PROJECT REPORT ON HIGHWAY DRAINAGE SYSTEM
Project Report
On
Submitted By
Mr. Manoj
Kumar
Civil Engineer
Abstract
This
project attempts to design an efficient, economic and easytomaintain
“Drainage System” for the road construction.
It
is also necessary because the installation of suitable surface and subsurface
drainage system is an essential part of highway design and construction.
Contents
Sr. No.

Contents

Page No.


1

Introduction

1


1.1

Historical
Background

1


1.2

Problem Statement

1


1.3

Objectives

2


2

Literature review

3


2.1

Introduction

3


2.2

Types of Drainage

3


2.3

Measures Adopted For
Surface Drainage

5


2.4

Collection Of
Surface Water

5


2.5

Classification Of
Side Drainage

5


2.6

Requirement Of
Highway Drainage System

6


2.7

Design Of Surface
Drainage

6


2.8

Hydraulic Design

7


3

Data Analysis

10


3.1

Rainfall Data

10


3.2

Data Representation

11


3.3

Determination of Runoff

12


3.4

Peak design Flow

12


4

Design of New Side Drainage

14


4.1

Design For
Trapezoidal section

14


4.2

Design for
Rectangular section

17


5

Conclusion & Recommendation

19


6

References

20


1. Introduction
Drainage is the process of interception and removal of water from over, and under the
vicinity of the road surface. Drainage can be surface (where water is conveyed
on the road surface and drainage channels) or subsurface (water flows
underneath the pavement structure).
Surface
and subsurface drainage of roads critically affects their structural integrity,
life and safety to users and is thus important during highway design and
construction. Road designs therefore have to provide efficient means for
removal of this water; hence the need for road drainage designs.
Drainage
facilities are required to protect the road against damage from surface and
subsurface water. Traffic safety is also important as poor drainage can result
in dangerous conditions like hydroplaning. Poor drainage can also compromise
the structural integrity and life of a pavement. Drainage systems combine
various natural and manmade facilities e.g. ditch, pipes, culverts, curbs to
convey this water safely.
1.1.
Historical Background:
This road is located along “G.T. Highway” in Sikandrabad, Bulandshahr,
Uttar Pradesh. It is unpaved road and is under the Sikandrabad Municipal
Council.
1.2 Problem Statement:
According to this problem of lacking side
drainage along this road, the soil surrounding the GT Highway fence has been
eroded by the water flowing during the rain, also because the water during the
rain is passing on the road, potholes has occurred on top of this road.
Therefore a drainage system has to be
designed. However, the existing road along this street is showing signs of
failure, caused mainly by lacking of drainage. Also it is better to have good
method of designing a side drainage in order to overcome these problems arises
on this road.
1.3 Objectives:
Main objective:
To design an efficient Drainage
System along this road.
Specific Objectives:
Ø To determine the catchment area and the expected flow.
Ø To collect design information for drainage system.
Ø To determination of runoff onto the road and discharge of water.
Ø To design of the drainage channels using results obtained.
Scope
of the project:
This project is confined only to designing a
drainage system for the road along the road.
Significance of the project:
The outcome of this project shall help to
propose the lay out for the new side drainage in order to fulfill its
requirements as a drainage, such as to drain off excess water on shoulder and
pavement edge which cause considerable damage and improve pedestrian safety
using side walk ways near side drainage.
Methodology:
Ø Site visiting
Ø Visiting web sites and Internet
Ø Literature review
Ø Questionnaire method
Ø Photographing
Ø Leveling
2.0
Literature Review
2.1
Introduction:
Highway drainage is the process of
interception and removal of water from over, under and in the vicinity of the
pavement.
Highway
drainage is one of the most important factors in road design and construction.
If every other aspect of the highway design and construction is done well but
drainage is not, the road will quickly fail in use due to ingress of water into
the pavement and its base.
The
damaging effects of water in the pavement can be controlled by keeping water
out of places where it can cause damage or by rapidly and safely removing it by
drainage methods.
Improper drainage of roads can lead to:
Ø Loss of strength of pavement
materials
Ø Hydroplaning
Ø Mud pumping in rigid pavement
Ø Stripping off the bituminous s
surface in flexible pavements
2.1.1 SubSurface
Drainage
Subsurface
drainage is concerned with the interception and removal of water from within
the pavement. Some of the sources of subsurface water include; infiltration
through surface cracks, capillary rise from lower layers, seepage from the
sides of the pavement to mention but a few.
Application
of side slopes on the road surface, installing of drainage beds in the pavement
and use of transverse drains are some of the measures of effecting subsurface
drainage.
2.1.2
Surface Drainage
Surface
drainage deals with arrangements for quickly and effectively leading away the
water that collects on the surface of the pavement, shoulders, slopes of
embankments, cuts and the land adjoining the highway.
The
main source of surface water in most places is precipitation in form of rain.
When precipitation falls on an area, some of the water infiltrates in to the
ground while a considerable amount remains on top of the surface as surface run
off.
2.1.3
Cross Drainage
When
stream have to cross a roadway or when water from a side drainage have to be
