Let me start off by talking about how BIM (Building Information Modeling) and Civil Engineering relate to one another. If your firm is currently coordinating on projects with architects, MEP engineers, and even structural engineers, then you have definitely heard the "buzzword" BIM. While the concept of BIM did come from the building design industry, it can also relate to us as civil engineers in many ways.
Incorporating BIM into civil engineering can be streamlined with the use of AutoCAD Civil 3D, which is dynamic, model centric-based design software. Through the use of BIM and Civil 3D we can now create constructability studies to review our designs before they enter the construction phase. Civil 3D can also streamline the creation of multiple design iterations in which volume and material analysis can be run to ensure that we are doing all that we can to build a more "sustainable" design. Sustainability for civil engineering can mean things such as smart location, stormwater management, and steep slope protection. All of these factors play into our designs in order to create accurate models that can reduce the overall impact on our urban surroundings.
The one area of civil engineering design that can see an immediate benefit from the use of BIM and Civil 3D is transportation. The design tools within Civil 3D are so robust that you not only have the ability to design highways and roadways using traditional civil engineering calculations, but you also have the ability to cycle through multiple design iterations and compare your design alternatives to AASHTO (American Association of State Highway and Traffic Officials) tables for passing sight, headlight distance, and superelevation methods.
Within Civil 3D 2009 you have the added ability to create "custom" design check criteria, which enables you to verify that your horizontal alignment design meets the minimum standards required by your local agency. When you use the criteria-based design feature, you have the ability to select a design criteria file that can be project specific, from which you can specify the superelevation attainment method and minimum radius and transition (spiral) length tables. When you lay out the alignment, the appropriate minimum values specified in the design criteria file that has been customized by your firm are displayed on the command line. You can chose to either accept the default minimum value for a given entity or enter a new value.
Another area where BIM has a direct correlation to the civil engineering community is general contractors and construction firms finding that they can significantly reduce construction delays and cost overruns by creating a "virtual build" before beginning physical construction. This allows the contractor to evaluate the project for constructability. Civil 3D can also be used by these firms to take their 2D construction documents from the various design disciplines and turn them into 3D BIM models. We can then help to bring these models together for electronic clash detection and conflict resolution through the use of Navisworks. In addition, the piping tools within Civil 3D have a 2D and 3D Interference Checking mechanism for water, storm drain, sewer, or any other pipe networks that are part of your design model. This allows RFIs and change orders to be issued prior to physical construction—before they become issues in the field and delay the project.
By using phasing, we can develop the BIM models in conjunction with the project timelines to increase communication and gain a better understanding of the construction process for project stakeholders. Construction sequences can be simulated for quick and effective decision making by the contractor, design team, and project owner. Schedule sequences can be stepped through to show the project at particular moments in time and linked to the actual project construction schedule. In addition, the information from a building information model can be used to perform quantity take-offs for tighter budgeting and cost estimation.
In conclusion, through the use of AutoCAD Civil 3D, civil engineers can design models that provide multiple design alternatives to their clients, use design visualization tools to better communicate the design intent, run cut/fill and material volume calculations with ease, run conflict detection checks on pipe systems, and minimize our impact on the urban sprawl. All of these factors combine to incorporate BIM into the civil engineering community and ultimately gives us the ability to reduce errors and omissions, deliver a higher quality product to our clients, reduce costs, and increase project profitability.
For additional information on BIM and how you can incorporate these concepts into future projects, please visit: http://www.uscadbim.com/
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Melanie Santer is the Civil Engineering Technical Manager for U.S. CAD managing the Civil Engineering division and technical staff. Prior to joining the reseller channel, she worked as a field surveyor, an inside survey technician, and supervisor. Ms. Santer has more than five years of industry experience as a civil drafter and a civil designer on large commercial and industrial projects throughout California. She has been a part-time professor at California Polytechnic State University, a featured instructor at Autodesk University several times, and in 2006 earned Autodesk Instructor of the Year for the Americas. She regularly provides training, customization, and support for AutoCAD, Autodesk Land Desktop, and AutoCAD Civil 3D and has been involved with more than 40 Civil 3D implementations throughout the Western US.
