Corridor Sidewalk Ramp

[Anonymous]

Does anybody know how to approach modeling a sidewalk ramp at an intersection.  I can't figure out how to do this with a corridor, so I am planning to fill in this area with feature lines.

Here's a couple of images.

[jeff_rivers]

I wish I had some advice for you but I don't.  However I will be doing a similar project soon which has thirty-two ramps.  I would like to see a screenshot or two of your finished ramp model if you don't mind. 

[Joe-Bouza]

One approach is to ignore it and treat it with a detail.

Another approach would be with specific regions and targets in the corridor.

presumably you are using a curb with an urban sidewalk?

if you were to use a curb with a generic link that target the elevation and distance required. In the region of the ped ramp you can edit the corridor at these sections, adjust the curb reveal for the drop curb and you will then have a modeled drop curb and ramp in your sidewalk.

Doing 32 of them may get tedious but it will be dynamic

[Neilw_05]

To me I don't see the curb return as an appropriate alignment to model the ramp. The corridor geometry is too skewed to the ramp geometry to model it accurately. If anything another baseline that aligns with the ramp might give a better solution, but I think it would add too much complexity to be worthwhile to model it with a corridor.

It might be better to leave the curb out of the corridor in the area of the ramp and use gradings to model the ramp. The downside to that approach is that it requires extracting the feature lines from the corridor, and as a consequence, the ramp would not remain dynamic to the corridor.

Hopefully someday we will be have feature lines that remain dynamic to corridors. Until then it will be difficult to get a dynamic solution for this scenario. If someone finds a way to make this work, please post a screen capture or recording.

[Joe-Bouza]

I concur. We also have to keep in mind what we are building, and unless it is for visualizing purposes I stick with my first option, Ignor an let a detail do the dirty work. As designers we need to ensure the field people have the room to accomodate the ADA requirement.

[Anonymous]

You could use feature lines to draw the ramps, then convert to surface if needed.  This would be fairly easy to accomplish by setting your top and bottom elevations to get your ramp, then some infill.

[Anonymous]

I agree with Joe... ignore the ramp grading altogether. There comes a point where the dollar return for the effort is not worth it. No contractor that I have spoken with about this gives a hoot for the contouring of a ramp. They all know the local agency standard details for ramps (or they wouldn't be in business) and build them regardless of contouring. Our agencies don't require it, either, so why do it?

The only situation that I might take time to grade ramps is a site plan where I am using mostly feature lines anyway, and have maybe two or three ramps, in, say, a hotel or bank parking lot situation. But for corridor modeled roadways, I personally don't think it's worth it.

[Anonymous]

The effort isnt really that much if you are much of a user of Civil 3D.  I do however think you are spot on (castle's comments above) with regard to trusting and knowing the contractor/agency knows what they are doing and what ADA requirements they must adhere to.  I was trying to offer a solution to the original question just simply becasue it can be drawn several ways in Civil. 

[Joe-Bouza]

'The effort isnt really that much if you are much of a user of Civil 3D."....

Please turn the light on to the simple way?

[jeff_rivers]

We have had some issues recently with ramp and sidewalk grades exceeding the ADA limits; in some cases the contractor is not fully aware of what the grades need to be, and in other cases the design was not fully checked to be sure all proposed grades are within the required ADA limits. 

We are developing processes to check and verify our proposed grades at ramps and on sidewalks.  I bet there's at least one way in C3D to model them but I haven't spent any time on the problem yet. 

[pdrafter]

"We are developing processes to check and verify our proposed grades at ramps and on sidewalks.  I bet there's at least one way in C3D to model them but I haven't spent any time on the problem yet. 

We have had some issues recently with ramp and sidewalk grades exceeding the ADA limits; in some cases the contractor is not fully aware of what the grades need to be, and in other cases the design was not fully checked to be sure all proposed grades are within the required ADA limits."

We just ran into the same problem and had to cover the repair fee (contractor had to raise the grade). Is there a way to check the proposed slope of ADA ramps with civil 3D?

[Anonymous]

When you say "...grades exceeding the ADA limits," what grades are you referring to? Are you talking about the cross slope of the foot of the ramp at the gutter flowline? The ramp slope going up to the sidewalk?

What sidewalk grades are giving you trouble? Longitudinal? Cross slope?

[Anonymous]

I too am looking for a more dynamic solution to the (re) design of existing city sidewalks.

We have a static design that is complex and its difficult to teach to a new contractor every year or two

We will be doing hundreds of ramps in the future and I would love to find a method to build a "template" or "templates" that can be adjusted either manually or automatically change slopes on ramps and landings depending on certain criteria.

Example; many of our streets (residential) are 60 or 80 ROW with 5' to 7' parkstrips 4' wide sidwalks that are divided into 4' squares. Typically these intersect at the PT of a curb return and have an elevation change in the 0.50' to 2' range. It would be nice to be able to set some parameters that allowed adjustment in those kind of fields...maybe the solution is to design a pedestrian corridor that takes care of it.

I am very new to this design software and could use any pointers anyone has. Thanks

george.ott@slcgov.com

[TonyLeggieri3279]

The simple way has already been mentioned in this post which is "do the detail" separate.  I am not talking about an inset on the plan either.  Remember: model based design!  If you model them upfront, all you need to do is lable on a plan or in a detailed inset.  Still less drafting in the end.  That is the point of Civil 3D.

Model each one with feature lines and grading objects in a grading group.  Create a new surface, paste your corridor first then your grading group second (all ramps can be in one grading group).  Surface 2 overwrites surface 1 in the respective areas.  Use "feature lines from corridor" for your flowline/curb return area to start and it  SHOULD all be dynamic.

The only reason for pasting the 2 into a new surface is you cannot paste into a surface you target and I will assume at some point you may target your corridor surface with your grading groups.

We did this exercise not with sidewalk ramps but with driveway aprons on a residential open-section road with a ditch.  About a 2 mile road with 30' of driveways spaced at "random" intervals.  Feature lines and infills and grading objects tying off at 3:1 for the ditch culvert areas.  Worked great!. 

[Anonymous]

Thank you I figured it was tied to wire frame modeling I'm just not there yet.

Good to know it works with driveways.

Are you able to take that data and input into a second corridor design with lets say NO ditch and negative grades on one side and positive grades on the other side?

[murray-clack]

I found this article, it might help:  http://civil3dguru.blogspot.com/2010/12/autodesk-university-2010-online.html

[TonyLeggieri3279]

Yes you could apply it to any corridor because in the end it will overwrite the surface when pasted.

And Conditional Subassemblies (per that article posted) are AMAZING!!!!!