Like other business, the construction industry is also moving towards digitalization. Building Information Modelling or BIM is an essential technological step, like 3D printing, virtual reality and drone mapping, playing an important role in the construction sector. BIM is best known for optimizing the planning process. It is mainly used to plan, implement, manage and decompose the digital model in the entire construction process.
The term BIM (Building Information Modelling) was introduced in 1992. Some countries have clear BIM strategies and guidelines. Germany and Europe have benefited in pilot projects and road map with the help of BIM. The technology is expected to become mandatory for large infrastructure all around the globe.
Though the geographic information system (GIS) has less involvement in the construction sector or mostly seen as a rival to BIM. In reality, the combination of both technologies can bring a drastic improvement in the overall sector. The experts of GIS can provide important information regarding the environment, and it can be helpful to the BIM experts for in the whole construction process.
This essay proposes the idea of the integration of BIM and GIS with practical examples form the A99 (name of highway in Germany) expansion pilot project in Germany. This is a practical demonstration of the integration of BIM and GIS to initiate a design process with ecological impacts
The A99 Expansion Pilot Project
A99 is the pilot project to expand the eight-lane of Autobahn A99. The focus of this project is to measure the flow of information among stakeholders and to assess the lifecycle of the project and its impact on the environment
Methods and Workflows
BIM and GIS Interoperability
GIS and CAD are two different software used in the construction sector. CAD is used by engineers and architects to design the project and GIS is used by the professionals to analyze the environmental impacts of the project. For efficient results, CAD database can be integrated with a GIS database.
Integration of BIM with geodatabase can result in a quick exchange of information among stakeholders. This can be useful for engineers to implement their civil engineering project, particularly urban and rural development projects. The data model of BIM and GIS can be integrated into parts or full to assess the environmental cost of construction projects.
Fig. 1: The integrated data exchange concept
Figure 2 shows schematically how the layer structure of GIS base data, environmental data and BIM data were combined (from bottom to top) in a 2D/3D geodatabase for the A99 project. The applied GIS technology allows the combination of each layer in this dataset and the assessment of any impacts between relevant 2D or 3D data layers.
Fig. 2: Integration of BIM data and GIS environmental planning data
ArcGIS Pro was used for 2D and 3D GIS data processing. Esri’s 3D modelling solution was used for the development of procedural modelling script. 2D vector, raster, 3D TIN and GRID data were used for GIS analysis. Following steps were performed to use the GIS data for analyses: topology validation and semi-automatic repair, data enhancement and creation of 3D geometries.
BIM / CAD
For modelling and planning the A99 expansion, Autodesk Revit, Autodesk AutoCAD, Solibri Model Checker, Linear Project TILOS, and RIB iTWO, software products were used. Processing this BIM planning data involved using the ETL process to split up the IFC (Industry Foundation Classes) data models into their components, transform them into Esri multipatch data format (while retaining their attributes) and write them into a geodatabase.
Import / Export Workflows
The Esri data interoperability extension workflow facilitated the data flow from BIM into GIS and back from GIS to BIM (Figure 3 and Figure 4). BIM geometries were read in IFC format, transformed into Esri multipatch and written into a geodatabase. The resulting data was then loaded as layer to be used for analysis in GIS.
Fig. 3: BIM to GIS workflow with Esri Data Interoperability Extension
Fig. 4: Example of BIM to GIS data migration for a bridge structure
Figure 5 depicts a planned freeway A99 bridge incorporated into the area’s 2D and 3D GIS database in order to link the structure with geospatial environmental and landscape planning data, and to make the necessary analyses, assessments, decisions and optimizations.
Fig. 5: Integration of Autobahn A99 BIM data (circled bridge) into the 3D GIS and environmental planning data model
Environmental Analyses and Assessments
The integrated BIM and GIS dataset were used for two environmental analyses. Firstly, a building impact analysis was performed to assess environmental impacts. Secondly, the analysis was carried out to determine land consumption by the construction site. A vegetation clearcutting schedule validation and analysis was also carried out to prevent costly delays and to identify potential problem sites caused by protected flora and fauna. The lines perpendicular to the freeway show the split generated by the route event layer split technique.
Fig. 6: A99 bride construction site impact analysis using planning, environmental and base data in a GIS environment
Fig. 7: A99 bridge site impact analysis and necessary compensations for the Landscape Management Plan (LBP) – Temporal impacts vs. untouched areas (top); permanent land use vs. impact compensation (bottom)
Fig. 8: Identification of potential conflicts between the BIM schedule for vegetation clear- cutting and protected flora and fauna
Discussion and Conclusions
The A99 expansion pilot project is a practical demonstration of how GIS is an indispensable component of the BIM process and the integration of both technologies resulted in an excellent exchange of information among different stakeholders to execute the project effectively.
According to German planning legislation and requirements, every stage of the engineering process (from initial project drafts to plans, execution, management, and rebuilding) has to be accompanied by environmental and landscape planning procedures. Figure 9 depicts how the interdisciplinary cooperation among engineers and environmental / landscape professionals were necessary for a successful construction process within the BIM lifecycle.
The A99 expansion pilot project highlighted following key advantages of the integration of BIM and GIS in the planning practice:
- Spatial Intelligence: Geographical analysis of a project prior to its implementation is made easy using GIS data to understand and foresee its affects in the longer run.
- Professional Data Management: Large datasets can be professionally managed in a BIM and GIS integrated system which allows multiple users at a time to engage with its operations.
- Network & Logistics: GIS supplies important components and spatial models for the transport of materials, supply and disposal, mobility of people,
- Modelling & Prediction: GIS provides important planning information, not only for environmental impact assessments, but also modelling methods for reviewing legally binding specifications, e. g., noise limits, water quality, protection areas etc. GIS can also provide real-time sensor information of a project and its surrounding
- Monitoring: GIS continuously provides up-to-date monitoring data on construction progress and environmental impacts (noise, air pollution, ).
- Visualization & Web: GIS tools like 2D maps and plans, 3D web scenes, models and dashboards help to communicate efficiently throughout the planning process between the planners, other stakeholders, and, above all, the non-specialized
The experiences of A99 project proposed that a mutual data set should be created to meet requirement of both BIM and GIS professionals. Text written attributes of CAD standard data sets must be placed consistently into smart GIS data.