Discover how to create a unique assembly with a baseline not at the center of the roadway, specifically used to create a cul-de-sac at the end of alignments. Learn how to carefully construct this assembly using Civil 3D, ensuring precise placement of elements like lanes, curbs, sidewalks, and grading.
Key Insights
- The article provides a step-by-step guide on creating a non-mirrored assembly with the baseline not at the center line of the roadway, used for creating a cul-de-sac at the end of alignments. This requires careful planning and understanding of how the corridor will be built and where different elements need to go.
- Civil 3D serves as a valuable tool in this process, allowing for precise placement of elements such as lanes, curbs, sidewalks, and grading. The assembly is constructed in such a way that the lane is on the left-hand side (towards the center) while curb, sidewalk, and grading are on the right-hand side (towards the outside).
- Despite occasional issues with Civil 3D not allowing the selection of the baseline, there are simple troubleshooting steps to overcome this issue and proceed with the assembly creation process. All parameters must be set accurately to ensure correct assembly construction and alignment with the main roadway.
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In this video, we're going to create another assembly, but this time we're going to be creating assembly that has the baseline not at the center line of the roadway. This will be a non-mirrored assembly that we're going to be using to create a cul-de-sac at the end of our alignments.
So in order to do that, first, we're going to go ahead and drop down assemblies and select create assembly. So from here, I'm going to go ahead and name this one end because I'm going to be using those end alignments that we created in the previous videos. I'm not going to write in a description.
I'm going to go ahead and choose my assembly type of other. I'm going to choose an assembly style, a basic code set style of all codes and an assembly layer as was selected by Civil 3D. I'm going to go ahead and click okay.
And because this assembly is going to be associated with those two end alignments, I'm going to go ahead and zoom in here where I have my two end profiles. I'm going to select somewhere off to the right and in the middle. So Civil 3D has now zoomed me in.
I'm going to go ahead and go to my tool palette. I'm going to start working with this. Now, one thing to be absolutely certain of is about how you're going to actually build this cross section.
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So what we're going to go ahead and do is we're going to look at this. I know that this assembly at the beginning and end points is sitting 17 feet off of the center line. And if you remember from the previous assembly that we created, our lane width was 17 feet.
So what's important to know is about how this corridor is going to be built. When we build this corridor, we're going to place these assemblies along this alignment. And so we need to know how we're going to be constructing that and which side different elements are going to need to go onto.
So as we drive along this alignment, the left-hand side is going to be towards the roadway and the right-hand side is going to be towards where we're grading to a surface. Since I know this is 17 feet and I know my lane width on the assembly for the main alignment is 17 feet, I know that my lane is going to be on the left-hand side. So as I'm driving around, left is towards the center, right is towards the outside.
So my lane is going to be to the left. My curb, sidewalk, and grading is going to be to the right. We're going to go ahead and go back over to that assembly and build it in that manner.
We're going to navigate over here. We're going to go ahead and start on the left side with the single element and then go to the right side. So I'm going to go ahead and go with a basic lane transition because I'm going to want to keep a slope of 2%, but I'm going to want to target my centerline alignment.
So I'm going to go ahead and navigate down here, choose hold grade change offset. I'm going to go ahead and choose side to left. I am going to choose my insertion point as edge of traveled way.
Now, crown point on inside, yes or no. I always have trouble with this one. Instead of going into the help menu, I'm going to go ahead and just leave it as no, and we can change it later if it doesn't work out.
I'm going to leave my default width of 12 because we're going to be using a target. My depth of 0.67 is okay, but my default slope is not negative 2. I don't want it pitching down towards the center. I want it coming up.
So I'm going to choose two and hit ENTER to select that. Now what I'm going to go ahead and do is navigate and select the marker point within my assembly. I'm going to choose the baseline and sometimes civil 3D does this.
It doesn't allow me to select my baseline. All I have to do is just start over again. I'm going to go ahead and click basic lane transition.
I'm going to go ahead and choose left. Uh, I'm going to choose edge of travel the way I'm going to leave. This is no, I'm going to change this to two.
And then I'm going to change this to hold grade change offset. I'm going to go ahead and select. And now my lane is placed.
If for some reason you click and it doesn't work, I have this issue. Sometimes I don't know what causes it, but all I have to do is escape out, choose what I'm going to be working with again, and then place it. So moving on from here, I'm going to go ahead and place a basic curb and gutter.
I'm going to be placing it to the right. I'm going to be placing it at the gutter edge with the width of 1.5 gutter slope of negative six height. I'm going to keep all these parameters the same, just as we had in the other assembly that we created.
I'm going to go ahead and select this marker as the middle and it places my curb. I'm going to go ahead and choose now to place a basic sidewalk. I'm going to leave all the parameters the same because that's what we did with the previous assembly.
And I want to make sure that these widths all match so that we have a matching cul-de-sac with our main alignment. So I'm going to go ahead and make sure that I'm doing it to the right hand side, which I have right marked. So I'm going to go ahead and pick the location for where I would like to place my sidewalk.
Then I'm going to navigate to my basic side slope cut ditch. I'm going to select it. I'm going to go down here and I'm going to change my four slope, bottom width, and back slope to zero, like I've done on all the other assemblies that we've dealt with.
So I'm going to go ahead and choose four, change it to zero, choose two, change it to zero, choose four, change it to zero, and then hit ENTER to accept that zero. I'm going to select the marker point within my assembly here, and then I'm going to hit escape to get out of this command, and I'm going to close my tool palette. Now I have an assembly that will have my lane to the left, curb, sidewalk, and grading to the right.
I'm going to go ahead and zoom out, center this up, save, and I'll meet you in the next video.
