Permissible Grade given Length Calculator

✖Change in grade is the algebraic sum of two grades in the vertical curve. It is expressed in percentage.ⓘ Change in Grade [N]			+10% -10%
✖Length of Vertical Curve is determined by the permissible rate of change of grade or from centrifugal consideration as appropriate.ⓘ Length of Vertical Curve [L]			+10% -10%

✖Permissible Rate is the maximum allowable rate of change in grade for vertical curves. For railway work 0.1% rate of change of grade is permitted at summits and 0.05% per chain at sags.ⓘ Permissible Grade given Length [P_N]

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Formula

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Permissible Grade given Length

Formula

`"P"_{"N"} = "N"/"L"`

Example

`"0.18"="3.6"/"20m"`

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Permissible Grade given Length Solution

STEP 0: Pre-Calculation Summary

Formula Used

Permissible Rate = Change in Grade/Length of Vertical Curve
P_N = N/L
This formula uses 3 Variables

Variables Used

Permissible Rate - Permissible Rate is the maximum allowable rate of change in grade for vertical curves. For railway work 0.1% rate of change of grade is permitted at summits and 0.05% per chain at sags.
Change in Grade - Change in grade is the algebraic sum of two grades in the vertical curve. It is expressed in percentage.
Length of Vertical Curve - (Measured in Meter) - Length of Vertical Curve is determined by the permissible rate of change of grade or from centrifugal consideration as appropriate.

STEP 1: Convert Input(s) to Base Unit

Change in Grade: 3.6 --> No Conversion Required
Length of Vertical Curve: 20 Meter --> 20 Meter No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

P_N = N/L --> 3.6/20

Evaluating ... ...

P_N = 0.18

STEP 3: Convert Result to Output's Unit

0.18 --> No Conversion Required

FINAL ANSWER

0.18 <-- Permissible Rate

(Calculation completed in 00.004 seconds)

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Created by Chandana P Dev

NSS College of Engineering (NSSCE), Palakkad

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Meerut Institute of Engineering and Technology (MIET), Meerut

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< 19 Surveying Vertical Curves Calculators

Sight Distance when Length of Curve is Less

Go Sight Distance SSD = 0.5*Length of Curve+(100*(sqrt(Height of Observer)+sqrt(Height of Object))^2)/((Upgrade)-(Downgrade))

Length of Curve when Sight Distance is More

Go Length of Curve = 2*Sight Distance SSD-(200*(sqrt(Height of Observer)+sqrt(Height of Object))^2)/((Upgrade)-(Downgrade))

Length of Curve when S is Less than L

Go Length of Curve = Sight Distance SSD^2*((Upgrade)-(Downgrade))/(200*(sqrt(Height of Observer)+sqrt(Height of Object))^2)

Velocity given Length

Go Vehicle Velocity = sqrt((Length of Curve*100*Allowable Centrifugal Acceleration)/(Upgrade-(Downgrade)))

Sight Distance when S is Less than L and h1 and h2 are same

Go Sight Distance SSD = sqrt((800*Height of Vertical Curves*Length of Curve)/((Upgrade)-(Downgrade)))

Sight Distance when S is Less than L

Go Sight Distance = (1/Tangential Correction)*(sqrt(Height of Observer)+sqrt(Height of Object))

Allowable Centrifugal Acceleration given Length

Go Allowable Centrifugal Acceleration = ((Upgrade)-(Downgrade))*Vehicle Velocity^2/(100*Length of Curve)

Length of Curve Based on Centrifugal Ratio

Go Length of Curve = ((Upgrade)-(Downgrade))*Vehicle Velocity^2/(100*Allowable Centrifugal Acceleration)

Upgrade given Length based on Centrifugal Ratio

Go Upgrade = (Length of Curve*100*Allowable Centrifugal Acceleration/Vehicle Velocity^2)+(Downgrade)

Sight Distance when Length of Curve is Less and Both Height of Observer and Object is Same

Go Sight Distance SSD = (Length of Curve/2)+(400*Height of Vertical Curves/((Upgrade)-(Downgrade)))

Downgrade given Length based on Centrifugal Ratio

Go Downgrade = Upgrade-(Length of Curve*100*Allowable Centrifugal Acceleration/Vehicle Velocity^2)

Length of Curve when S is Less than L and h1 and h2 are same

Go Length of Curve = ((Upgrade)-(Downgrade))*Sight Distance SSD^2/(800*Height of Vertical Curves)

Length of Curve when Height of Observer and Object are Same

Go Length of Curve = 2*Sight Distance SSD-(800*Height of Vertical Curves/((Upgrade)-(Downgrade)))

Length of Curve given Change in Grade where S is more than L

Go Length of Curve = 2*Sight Distance SSD-(800*Height of Vertical Curves/Change in Grade)

Length given S is Less than L and Change of Grade

Go Length of Curve = Change in Grade*Sight Distance SSD^2/(800*Height of Vertical Curves)

Tangential Correction

Go Tangential Correction = (Upgrade-Downgrade)/4*Number of Chords

Permissible Grade given Length

Go Permissible Rate = Change in Grade/Length of Vertical Curve

Change of Grade given Length

Go Change in Grade = Length of Vertical Curve*Permissible Rate

Length of Vertical Curve

Go Length of Vertical Curve = Change in Grade/Permissible Rate

Permissible Grade given Length Formula

Permissible Rate = Change in Grade/Length of Vertical Curve
P_N = N/L

What is vertical curve?

A curve used to connect two different grade lines of railways or highways is called a vertical curve. Such a curve is introduced to round off the angle and to obtain a gradual change in the gradient so that the vehicles passing over it may not experience a shock or a sudden jerk.

How to Calculate Permissible Grade given Length?

Permissible Grade given Length calculator uses Permissible Rate = Change in Grade/Length of Vertical Curve to calculate the Permissible Rate, Permissible Grade given Length is maximum allowable gradient that can be given for vertical curve for safe drive of vehicles. Permissible Rate is denoted by P_N symbol.

How to calculate Permissible Grade given Length using this online calculator? To use this online calculator for Permissible Grade given Length, enter Change in Grade (N) & Length of Vertical Curve (L) and hit the calculate button. Here is how the Permissible Grade given Length calculation can be explained with given input values -> 0.18 = 3.6/20.

FAQ

What is Permissible Grade given Length?

Permissible Grade given Length is maximum allowable gradient that can be given for vertical curve for safe drive of vehicles and is represented as P_N = N/L or Permissible Rate = Change in Grade/Length of Vertical Curve. Change in grade is the algebraic sum of two grades in the vertical curve. It is expressed in percentage & Length of Vertical Curve is determined by the permissible rate of change of grade or from centrifugal consideration as appropriate.

How to calculate Permissible Grade given Length?

Permissible Grade given Length is maximum allowable gradient that can be given for vertical curve for safe drive of vehicles is calculated using Permissible Rate = Change in Grade/Length of Vertical Curve. To calculate Permissible Grade given Length, you need Change in Grade (N) & Length of Vertical Curve (L). With our tool, you need to enter the respective value for Change in Grade & Length of Vertical Curve and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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