling (BIM) and Life Cycle Assessment (LCA). However, it is still necessary to meet the diverse BIM model requirements defined by LCA software vendors, whose proprietary Property Sets (PSets) must be enriched with information in the BIM model for accurate assessments. However, there are also open developments that have agreed on a common information requirement for sustainability assessment and circularity assessment available as datasets in the buildingSMART Data Dictionary (bSDD). This paper presents the development of an Information Delivery Specification (IDS) that combines the information requirements of two LCA software and two bSDDs. The IDS is successfully validated on two BIM models and will be further developed in an ongoing research project.