Geometric Design

Design of Vertical Alignment

Design of Vertical Alignment Generally Highway is aligned to follow the natural topography keeping in view the drainage and other design consideration.   The vertical alignment of a highway affects: Acceleration & Deceleration Operational cost of vehicle Sight distance Vehicle speed The vertical alignment consist of two element: 1. Gradient 2. Vertical curve Gradient: It

Design of Vertical Alignment Read More »

Set Back Distance 2.21

Set Back Distance: It is clearance distance, required from the centre line of pavement/road to the obstruction in ode to maintain the adequate sight distance to the curve. The set back distance or clearance required from the centre line of horizontal curve depends upon. Required sight distance (SD) Radius of horizontal Curve (R) Length of

Set Back Distance 2.21 Read More »

Extrawidening 2.19

ExtraWidening: Extra width provide to Road at horizontal curve is called extrawidening. It is provided for following purposes: To avoid off tracking due to rigidity of wheel base. To encounter psychological tendency of driver. To increase visibility at curve. To account lateral skidding. Off tracking: Path travelled by front axle and path travelled by rear

Extrawidening 2.19 Read More »

Method of Obtaining Superelevation & Radius of Horizontal Curve 2.18

Method of Obtaining Superelevation: Introducing superelevation on a horizontal curve in the field is an important feature in construction. The full super-elevation is attained by the end of transition curve or at the beginning of the circular curve. The attainment of superelevation may be split up into two parts: Elimination of crown of the cambered

Method of Obtaining Superelevation & Radius of Horizontal Curve 2.18 Read More »

Design of Superelevation 2.17

Design of  Superelevation⇒ Design of superelevation is a complex problem for mixed traffic conditions because different vehicles are moving with different speed hence the required superelevation are also different.        In this case IRC suggest to design the superelevation for 75% of the design speed considering coefficient of friction is 0. Step.1: The

Design of Superelevation 2.17 Read More »

Superelevation & Analysis for Expression of Superelevation 2.15

Superelevation: The transverse inclination throughout the length of horizontal curve by raising outer edge counteract w.r.t. inner edge, in order to counteract the effect of centrifugal force is known as superelevation (or cant or banking). The superelevation ‘e’ is expressed as the ratio of height of outer edge w.r.t. the horizontal width, i.e Superelevation (e)=

Superelevation & Analysis for Expression of Superelevation 2.15 Read More »

Intermediate Sight Distance And Sight Distance At Intersections 2.11

Intermediate sight distance (ISD): On a horizontal curve, the requirement of overtaking sight distance can not always be satisfied. In such cases overtaking is prohibited by using regulatory signs. To provide an opportunity for overtaking operation on horizontal curves or in restricted areas, we provide intermediate sight distance, i.e. equals to twice of stopping sight

Intermediate Sight Distance And Sight Distance At Intersections 2.11 Read More »

Stopping Sight Distance 2.9

Stopping Sight Distance (SSD): The minimum distance visible to a driver ahead to safety stop a vehicle travelling at design speed without collision with any other obstruction is termed as “SSD”. It is also termed as “Absolute Minimum Sight Distance” or ” Non-Passing Sight Passing”. The stopping distance of vehicle include: Lag Distance () Braking

Stopping Sight Distance 2.9 Read More »

error: Content is protected !!
Scroll to Top