Roadway Profile Grade Line
Roadway Profile Grade Line
(OP)
I posted a thread earlier about overlaying a roadway with 2 inches of asphalt. After the survey was performed the existing roadway profile grade line is not smooth...after reviewing the existing profile grade the general slope of the road is -0.20% with variable grade breaks that are a couple of tenths and hundreths on 50 ft intervals. When preparing the proposed profile grade is it worth making the profile smooth or just follow the existing profile grade? If the profile is smoothed out is it going to be a construction headache that's not worth the effort?





RE: Roadway Profile Grade Line
It usually comes down to money, if you have enough funds to include a level-up course this would be even better. Given two oportunities to improve the ride (two courses of ACP) usually allows ruts to be filled, cross-slope to be corrected, much better ride.
Even if you just include enough quantity ($) for leveling up the worst areas of pavement, you should improve the ride substantially.
Without an overall picture of the existing roadway your question is hard to define, generally a 2" overlay should be adequate to imprive the ride.
RE: Roadway Profile Grade Line
RE: Roadway Profile Grade Line
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RE: Roadway Profile Grade Line
I'm not sure I completely understand the issue as you describe it. I have some questions:
1. I'm not clear on what you mean by a -0.2% grade. Is this the longitudinal grade along the road centerline profile? Or something else? Does the negative number just mean that it is falling in elevation in the positive (stationing) direction? Or something else?
2. What exists along the edge of the paved roadway? Is it a ditch, or is there some sort of curb or curb/gutter system, where you have to match the grade?
3. If there is a curb or curb/gutter, what is the typical longitudinal grade along the curb and gutter? (It could be different than the centerline profile grade).
4. What is the typical (or range)percent cross-fall on the pavement from centerline to the edge of pavement?
5. Are you aware of any drainage issues/"bird baths" on the existing road pavement?
These things would be helpful to know. I've done a lot of road design/widenings/retrofits where these issues are critical to making final design decisions. I'll try to help out.