When building sidewalks and parking lots, creating accessible curb cuts can be done directly on the floor elements using the Revit shape editing tools.
- [Instructor] Whenever you're working on your site plan for your project, and you have sidewalks or parking lot areas, then chances are you're probably going to need some accessible curb cuts. So in this video I'd like to share with you one way that you can build an accessible curb cut, and then in next week's tip we're going to take a look at a second technique. So, to start off in this one we're going to use the simple floor elements that we have right here, that represent a sidewalk and then a little adjacent road. And we're going to create something like this, what you see over here at this little curb cut area.
So I'm going to go to the level one floor plan to get started. And the approach that we're going to take in this week's tip is to kind of build it in place. In situ directly on the floor slab element. The approach we're going to look at next time is the one that you saw in the 3D view that I just closed. And that's actually a loaded family. So we'll talk about how to create a family that will achieve this same thing But let's start with the approach of building it directly onto the floor element. Now, what you'll see here is I've got some reference planes already here to get us started.
Now those reference planes represent some of the key dimensions that we'll need to build this curb cut. Now I've gotten these directly from the U.S. Department of Transportation, Federal High Administration website. And if we scroll down towards the bottom, there's a nice little diagram right here. And it shows us that we have a sidewalk area with a required minimum five feet, is what they're suggesting there. A buffer area that the curb cut will be cut into with the slope in that area for the ramped portion of it being at a maximum of 8.33%, and then two flared sides with a maximum 10% slope for those.
So that's what each of these reference planes is for. So here I'm representing the buffer area. This is the sidewalk area. You can see that I've got a five foot dimension here that I just simply locked together. So that just allows me to move one of these reference planes, and have them stay attached to one another to maintain that sidewalk. I've got the right flare here, the left flare here. So what I need to do is figure out this dimension, this one, and this one, so that I can create the points that are required to build my curb cut.
So let's start with the ramp itself. So I want to locate this reference plane at the correct location to give me an 8.33 slope. So how do we do that. Well standard curb height, in the United States anyway, is six inches. So that's what I've built here. This floor element is six inches above the road area beneath it. So it turns out that just like you can in Excel, in Revit you can actually put formulas directly in your temporary dimensions. So the way you do it is, like Excel, you just type the equal sign.
And so what that's going to do is allow you to do the calculation right in the temporary dimension. Now of course, if you prefer, you can pull out your calculator and do the calculation off to the side. Then just plug in the actual number. But this is a fairly easy calculation, so I thought we'd do it right here in the dimension. So I'm going to do 100 divided by 8.333. And then I'll put that in parentheses, both left and right parentheses. Now what that is, is just another way of saying 8.33%. That's like saying 8.33 one hundredths, which is the same thing.
So once I've got that number, I need to multiple that by the heighth of my curb, which we said was six inches. Now this file is in feet, so I can put in six inches by just doing .5, half a foot. And when I press enter, it will do the math for me, and make that distance six feet. Now if you think about it, you can kind of do a little mental check and verify that that's correct. Because 8.33% is the same as one in 12. So that slope is one inch rise over 12 inches of run.
Or one foot rise over 12 feet of run. So if we had 12 feet of run, we would go up one foot. But we're only going up half a foot. So when you go up half a foot, you would only go up half of that run, six feet. So it checks out, right? So that's how you can kind of do a quick little check and make sure that that's the correct value. So we'll do it again here. And this one's a little easier because 100 divided by 10% slope, well we could easily do that math in our head. But I'm just going to go ahead and put the formula in a second time.
Just so you see it a second time. So it's 100 divided by 12 in parentheses, times half a foot, and this time the value comes out to be five. So now I'll just take that value and apply it on the other side, because those two need to be the same. So now that I've got these reference planes in the correct location, I can move on to creating the cut in the slab itself. And we're going to do that using the shape editing tools. Now shape editing tools allow you to place points on the surface of the slab, and then move those points in the Z direction.
Now it's a little difficult to get these points placed precisely, which is why I went to the trouble of building these reference planes. If you build the reference planes, when you're placing these points, you can snap directly to them. And that's really the only way that you're going to get it to all line up correctly, and be the correct size and shape. Now we could use the Add Point tool. I like the Add Split Line tool, but they'll essentially do the same thing for you. So I'm going to go with Add Split Line, and I'll start right here. And you see how it finds the intersection of those reference planes? So we can place it very precisely, doing this.
If you don't have the reference planes, it's all going to be kind of eyeballed. So I'm going to go ahead and create the tapered sides here, and then two vertical lines here and here for the sides of the ramp. Now once you've done that, the final step is to just simply move the Z heights of those portions you've defined. Now you do that with this Modify Sub Element tool. Now the way this works is, you can select any of the sub-elements, individual points, lines, any of the lines that we've drawn, and even the green outline that was already there initially.
Now notice that we get the green outline separated into sections now, including these small points at those joints. So if I just click this middle section right here. I can move it down, and it will taper the two sides for me automatically. So one simple modification is all that's required here. Let's move this down six inches, negative six. Or you could do negative .5. But if you do six, make sure you put the inch symbol. And when I enter that, it's lowered that edge down six inches, and all the other points will adjust accordingly.
And the shape of the slab will now slope. And the easiest way to see that is to reopen the 3D and there it is, right. So just like that we're able to create sort of an in place or in situ curb cut directly on the surface of the floor element. Now this works great if you just have one or two of these to do. But if you're going to have lots of these, you know you're doing a very large parking garage and you have these all over the place, this might start to get a little tedious because for each one you're going to need those reference planes, you're going to need to position them correctly, snap all your points, then lower the points.
So for cases where you have lots of them, you might choose to use this technique instead, where you actually create a loadable family and use that loadable family to cut the slab instead of doing it with the shape editing points. And that will be the subject of next week's video.
NOTE: The exercise files for this course can only be opened in the most recent version of Revit (Revit 2017).
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