### Discussion :: Surveying - Section 1 (Q.No.3)

Take Lomdak said: (Sep 19, 2013) | |

How & why it is parabolic? can you please make me clear. |

Ajay Pandey said: (Oct 15, 2013) | |

Because two gradients are vertical and positive so shape is parabolic. |

Sumit said: (Nov 20, 2013) | |

How can you say that the two gradients are positive? |

M.Bhavya said: (Dec 24, 2013) | |

Because they given it is a vertical curve so it is parabolic. |

Shubham Srivastav said: (Jan 15, 2014) | |

But if falling grade meets rising grade it can be negative. |

Om Prakash said: (May 21, 2014) | |

Vertical curve is parabolic(specification). Length is calculated by means of a circular curve. |

Madhusmita Sahoo said: (Aug 13, 2014) | |

Vertical curve is parabolic(specification). Length is calculated by means of a circular curve. |

Take Lomdak said: (Sep 17, 2014) | |

What is parabolic? |

Take Lomdak said: (Sep 17, 2014) | |

What is parabolic? |

Bujji said: (Jan 21, 2015) | |

Two points not in same level. |

G.Mahesh said: (Jan 29, 2015) | |

If the vertical curve is negative what is curve? |

Shubham Choursiya said: (May 6, 2015) | |

Use the parabolic curve (or second degree curve) in vertical curve, because the rate of change of curve of parabola is constant. |

Shalini said: (Jun 2, 2015) | |

What is curve? |

Swapnil Rathod said: (Aug 20, 2015) | |

Ideal vertical curve join the two gradient and safe to move any vehicle and angle of inclination. |

Abhishek said: (Sep 14, 2015) | |

What is gradient means here!? |

Parabolic said: (Sep 15, 2015) | |

How it will be parabolic? |

Nilanthi said: (Oct 1, 2015) | |

All other shapes are 2D. But, to connect two gradients it should be a parabolic which can be drawn in 3D. |

Reuben said: (Jan 11, 2016) | |

A rising gradient of 1 in 40 is to be connected with a falling gradient of 1 in 75 by means of a vertical equal tangent parabolic curve 400 m in length. The reduce level at the intersection point of the tangent is 26.850. Calculate: (1) The rate of change of grade. (2) The reduced levels at the beginning and end tangent points. |

Mahesh said: (Jan 27, 2016) | |

The main design criteria in a vertical curve is headlight sight distance. So I think it may be circular as the sight distance available at each point is same. |

Garima Varshney said: (Jan 28, 2016) | |

Because rate of change of gradient in parabolic curve is constant. So generally used parabolic type of curve. |

Prashanth said: (Jun 7, 2016) | |

The gradient is nothing but a slope. And the best way to join 2 gradients using a vertical curve is obviously using a parabolic one. |

Nitil Verma said: (Apr 17, 2017) | |

Why it is parabolic? Give me an accurate answer. |

Amit said: (May 1, 2017) | |

The Ideal vertical curve will be circular. |

Prashant said: (May 11, 2017) | |

Parabolic curve. |

Amit said: (May 17, 2017) | |

The Ideal vertical curve is circular. |

Akshu said: (Jun 29, 2017) | |

Ideal vertical curve is circular if sight distance available throughout the length of curve is constant it possible only in case of Joining one Gradient. In this case, two gradient are Joint by curve therefore sight distance is not constant throughout the length of curve so we provide Simple Parabolic curve. |

Shuvam Dey said: (Aug 21, 2017) | |

Parabolic is done beacause in case of parabolic sight distance is large visible. |

Sathish said: (Sep 10, 2017) | |

A is the right answer. |

Varun said: (Sep 19, 2017) | |

Ideal curve is circular but parabolic is provided. |

Rotam said: (Nov 2, 2017) | |

Well you guys are too good at making simple things unexpectedly complicated. |

Sadaf said: (Nov 22, 2017) | |

The rising gradient is change 0.025 and falling 0.013333 beginning tanget elevation is 21.85 and end tangent elevation is 24.18. |

Jubayer Islam said: (Feb 15, 2018) | |

How it will be parabolic? |

Rohan Mehta said: (Jun 19, 2018) | |

In highway engineering, we deal with two type of vertical curves summit and valley. IRC CLEARLY have defined the ideal vertical curves for summit it is circular and for valley it is cubic. |

Dhanu said: (Jun 20, 2018) | |

How it is happen? Please explain. |

Subhash Kumar said: (Jul 31, 2018) | |

A cubic spiral is suitable to cubic parabola but latter is used mostly because of its ease in setting out. Vertical curves are provided to negotiate the gradient of the two straights. Parabola is most suitable shape for vertical curves since it provides a uniform rate of change of gradient and smooth riding condition. |

Atul said: (Oct 26, 2018) | |

Ideal curve is circular as per irc code. |

Anwar said: (Feb 15, 2019) | |

Curves are two types they are Summit curve and valley curve. And the best ideal curve is Summit curve. |

Obaidb said: (Apr 27, 2019) | |

Because the parabolic curve can be either sag or summit curve, in both the cases parabolic curve provides the best curve to provide maximum comfort to the passengers pr driver. |

Ajay said: (May 29, 2019) | |

Option A is the correct answer. |

Pradipta Majumder said: (May 18, 2020) | |

Correct answer is circular. Ideal summit curve is circular. But IRC recommend parabola. |

Asif Jamal said: (Oct 19, 2020) | |

Ideal vertical curve is circular if sight distance available throughout the length of curve is constant it possible only in case of Joining one Gradient. In this case, two gradient are Joint by curve therefore sight distance is not constant throughout the length of curve so we provide Simple Parabolic curve. |

Atul said: (Nov 2, 2020) | |

Ideal vertical curve is circular if sight distance available throughout the length of curve is constant it possible only in case of Joining one Gradient. In this case, two gradient are Joint by curve therefore sight distance is not constant throughout the length of curve so we provide Simple Parabolic curve. |

Anupam said: (Apr 10, 2021) | |

A) Circular is the correct answer. |

Basharat Rabani said: (Jul 20, 2021) | |

Ideal vertical curve is circular but vertical curve provided in field is square parabola for summit curves and cubic parabola for valley curves. |

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