Week 1 Challenge

AIM : to design the highway road

INTRODUCTION  : this project contains many useful concepts like super elevation, diagrammetic representations , designing summary report which includes some informations like design speed of the road , terrain classification, travel lane width etc. typical roadway project life cycle workflow and typical set of submission needed for roadway project.

 

PROCEDURE : first of all we will be creating DSR that is designing highway report for some items for city highway that im aware in my region .

name of the highway : city highway

location : kle college road Nippani.

a) class of the road : city road

b) design of the speed road : since its the small city road its design speed remain between 50km/h and if its in case of hilly region it will be 25 km/h.

in other cases , like state highway or national highway it is 100km/h and in case of hilly region it will be 50 km/h. for major district road it is 65 km/h and in case for hilly region it will be 40 km/h. for other district roads it is 65km/h and 30 km/h in case of hilly region . small city road or village road includes 50 km/h and 25 km/h in case of hill places. 

c) terrain classification : it depends for different topographies.

1) carriage way / pavement : 3.8 m , which will be single lain with camber. it is the main part of the road road on which vehicles moves, which will be done with help of camber. camber is raised region in the centre of the road, it avoids standing of water on the road , which protects road from damping and damaging, its made in a such way that water is flown from surface of the road that is pavement and is furthure moved to shoulders and then to near by drainages.

2)berm or shoulder : slope is 1 in 40 with width of 2.5m. berm is expalined as region that is made at both side of the pavement , which is also called as shoulder.

3) formation of width: it is the width of the road in a final conclusion which includes pavement width and berm width.

4)drains : water gets collected from the road pavements because of camber. since water is flown from pavements its then collected in drainages and furthure they may be utilised as per need.

d) travel lane width : * single lane road : 3.8 m

*double lane width : 7.5m

*three lane width : 10.6 m

*four lane width : 7.5 + 7.5 m

it depends on some of the factors like 

*volume of the traffic

*type of the traffic

*weight of the vehicle

*surface of the pavement

typical roadway project life cycle flow

4 ) super elevation : super elevation reduces the the effect of centrifugal force on the running wheels . if its not provided with entire centripetal force is produced by friction between vehicles tires and the roadway , thus results in reducing the speed of the vehicles.

centrifugal force of the vehicle traversed in a horizontal curve is counterbalanced by

*vehicle weigh composition due to super elevation

* side friction between tires and surface.

e + f = `v^2/15`R

where * e=super elevation rate in decimal format

*f= side friction factor

*v = vehicle speed , mph

*R = curve, radius, feet

higher rate creates problems at lower speed in snowy condition . maximum super elevation is lowered in urban facilities at adjucent buildings, lower design period and intersections are limiting factors. maximum rate of 4% can be used for urban streets. maximum rate of 6 to 8% used for urban free ways and rural highways.

importance of geometrical parameters : geometric design helps in positioning of physical elements of roadway according to standards and constraints. the basic objectives in geometric design are to optimize the efficiency and safety while minimizing cost and environmental damage.

horizontal allignment in a road design consists of straight sections of a road , known as tangents connected by circular horizontal curves . circular curves are defined by radius and deflection angle . the design of horizontal curve entails the determination of a minimum radius , curve length and objects obstructing the view of the driver. using AASTHO standards , an engineer works to design the road that is safe and comfortable . if horizontal curve has high spees and small radius , an increased superelevation is needed in order to assure safety. if there is a object obstructing the view around the corner or cure, the engineer must try to ensure that drivers can see far enough to avoid an accident or accelerate to join traffic. 

vertical profile of a road consists of a road slope called grades, connected by parabolic vertical curves. vertical curves are used to provide gradual change from one road slope to another, so that vehicle may smoothly navigate the grade changes as they travel.

sag vertical curves are those that have tangents slope at the end of the curve that is higher than that of the beginning of the curve , when driving car the sag curve should look like valley, with the vehicle first going downhill before reaching the bottom of the curve and continuing the uphill or level.

crest vertical curves are those that have tangents slope at the end of the curve that is lower than that of the beginning of the curve. when driving on crest curve the road appears as hill, with the vehicle first going uphill before reaching the top of the curves and continuing the down hill. the profile also affect on the drainage. 

typical set of submission needed for roadway project. 

• cover sheet
• index sheet
• project layout
• typical section
• plan and profiles
• plan only
• design cross section
• traffic control plans
• quantities
• summary of quantities