Roadway Design in Civil 3D: Roadway Corridors

The features of Civil 3D are needed for the competition for a full design of the roadways. Every technician and civil engineer should have the capability to create 3D corridors, make residential road designs, and finish road surfaces with the help of Civil 3D software. Before the development of the Civil design software, engineers have to make roadway designs by hand. After inventing software like Civil 3D, the design time of civil engineers has been reduced. The Civil 3D software components are linked with each other. This connection allows the designers to make changes in the roadway corridor design process which are easy as well as less time-consuming. It is ensured that the creation of the roadway corridors is done in a proper way by using this Civil 3D software.

Roadway design with Civil 3D

Horizontal Alignment, Vertical Alignment, and Cross Section are the main three basic components that are needed to design roadway corridors in Civil 3D software. Let’s discuss how these design components act within the designs in Civil 3D:

Horizontal Alignment

Two basic components are present in the horizontal alignment which are circular curves and tangents. Several conditions should have considered white making the horizontal alignment. The jurisdictional requirements of the designs should have to be double-checked by the engineers which helps to ensure that the alignment is compliant. The alignment of the roadway corridors should avoid the slopes which may hamper the construction procedures and the alignment should also have to follow the existing terrain. The horizontal alignment should also have to allow for the configuration of lots that need to be met. After designing the horizontal alignments, the engineers can design the vertical alignment of the roadway corridors.

Vertical Alignment

Vertical alignment is called a profile in Civil 3D software. This is the centerline of the roadway design. This alignment consists of tangents and curves and can be viewed from a profile view. The vertical alignment curves are parabolic curves that differ from the horizontal alignment curves. In vertical alignment, it is also important to align with the existing terrain as closely as possible along with the alignment. This helps to reduce the amount of earthwork. There should be a minimum slope of the roadway while designing the vertical alignment.

Cross Section

Cross Section is called an assembly in Civil 3D. Cross Section consists of several subassemblies which are connected to each other to create the full Cross Section. There are various types of subassemblies which include road lanes, shoulders, tie-in grades, sidewalks, curbs and gutters, and others. Numerous different assemblies need to be created as most of the roadways do not have the same Cross Section. The corridor tools present in Civil 3D help to allow the engineers to specify the different assemblies to build the different sections of the roadway. After creating the assemblies, the corridors of the roadways can be built. These corridor modeling tools in Civil 3D are very useful as these tools can be used by the designers anytime as per their needs to design the roadways. To get a smooth corridor design process, designers need to set the corridors at the start of the roadway design procedure.

There are some common workflows that are required to create roadway corridor models:

Flexibility enhancement in corridor modeling

Numerous workflows are present to create corridor models in the Civil 3D software. Various corridor types can be chosen by the designers. These parameters of corridor modeling can be imported from the Civil 3D library or from a custom file. The name of the corridor model, the baseline alignment, required assemblies, and roadway profiles can be specified by the designers on the basis of their usage. All of these criteria regarding the corridor modeling process can be modified by designers later if modification is required. To set the frequency of sections in the corridor parameters, designers need to apply the “by curvature” option in the frequency menu. This option is used to model the roadway corridors more accurately and helps to avoid the segmented look of the corridor models in the tighter areas.

Inspection of the fine-tuned corridors

Designers can inspect the corridor models in the Section editor thus getting the right results in corridor modeling. This helps to get the multiple critical perspectives by designers to detect conflicts regarding corridor models and fix those conflicts. Designers can turn off the target surfaces while dividing the corridors into regions. This feature enables the designers to make more precise adjustments and concentrate on the requirements of the specific regions of the corridors. The overlaps or conflicts in the superelevation calculation can also be identified by the Civil 3D software which enables the designers to adjust the stations on the selected overlaps manually and select “automatically resolve overlap” to resolve the conflict.

Creating complex corridors Intuitively

The feature line or polylines can be used by the designers in Civil 3D which helps to control the median locations. The identification of the lane names is also important to target the corridor model’s specific elements. Control lines can be selected from CAD files by the designers which helps to represent the medians on the sides of the roadway corridors. Polylines can also be created by the designers to fill the gaps in the intersections of the designs. The corridor model can be run by the designers in the Section Editor. This helps to ensure the accuracy of the design process.

To get more details, watch the following video tutorial.

Video Source: Nasser Yari PhD, PE