Curb Layout

[cieg22]

Hey, gang. can anyone point me to guidelines on laying out plain conc. curb in a manner that won't cause cracking - i'm designing sidewalk bumpouts/planters and i'm trying to avoid sharp corners. in some areas though, it's difficult to round everything. i know the guideline is to provide a min. 4" thickness to avoid cracking, but beyond that i'm at a bit of a loss. i'd like to avoid adding reinforcement if possible. btw, this is in pa. i didn't see anything in the penndot standards, but perhaps i overlooked it.

thx.

 

[jgailla]

A curb radius of 2 feet is about the minimum that can be done by machine as far as I know. You should not need any reinforcing in standard concrete curbing.
Cracking can be controlled by using contraction joints spaced about 15 feet apart and at the beginning and ends of curves. You will also need to put in expansion joints about every 50 feet and where the curb abuts sidewalks or other site features. You should probably also use 6" thick curbs.
For some good information on different types of curbing, you can google FDOT Design Standards and look at Florida DOT curbs. It is a big file, but there is a lot of good information in it. I am surprised that PDOT does not have a similar book of design standard details.

 

[cieg22]

Don't get me wrong - PennDOT's standards are terrific. Lots of standard details for curbs, etc. The info I'm seeking isn't typical. The planters are in the sidewalk. they come up to the back of the curb. the entire perrimeter of the planter is also curb, so that there is a point where the "sidewall" meets up with the curb on the street (with an isolation joint there) i'm trying to determine whether or not the sidewall curb can meet the back of the street curb at any less than 90 degrees, without risk of cracking. hope this makes more sense than my last post.

thx.

 

[cvg]

here's a similar design currently being built. Yours sounds a bit trickier though.