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Superelevation Transition Length Formula

16 REPLIES 16
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Message 1 of 17
onsionsi1
8328 Views, 16 Replies

Superelevation Transition Length Formula

Hello There,

 

I would like to ask if i can apply Superelevation Transition Length Formula for length of runoff and runout from AASHTO

{Lr=(w*ed*n*bw)/maximum relative gradient}, {Lt=(enc/ed)*Lr} in XML file (in Civil 3D).

Beacause i tried many times to apply this formula but it didn't success with me.

 

I will be very appreciate for help and advice.

 

Thank you.

Please do not forget approve as solutions and Points
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16 REPLIES 16
Message 2 of 17
gjrcmb
in reply to: onsionsi1

I have not tried defining the formulas for superelevation.  But based on the following two resources I found, it seems that you need to define the superelevation using the variables as defined by Autodesk for AutoCAD Civil 3D.

See Superelevation Variables and Formulas

Also it appears that while you can change the formulas in the XML file or perferably a copy of the XML file, that it probably makes more sense editing them through the Design Criteria Editor.

See Rule-Based Road Design using AutoCAD Civil and AutoCAD Civil 3D

 

Not sure if you had already looked at those resources, but if not, maybe that helps.

Message 3 of 17
onsionsi1
in reply to: onsionsi1

So, i got it we can modify this formula from 

tLength="{v}^3/(46.656*{q}*{r})"

to the following formula

tLength="({w}*{e})/{q}"

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Message 4 of 17
onsionsi1
in reply to: onsionsi1

But one more thing,

I want to calculate the superelevation rate from this equation eRate="({v}^2/(127*{r}))-0.12" instead of this one 

eRate="{v}^2/(2.82528*{r})"

But actually it didn't success with me and return me the minimum eRate

 

So, is there any advice for this issue.

 

Thank you.

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to Remember Please Accept as Solution and Kudos Please
Message 5 of 17
gjrcmb
in reply to: onsionsi1

Are you changing the eRate formula in the Design Criteria Editor?  See attached Editor image.  Note make sure Make File Read Only box is unchecked.

Message 6 of 17
mostafa.amoree
in reply to: onsionsi1

good question .... just like me
Message 7 of 17
GZE
Advocate
in reply to: onsionsi1

Hi am facing the same problem i cant get this formula to work, did you find solution for this?
Humphrey GZE
Civil 3D 2013 64bit SP1
Elitebook 8540w
Core i7 2.8GHz, 8Gig RAM
NVIDIA Quadro FX880
160Gb SSD
Message 8 of 17
onsionsi1
in reply to: GZE

No, in fact i changed the formula in XML files.

GZE what the formula you want?

Let me know and i will try to fix it.

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Message 9 of 17
GZE
Advocate
in reply to: onsionsi1

i want to use this formula    "({v}^2/(127*{r}))-(0.19-({v}/1600))" to calculate "e", When I change it i just get the minimum "e" value

Humphrey GZE
Civil 3D 2013 64bit SP1
Elitebook 8540w
Core i7 2.8GHz, 8Gig RAM
NVIDIA Quadro FX880
160Gb SSD
Message 10 of 17
bpoleuca
in reply to: onsionsi1

Hello,

please explaine how you change the XML file.

I want to make some changes in my country kit.

Thanks in advance.

Message 11 of 17
onsionsi1
in reply to: bpoleuca

Superelevation.JPG

As you can see above image you can modify the equation as you want.

GZE, which Civil 3D version do you use?

 

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Message 12 of 17
joantopo
in reply to: onsionsi1

Hi.

I am interested in this topic.

 

I did a plugin to calculate properly the transition lengths , this way, this plugin added new "manual superelevation critical stations" in the properly station.

 

I have to say that this is for the Design criteria for Spain where the "transition lengths" are a little bit special.

 

To calculate the "transition length", there are a first condition: the first 40 meters on the spiral subentity, it must reach +2%, but I don´t know if we can get the Spiral length using an XML file. Do you know it?

And I don´t know if I can apply a conditional in the formula.

 

Thanks in advance.

 

 

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Message 13 of 17
GZE
Advocate
in reply to: onsionsi1

Am using 2016, i know how to change the formula using modify tool my problem is i dont get expected results on the calculation of "e" all i get is 3% for all input radius, in my region we restrict 3% superevation within 40m to facilitate drainage so i usually adjust superelevaton view
Humphrey GZE
Civil 3D 2013 64bit SP1
Elitebook 8540w
Core i7 2.8GHz, 8Gig RAM
NVIDIA Quadro FX880
160Gb SSD
Message 14 of 17
onsionsi1
in reply to: joantopo

Hi Joantopo, Sorry for late. I don't understand you probably but in our project we draw the Spiral in alignment that carried the total transition length. So, if you send an image to explain your issue it will better to understand your issue.
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Message 15 of 17
onsionsi1
in reply to: GZE

Hi GZE, Sorry for late also. Yes i tried many times to fix this issue but it appeared there is a bug in Civil 3D, i don't know if someone can raise this problem to Autodesk and explain this bug. In fact i modified the speed and SE tables and finally it worked correctly. Like if you have many speeds 40,50,60,80,100,120 then you can to the table and modified the SE for each speed and eventually save this table so you can you use next time in other project. Hope it help you.
Please do not forget approve as solutions and Points
to Remember Please Accept as Solution and Kudos Please
Message 16 of 17
r456r
in reply to: onsionsi1

Hi,

 

 I tired using your instructions regarding change in formula of transition length. I'm using it but its saying that formula is inavil when I try to use superelevation wizard. Your input in this matter will be hihgly appreciated.

 

RegardsUntitled.jpg

Message 17 of 17
kalusalingam33
in reply to: onsionsi1

Hi dude's,
I need a help to resolve the design check violation during Calculation of superelevation.I tried to resolve the design check and every time I got the violation Statement as "Rate of change of cross slope is larger than 6% per 30 meter" kindly any one Could give me the best solution.This violation is necessary resolve or not? Give me the brife explain about this violation.

Thank you

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