New methods and technologies are changing the engineering and construction sectors. Let’s explore I-BIM, the Information Modeling of Infrastructures.
Technological innovation is significantly shaping the landscape of infrastructure construction. In this context, Infrastructure-Building Information Modeling (I-BIM) emerges as a powerful digital tool, distinct from traditional BIM, focusing specifically on infrastructure construction. This approach integrates infrastructure peculiarities, such as their horizontal extension and network complexity, into a digital information model. It goes beyond mere physical representation, incorporating functional and managerial data crucial for effective infrastructure planning and management.
Challenges and Opportunities of Information Modeling of Infrastructures
Despite its considerable potential, implementing I-BIM presents challenges. Interoperability and data standardization through Industry Foundation Classes (IFC) are vital for efficient information exchange among different stakeholders in the construction process. However, the increased complexity of parametric infrastructure models coordinating with various contextual territorial models undoubtedly poses a significant challenge.
Standardizing these models required surpassing the IFC 2×3 standard used for architectural building modeling. It led to the creation of the new IFC 4.3 standard tailored for proper geometric and informational representation of infrastructures like roads, bridges, etc. The IFC 4.3 format is a milestone in I-BIM, providing a defined and flexible structure for infrastructure representation. With detailed definitions and the ability to model complex infrastructure projects, IFC 4.3 is a significant step toward automating and optimizing infrastructure lifecycle. There are also tools like software to convert an IFC 2×3 model into an IFC 4.3 file that can be incredibly useful in this phase, or software for comprehensive editing of an IFC file.
IFC 4.3: A New Standard for Infrastructures
In the realm of I-BIM, the IFC 4.3 format is a significant milestone. This new version introduces a wide range of definitions to represent infrastructural construction projects in a structured and understandable manner.
Critical in this context is the use of Work Breakdown Structure (WBS), which not only enhances the design value but also facilitates understanding and interaction with the project by all stakeholders. Establishing common standards through IFC 4.3 helps simplify processes across the entire project lifecycle, enhancing system adaptability, defining design requirements, validating digital models for various purposes.
The new features of the IFC 4.3 standard include:
- Spatial Structure – Maximum flexibility in creating complex spatial structures as per model use. This differs from the previous version where the spatial structure related to buildings was relatively fixed.
- Alignment (Semantic + Geometric) – Fundamental for defining linear infrastructure, Alignment allows defining the path by breaking it down into its Semantic and Geometric parts, particularly defining horizontal, vertical curve profiles, and cant (elevation).
- Parametric Extrusions along Alignment – Ability to define solids based on predefined profiles (e.g., rails, ballast, sub-ballast, etc.) to and from precise points along the path.
- Linear Object Placement – Ability to define object position not only through its X, Y, Z coordinates in space but also its position along the Alignment, with potential lateral, vertical, and/or longitudinal offsets. This also implements the concept of “stationing,” indicating an object’s kilometric position (e.g., this signal is at km 3+200 along a specific path).
These new concepts, crucial for linear infrastructures, integrate with existing concepts like:
- Assemblies and Decompositions – Useful for deciding the object decomposition level; for instance, a traffic light could be broken down into the pole and the actual light.
- Properties and Groups – Properties define the necessary information level, while groups help create cross-sectional groupings added to spatial decomposition.
- Doors and Connections – Mainly for wiring, sewers, etc., adding further semantic information to the model.
Combining all these elements, along with new IFC classes defined for objects in each infrastructure domain (e.g., sleepers or rails in a railway context rather than signals in a road context), enables creating an IFC model rich in all the necessary information for asset linear digitalization.
The IFC 4.3 standard is currently in the final “FDIS” approval phase to attain international accreditation as an ISO standard. The FDIS voting process is expected to conclude this year, allowing publication by early 2024.
Classification and Definition of Objects in IFC 4.3
Specifically, IFC 4.3 categorizes elements of an infrastructure project into three primary thematic groups:
- Objects (ifcObjectDefinition): Encompass tangible physical objects like structural components, stakeholders, processes, and costs.
- Properties (ifcPropertyDefinition): Information and characteristics that can be associated with objects.
- Relationships (ifcRelationship): Interdependencies and connections between various objects.
An actual example is ifcProduct, an abstract entity representing any object in a geometric or spatial context, such as physical products, spatial elements, and even non-physical elements like annotations and alignments.
Here’s a video on creating the informational structure of an IFC 4.3 file:
Example of Road Models and their Representation in IFC 4.3
Focusing, for instance, on road models, IFC 4.3 allows describing these complex projects through entities like ifcSpatialElement, ifcElement, ifcLinearElement, and ifcPositioningElement. For example, ifcSpatialElement represents the spatial division of a road project, including elements like roads, bridges, tunnels, allowing project division into different areas or sites.
This division aids coordination among various project stakeholders, from design to construction. Each area encompasses the design and construction of different objects, ranging from tunnels to bridges, railways, roads, buildings, to technical devices.
Physical Components and Annotations in IFC 4.3
Concerning physical components, ifcElement includes elements constituting the physical structure of a road, like pavements, curbs, open ditches, etc. Additionally, IFC 4.3 enriches the representation of these structures, offering the ability to further detail object division through subcategories like ifcBridgePart or ifcRoadPart.
Annotations (ifcAnnotation) play a crucial role in providing supplementary information, like pavement layer edges or other components vital for surveyors and other project-involved professionals.
Professional Profiles and Training in Information Modeling of Infrastructures
The adoption of I-BIM has stimulated the creation of new professional profiles and the need for specific training: roles like BIM Managers and BIM specialists have become essential to ensure proper usage and efficient data management in infrastructure projects. This evolution demands contracting authorities to have adequately trained staff, not only for effective I-BIM use but also to ensure tendering aligns with the technology’s new requirements and potentials.
A certification for skills validation is therefore essential. This is carried out by specific Certification Bodies upon completion of BIM training and certification courses.
Case Studies and Practical Applications of Information Modeling of Infrastructures
A Practical Case
RFI, Italian Railway Network, expressed the need to digitize an existing railway asset, the Benevento-Cancello line, approximately 50 kilometers, for maintenance purposes, using the new IFC 4.3 standard. To address this need, a working group involving participants from RFI (Italian Railway Network), EAV (Ente Autonomo Volturno), ETS Ingegneria, University of Naples Federico II, and ACCA software was created.
A digitization process was developed using laser scanner technologies for point cloud production, drone usage for textured mesh production of stations and geolocated and 360-degree photos to navigate through.
The next step involved producing an IFC model, starting from the track geometrization obtained from the point cloud and based on the client’s specific requirements: creating a library of reusable objects and typologies, properties and typical characteristics of each entity, as per the information specifications. These decisions were made by the stakeholder and form the basis for connecting and integrating the IFC 4.3 model and the CDE with existing Asset & Facility Management systems.
The project was finalist at the buildingSMART Awards 2021 in the Asset & Facility Management category.
These projects have demonstrated how I-BIM can enhance efficiency, reduce errors, and optimize costs, leading to better infrastructure lifecycle management. Moreover, I-BIM adoption has fostered greater collaboration and communication among the various stakeholders involved in projects.
The Future of I-BIM and Its Implications
I-BIM represents a significant breakthrough in the infrastructure construction sector. Potentially enhancing infrastructure efficiency, quality, and sustainability, I-BIM emerges as an essential tool for the sector’s future. As technology and standards evolve, it’s highly likely we’ll witness increased application and integration of I-BIM in infrastructure projects, benefiting both the public and private sectors.