This article provides an in-depth guide on creating intersections in Civil 3D. It includes specific instructions on settings and parameters such as intersection corridor type, offset parameters, curb return parameters, and corridor regions.
Key Insights
- The article outlines the process of creating intersections in Civil 3D, starting with the selection of intersection points and naming the intersection.
- It discusses various settings and parameters such as choosing the intersection corridor type (either all crowns maintained or primary road crown maintained), setting offset parameters for primary and secondary road, and defining curb return parameters.
- The walkthrough also explains steps such as creating corridors in the intersection area and selecting a surface to daylight to.
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In this video, we're going to go ahead and create some intersections now that we've prepared our corridors to accept them. So to do that, we're going to go ahead and drop down into this Intersections dropdown, select Create Intersections, and then Civil 3D is going to prompt us to select our intersection point.
I'm going to go ahead and start by creating the first intersection, which is going to be our Highway and our Dev Main alignment. So I'm going to go ahead and zoom in to around where our intersection is. I'm going to go ahead and hover over where that intersection might be, and I'm going to try and snap using this X snap right here for intersection.
I'm going to click. Now, sometimes Civil 3D doesn't quite grab the right one, so I'm going to click around in here and try and find that intersection.
And so I've now clicked around. Civil 3D did find the intersection. So I had to click a little bit up above here, but ultimately Civil 3D did find this intersection.
Sometimes it has a little bit of a hard time. But moving on from here, I'm going to go ahead and write in the name for my intersection, which will be Intersection Highway-Dev. And then I'm not going to write in a description.
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I'm going to leave my intersection marker as the marker style for this. I'm going to leave the layer the same as what Civil 3D has preselected. I'm also going to save this as a Basic intersection label style.
We can add labels or change the label styles later. Same thing with this marker style—we can modify that marker style if we need to.
Now, what we need to do is decide how we're going to be handling the intersection corridor type. When you choose this, Civil 3D will automatically update this little image down here. So you're either going to do All Crowns Maintained, which is like a standard intersection, or you're going to go ahead and do a Primary Road Crown Maintained.
Now, for this intersection, I want to go ahead and do Primary Road Crown Maintained because we are doing an intersection with a highway where we don't want to mess with the cross slopes of the highway, and then we have a secondary road coming in. When we do our Dev Branch to Dev Main alignment intersection, we'll do the All Crowns Maintained. So I'm going to go ahead and select Primary Road Crown Maintained.
I'm going to go ahead and click Next. So inside of here, what we're seeing here is Priority One: Existing Highway, Priority Two: Dev Main. It's giving us station equations for the intersections.
It's giving us the profiles associated with those alignments. So from here, we're going to go ahead and look at our offset parameters for our alignments. So I'm going to go ahead and go in here and choose Offset Parameters.
So as we can see here, we're doing primary road offset parameters and secondary road offset parameters. So what I'm going to go ahead and do is I'm going to look at this and say Left offset alignment definitions. I'm going to change my offset value to zero because on the left-hand side, we're not modifying the roadway.
So I don't want to include any information on the left-hand side. Then we have the right-hand side. So on the right-hand side, we know that the road is 30 feet wide.
So I'm going to go ahead and type in 30 for the offset value. And then we'll do some modifications to the intersection after Civil 3D creates that intersection. So I'm going to go ahead and click OK for that.
I'm going to go to my offset values for my secondary road. And I know that the offset values for that are 17 because that's the lane widths that we selected when we created our original assemblies. So then I'm going to go ahead and click OK.
So moving on from here, I'm going to go to the Curb Return Parameters. When you have selected an intersection, we're not doing information on the left-hand side and our alignment doesn't cross through. So Civil 3D knows that we only have two curb returns that we're going to be creating, the Southeast Quadrant and the Southwest Quadrant.
So I'm going to go ahead and go with the Southeast Quadrant first. And then it's giving us an option to do a widened turn lane for incoming road or a widened turn lane for outgoing road. We've already created this widening, so we don't need to check these to create them.
So what we're going to go ahead and do is we're going to choose the curb return type and the radius. I'm okay with a Circular Fillet, but I want to change my radius to 10 feet. So I'm going to go ahead and highlight 25, change it to 10.
Civil 3D is not letting me change it to 10. I'm going to try it one more time—10. There we go. Now I'm going to go ahead and go to my Southwest Quadrant, do the same thing, change 25 to 10.
And then I'm going to go ahead and click OK. So moving on from there, we have our Lane Slope Parameters and our Curb Return Profile Parameters. I don't need to change these or modify them.
Civil 3D is going to create these for me utilizing what's in these profiles here. And since you can see the defaults are all 2%, I'm okay with that because all of my assemblies that I created were at 2%. So I don't need to modify that.
And then I don't want to modify anything related to the Curb Return Profiles. I don't have any profiles I want to target. So I'm going to go ahead and leave this information as is.
But if you wanted to change it, you have your Southeast and Southwest Quadrant information that you can change. I'm going to go ahead and click OK. And then I am going to move on to the next section, which is the Corridor Regions.
I'm going to go ahead and click Next. And then inside of here, you have the options for Create Corridors in the Intersection Area. Yes, we want to do that.
We want to create them as new corridors. We don't want to add them to an existing corridor. We want to select a surface to daylight to, which is the CIV202.
