# A BIM-Enabled Workflow for the Rehabilitation of Heritage Steel Bridges
## 1 Introduction  
Transportation infrastructure is the cornerstone of economic growth, national security, and social well-being. Its reliability and safety in use directly impact the movement of goods and people, fueling economic prosperity and societal development. However, as these systems age, while the mobility demand grows, maintaining and rehabilitating transportation networks becomes a critical challenge, driving the need for innovative, efficient, and cost-effective solutions. Unlike buildings, transportation infrastructure, comprising roadways, utilities, and environmental assets, is inherently expansive and interconnected [1]. Three out of five domains within transportation infrastructure are characterized by a mesh network of assets, where longitudinal structures like roads, railways, and pipelines connect point structures such as bridges and intersections. This unique configuration generates significant differences in project breakdown structures compared to building projects. The expansive size of transportation networks necessitates greater reliance on Geographic Information Systems(GISs) to effectively map, monitor, and manage these assets. When integrated with Building Information Modelling (BIM), GISs can support the development of a powerful framework that can be employed to comprehensively address the challenges of infrastructure management. As shown in recent studies [2; 3; 4], the convergence of BIM and GISs facilitates the integration of non-graphical data (current condition assessment and maintenance schedules) into project models, enabling a holistic understanding of infrastructure assets like bridges and optimizing their lifecycle management. BIM can be seen as focusing on detailed, component-level design and data management, while GISs can be used for spatial analysis and geospatial data visualization. The integration of these systems closes the gap between localized design information and broader geographical context, allowing stakeholders to monitor and manage infrastructure more effectively. Moreover, this integration enhances decision-making by streamlining data flow between design, construction, and operational phases, as GISs can provide critical environmental and geographical data (e.g., flood zones or seismic activity regions), which, in turn, can inform bridge design and material selection in BIM. Conversely, BIM's detailed structural models can be layered onto GIS maps, offering a comprehensive view of how individual assets interact within a larger transportation network. Furthermore, data structures in transportation projects are more varied and interconnected, requiring a strong focus on integrating diverse information sources. This requirement is paramount for collaborative teams, often larger and more complex, to be able to account for the expansive scope of transportation projects. A key component of road infrastructure is represented by bridges. Emerging in the late 18 th century with the construction of the Iron Bridge in Coalbrookdale, steel structures have evolved through distinct phases--cast iron, wrought iron, and mild steel, with the latter becoming dominant. For Europe, a significant role in this evolution was played by Romania, with its steel industry taking root in the 18 th century. By the second half of the 19 th century, the Austrian Railways Company, STEG, had introduced modern steel production technologies in the western region of Romania, at Resita (Reschitza). The riveted steel bridges produced here stand as an innovative testament to the industrial revolution. This period noy only saw advancements in steel elaboration methods but also a broader recognition of steel's potential use in infrastructure, paving the way for the widespread use of this material. Recognizing that no structure is built to last indefinitely, developed societies have embraced the importance of maintaining architectural heritage to preserve cultural identity while ensuring functional infrastructure.