Vertical curve verification 1

[trivedi123]

I have transporter requirement for vertical curve is 7.5" in 50'.
I have A&E report showing profile of vertical . I need help to verify requirement.
Attached is the profile.
Any help will be appreciated.
Thanks

 

[trivedi123]

TerryScan,
Thank you. Appreciate your help.

 

[trivedi123]

TerryScan,
1. 7% in Fig. 58.1 is clear.
2. Note 25c, is applicable to Transition slope , that could be horizontal transition and kind of levelness requirement, Am I correct? For vertical curve it is grade change and note 25G will apply, right? So 25C also apply to vertical curve along with 25G?

 

[trivedi123]

note 25f

 

[TerryScan]

Road length is length whether it is vertical or horizontal.

Slope is vertical (it is NOT talking about a horizontal transition). But yes, this would appear tho apply whether it was a vertical curve or some other miscellaneous grade change (typically a vertical transition takes the form of some kind of vertical curve). The bottom line for 25C is that two points 6.2 feet apart along the road LENGTH should not be more than 1% different in slope.

25G is about longitudinal surface smoothness. It is NOT about slope transitions.

As to which item applies - "shall meet the following specifications, in any combination" (they all apply).

 

[TerryScan]

trivedi: are we still talking just about the profile in your first post?

To take the 450' Vertical Curve as an example:

I computed the surface for a 50 ft. segment:
Station ____ Elev. _______ Slope ______ Description
605975.0 ___ 4393.71 ____ 2.4753% ____ (25 ft. before)
606000.0 ___ 4394.35 ____ 2.4753% ____ near PVI
606025.0 ___ 4395.01 ____ 2.7236% ____ (25 ft. after...for total of 50 ft.)

25A - yes less than 7%
25B - (no cross slope information provided
25C - slope transitions are less than 0.25% in 50 ft. (so they are certainly less than 1% in 6.2 ft)
25D - (information not provided)
25E - (information not provided)
25F - Fig 58:

calculate the slope of the chord from sta 605975-606025: (4395.01-4393.71)/50=2.6%
calculate the elevation of the chord @606000: 25*2.6%+4393.71= 4394.36
difference from surface elevation: 4394.36-4394.35=0.01 ft = 0.12" (less than 7.5"- OK)
(don't see units for 7.5 but you said it is inches)​

25G - need to check with 10 ft. straight edge

 

[trivedi123]

TerrySan,
I really appreciate all information. I am not a civil guy and I am trying to verify somebody's design against requirement. Is there a software to calculate the slope or use formulas?
Thank you

 

[TerryScan]

There is all sorts of civil software for road design. If you Google search for vertical curve calculations you may find some downloadable spreadsheets as well.

Regardless, you should familiarize yourself with the calculations (Google search or Civil texts).

 

[trivedi123]

My requirement 25C above is for slope transition. What is "( slope transition"? Where and how do I verify this requirement? It is at road intersecting each other or road changing direction or changing width. from two lanes to one?
Any help? Is it different than longitudinal slope?
Appreciate any help with terminology.
Thanks

 

[TerryScan]

Slope transition would be rate of change in slope. I tried to answer that in May 2 posts above. What don't you understand?

 

[trivedi123]

Hi TerryScan,
Sorry for my ignorance. I am trying to test this requirement
The requirement Is: "slope transitions are not to exceed 1% in 6.2' in road length in the direction of transporter travel" .
I have longitudinal slope 7%, Transverse slope of 2 1/2%. Is this requirement applicable to these slopes transition in the direction of travel? I read in WDOT that this transition in plan view with road with crown meets bridge with no crown. I am trying to understand the example where this requirement applicable?
Sometime obvious thing to expert may not be easy for learner. Again sorry for my ignorance and appreciate your help.

 

[TerryScan]

I would interpret the plain reading of the requirement to mean than when one wants to transition a longitudinal slope, it cannot exceed the tolerance stated (it does say "in the direction of facility transporter travel").

So, for the profile you provided in your first post, there is a grade change from 1.36% to 3.84% (more than 1% total). 25C says one must transition from the 1.36% to the 3.84% in such a way that the change is not more than 1% in a distance of 6.2 ft in the direction of travel. The vertical curve at Sta 66060+00.78 achieves this. I provided some this information in my May 2 post. One would need to do the vertical curve calculations to verify this yourself. I used Civil software and CAD to computes this. You would likely need to do the same or to hire someone that can do this for you.

 

[trivedi123]

Thank you TerryScan.
Appreciate your help.