Autodesk is pushing the concept of Building Information Modeling (BIM) into areas outside of simply buildings. The company describes BIM as an integrated process that coordinates reliable information about a project through all phases of design and construction, and they see increasing opportunity for the application of the BIM approach in the civil engineering space
“BIM has a firm foundation in architecture and construction, but the principles of BIM apply to everything that’s built, including roads and highways,” said Adam Strafaci, senior industry marketing manager, civil engineering at Autodesk. “A BIM process allows civil engineers to not only create designs, but more easily predict the performance of projects before they’re built, and to optimize the designs through visualization, analysis and simulation.”
The virtual environment within the software allows the incorporation of design intelligence into the process, with returns in terms of time and materials savings, as well as enhanced road safety. When designing a roadway there are a number of safety considerations, including the road slope, turning radius and signal location that are tied to roadway speed limitations.
Traditionally an engineer would use two-dimensional drawings and formulas to determine if a roadway design met safety standards. With Autodesk’s AutoCAD Civil 3D software, the engineer can turn to criteria-based design to automate that process and check the design against criteria as they are designing. The software includes many different design criteria, including the safety criteria from the American Association of State Highway and Transportation Officials (AASHTO) used widely in the United States.
Visualization and simulation enhance the rules-based design view to incorporate elements related to how the roadway interacts with the environment around it.
|The above visualization within the Rapid Road Safety Analyzer from RDV Systems leverages the information model in AutoCAD Civil 3D, Autodesk’s civil engineering software built for BIM. Here the visualization helps the civil engineer identify whether the road geometry meets critical safety parameters. Image provided by RDV Systems|
“The simulation of driving a roadway alerts an engineer to elements that may not have come up in the mathematical criteria-based approach,” said Strafaci. “When you’re working in the visual environment you can quickly get a more complete view of the project area, to take into account visual obstructions from buildings, barriers, vegetation and surrounding terrain.”
The building information modeling environment also automates the creation of construction documentation, which frees up engineers to spend more time taking a look at alternative design scenarios and to engage feedback from collaborators in the design process.
“The model itself becomes a tool for design collaboration,” added Kevin Stewart, senior product manager for Civil Transportation at Autodesk. “The model can be used in public hearings and design reviews to get input from construction, operations and maintenance people. It’s also used to factor in constructability issues for cost reductions, and to eliminate any design errors before it’s built.”
The traditional workflow of a roadway has been a very manual approach. One group typically conducted the preliminary design, and then another group did the detailed design. During the detailed design, different groups involved in different criteria, such as drainage, constructability and safety, reviewed the design. Any alteration by any of these specialty groups would have to weave back into the whole design process.
“There’s a balancing act going on here, and the connectivity between groups through a central model makes design iterations something that is cost effective, and not cost prohibitive,” Stewart stated. “When you’re using traditional drawings you’re limited in the number of changes that you can make, and it’s hard to get a handle on the impact of a change in one area on other factors. What might improve one aspect may cost you in another aspect, and analyzing various factors and deciding what trade offs are acceptable are a key part of the design process, which is greatly improved by the BIM approach.”
While the idea of BIM for architecture and construction has taken hold to the point that it is being called a revolution, the use of BIM for civil engineering is still in its infancy. Autodesk announced in June of this year that the Wisconsin DOT is implementing AutoCAD Civil 3D, and they added Florida DOT to their Civil 3D client list this month. According to Autodesk, the benefits of the BIM approach were a compelling factor in these software licensing deals. It's only a matter of time until BIM leads the wish lists of civil engineers for a wide variety of applications.