## Vertical curve verification

## Vertical curve verification

(OP)

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

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

## RE: Vertical curve verification

## RE: Vertical curve verification

If the actual longitudinal grade of the road is the concern then see chicopee's answer above.

#

## RE: Vertical curve verification

I need to check only vertical curve requirement. I have attached the requirement that A&E has to satisfy.

Any help?

## RE: Vertical curve verification

## RE: Vertical curve verification

Thanks for pointing out.

## RE: Vertical curve verification

## RE: Vertical curve verification

But a 7.5" chord offset to road surface is pretty clear. This equates to a 50' long vertical curve for a 10% difference in algebraic grade. It has a "k" value of 50/10=5.

The design has k values of 130 and greater, so they are much more gradual.

The sharpest curve has a k value of 130. The offset is 4" over a 200' chord, so is much flatter than the 7.5"/50 criterion.

## RE: Vertical curve verification

Per Chicopee, 7.5"/50x12= 1.25%, according to you grade difference 10%. Is this related? My transporter requirement for vertical curve is 7.5" over 50'.Thanks.

## RE: Vertical curve verification

Also for sag curve the grade difference will be of subtraction of two grades, right?

## RE: Vertical curve verification

## RE: Vertical curve verification

Thanks. Appreciate your help.

## RE: Vertical curve verification

## RE: Vertical curve verification

## RE: Vertical curve verification

Sorry I am not civil engineer and I saw that vertical curve is function of parabolic curve. Is there a formula or method to calculate 7.5" in 50' has grade difference of 10% ?

Appreciate help.

## RE: Vertical curve verification

## RE: Vertical curve verification

## RE: Vertical curve verification

## RE: Vertical curve verification

## RE: Vertical curve verification

25C is the maximum rate of change in slope. (the instantaneous slope at any two locations 6.5 ft apart on a vertical curve must not be more than 1% different.)

## RE: Vertical curve verification

Thank you. Appreciate your help.

## RE: Vertical curve verification

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?

## RE: Vertical curve verification

## RE: Vertical curve verification

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).

## RE: Vertical curve verification

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 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)

## RE: Vertical curve verification

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

## RE: Vertical curve verification

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

## RE: Vertical curve verification

Any help? Is it different than longitudinal slope?

Appreciate any help with terminology.

Thanks

## RE: Vertical curve verification

## RE: Vertical curve verification

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.

## RE: Vertical curve verification

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.

## RE: Vertical curve verification

Appreciate your help.