Curb corner radius 1

[ajk1]

I notice municipal curbs have a corner radius ( I also see that these curbs are sometimes extruded from a continuously moving machine). Does anyone know the amount of this radius so that I can specify it on a typical detail for curbs that I am developing?

 

[r13]

Attach standard detail sheep from the municipal roadway design/construction department, if you work for one.

 

[ajk1]

Thanks...that might be useful, but I don't see any attachment...

 

[DLBridge]

I think retired13 was suggesting that you refer to your local or state DOT for typical curb details.

NYSDOT for example has the following standard sheets: Link

 

[Pinwards]

It depends on the anticipated vehicles that will be using it. Coming out of a parking lot or with primarily passenger vehicles perhaps around 15', on the corner of a normal City block 20 to 25'R, in an industrial park or other high-truck traffic it might be 40'R or larger. Typically each City or State Transportation Department will have their own requirements.

#

 

[CarlB]

Ask the civil engineer on the project. Refer to municipal public works and state DOT for standard specs and details. Site curb and gutter typically are not reinforced, and have radius of about 1/2 inch. Control joints can be spaced 5’-10’, and align with adjacent sidewalk, if any.

 

[ajk1]

I am not very good at phrasing my questions. That is my fault. I should have said that I am an elderly civil (structural) engineer tasked with reviewing our typical details for miscellaneous curbs used for building projects, which include curbs inside and outside a typical building. I can try to obtain the local municipal standards to see what they do, as per your suggestion, but municipal curbs do not include all the conditions that we deal with in a typical building project, which includes curbs not related to sidewalks. However I will follow up on your suggestion.

It depends on the anticipated vehicles that will be using it. Coming out of a parking lot or with primarily passenger vehicles perhaps around 15', on the corner of a normal City block 20 to 25'R, in an industrial park or other high-truck traffic it might be 40'R or larger. Typically each City or State Transportation Department will have their own requirements.

A 15 foot radius on the top corner of a municipal curb seems to me that would result in no discernible curve to the naked eye...or am I not interpreting this correctly

 

[BAretired]

ajk1,
I suspect the 15' radius is in plan view, not in section view.

BA

 

[dhengr]

Ajk1:
Come on, read just a little bit between the lines here. Almost everyone is assuming you mean the curb or turning radius where two streets/pavements intersect, in plan view. If you meant any radiuses, when looking at a cross section through the curb, such as the slightly rounded corner btwn. a vert. surface and a horiz. surface on the curb, that’s another animal. Those shapes and exact sizes are controlled by the pavers formwork system, or by the concrete finisher’s edging tool. While the curb in a bldg. should probably be called out in a sectional detail, or may be controlled by the bull nosed tile you select.

 

[r13]

Even with your latter clarification, I am still puzzled over the radius in question, is it the measurement for the round corners at curb cross section, or the turning radius of roadway. Either case, information can be found from the local/state D.O.T, and/or AASHTO specification/handbook for highway geometric design.

 

[IRstuff]

Perhaps even close to 40 feet:

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[BridgeSmith]

Ok, I'll throw in my $0.02 worth - If you're talking about radius from the face of the curb to the end of the curb (in plan), our bridge (or approach slab) curbs have a radius of 10". Don't know if that's what you're looking for...

Rod Smith, P.E., The artist formerly known as HotRod10

 

[ajk1]

I was referencing the radius of the top corner of a cast-in-place curb, when viewed in section. Sorry about my lack of care in wording my question. When I have something in mind, I don't always appreciate that there is another way of interpreting it. (I am not sure that I am alone in that shortcoming, judging from the number of project specs that I have read in my career that are not clearly written). Again, no excuses and my apologies.


By the way, we no longer use "cents" in Canada.

 

[fel3]

ajk1....

The specified radii for the top face of curb and the top back of curb* vary quite a bit from jurisdiction to jurisdiction. If you do Google searches for "curb detail", "curb and gutter detail", and similar, you will find many examples, including images and links to various agency standard details. When I did this, I saw radii ranging from to 1/2" to 3".

You will also see details for rolled curbs (also known as "mountable curbs"). Rolled curbs have much larger top and bottom radii on the face side because they are meant to be driven over, unlike flat-face curbs. I assume you want flat-face curbs for your projects.

Around here (central California), I typically see agency standards that specify values of 1/2", 3/4", and 1" for the top two radii, with 1/2" and 3/4" being the most common. Sometimes the two radii are different. When they are, the top back of curb radius is always the smaller of the two.

You mentioned curbs inside and outside the building. Curbs outside the building should follow the local public works and/or development standards, which you can get from the local AHJ (Agency Having Jurisdiction. If there is no significant risk of chipping the top "corners" of the curbs inside the building, you might as well use the same cross-section the AHJ requires outside the building. That way you simplify your work and the contractor's work. If the local agency doesn't specify the radii, then you probably get to choose. However, before you make your choice, I suggest talking to a local contractor who builds curbs and curbs and gutters to find our what the local practice is. If they don't have a preference, then it's your judgement call.

For situations where there is a significant risk of chipping the curbs inside the building (e.g. due to fork lift traffic), then I suggest using a radius of at least 1". How large is really up to you.

Fred

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* And, when a gutter is present, the bottom face of curb, also known as the gutter flowline.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[ajk1]

Thank you Fred. Also for the Churchill quote. Much appreciated. I will keep that quote in mind.