diverted to water course across the roadway, then a cross drainage work such as
culvert or small bridge is provided.
On
less important roads, in order to reduce the construction cost of drainage
structures, sometimes submersible bridges or course way are constructed. During
the flood the water will flow over the road
2.2
Measures Adopted For Surface Drainage
Ø The proper cross slope should be
provided for both to pavement and shoulders
Ø The subgrade should be sufficiently
above the highest level of ground water table or the natural ground level
Ø Side drainage should have to be
provided at edges of rightofway where the road is in embankment and the edge
of the roadway in cutting
Ø On hill roads, water may flow towards
the road depending on the slope and rainfall
Ø Catch water drains should be provided
to intercept the flow down.
2.3
Collection Of Surface Water
The
water collected is lead into natural channels or artificial channels so that it
does not interfere with the proper functioning of any part of the highway.
Surface
drainage must be provided to drain the precipitation away from the pavement
structure.
2.4
Classification Of Side Drainage
2.6 Requirement of Highway Drainage
System
Ø The surface water from the carriage
way and shoulder should effectively be drained off without allowing it to
percolate to sub grade
Ø The surface water from the adjoining
land should be prevented from entering the roadway.
Ø The surface drainage should have
sufficient capacity and longitudinal slope to carry away all the surface water
collected.
Ø Flow of surface water across the road
and shoulders and along slopes should not cause formation of erosion.
2.7 Design Of Surface Drainage
Ø Hydrological analysis
Ø Hydraulic analysis
2.7.1
Hydrological analysis
This
deals mainly with precipitation and runoff in the area of interest. When
rainfall, which is the main source of water, falls onto an area some of the
water infiltrates into the soil while the remaining portion either evaporates
or runs off.
The
portion that remains as runoff is the one of major importance in the design of
surface drainage facilities.
2.7.2
Determination
of runoff
Runoff
at a particular point is determined with respect to a given catchment area and
depends on a number of factors such; type and condition of the soil in the
catchment, kind and extent of vegetation or cultivation, length and steepness
of the slopes and the developments on the area among others.
The
following formula known as the rational formula is used for calculation of
runoff water for highway drainage.
Q = 0.028*C*I*A
Where:
Q = maximum runoff in m^{3}
per sec
C = runoff coefficient depending
upon the nature of the surface
I = the critical intensity of
storm in mm per hour occurring during the time of concentration.
A = the catchment area in km^{2}
2.8 Hydraulic
Design
Once
the design runoff Q is determined, the
next is the hydraulic design of drains. The side drainage and other structures
are designed based on the principles of flow through open channels.
If
Q is the quantity of surface water (m^{3}/sec) to be removed by a side
drainage and V is allowable velocity of flow (m/s) on the side drainage, the
area of cross section A of the channel (m^{2}) is found from the
relation below:
Q=A*V
The
velocity of unlined channel must be high enough to prevent silting and it
should not be too high as to cause erosion. The allowable velocity should be
greater than one (1m/sec) for lined channel.
The
slope S of the longitudinal drain of known or assumed cross section and depth
of flow, may determined by using Manning’s formula for the design value of
velocity of flow V, roughness coefficient n and hydraulic radius R.
Manning’s Formula
V={1/n}*R^{2/3}*S^{1/2}
^{}
Where:
V = Average velocity m/sec
n = Manning’s roughness
coefficient
R = Hydraulic radius
S = Longitudinal slope of
channel.
Manning’s Roughness coefficient
n = 0.02 for unlined ordinary
ditches
= 0.05 to 0.1 for unlined
ditches with heavy vegetation
= 0.013 for rough rubble
= 0.04 for stone riprap
= 0.015 for pipe culverts
Hydraulic Radius
Hydraulic
radius = [Cross sectional area]
[Wetted perimeter]
Time of concentration (T_{c})
Time
of concentration is that time required for water to travel all al the way from
catchments area to the designed element.
The
time taken by water to flow along the longitudinal drain is determined from the
length of the longitudinal drain L of the nearest cross drainage or a water
course and allowable velocity of the flow V in the drain.
T = V/L
The
total time for inlet flow and flow along the drain is taken as Time of concentration or the design
value of rain fall duration.
T_{c }=
T_{1 }+ T_{2}
Where,
T_{1 }= overland
flow time in minute
T_{2 }= is
channel flow time in minute
T_{1} =[0.885(L)^{3/H}]^{0.385}
Where,
L = the length of
overland flow in km from critical point of the mouth of the
drain.
.
H = total fall of level
from the critical point to the mouth of the drain in meters.
Note:  From the
rainfall intensity –duration frequency curves the rainfall I is found in
mm/sec. Corresponding to duration T and frequency of return period.
The
required depth of flow in the drain is calculated for convenient bottom width
and side slope of drain. The actual depth of the open channel drain may be
increased slightly to give a free body. The hydraulic mean radius of flow R is
determined.
The
required longitudinal slope S of the drain is calculated using Manning formula
adopting suitable value of roughness coefficient.
2.0
Data Analysis
2.1
Rainfall Data
The
following are the rainfall data in Sikandrabad, which obtained from the Hydrological
Department. The data are of 11 years from 2000 to 2010 {in mm/hr}.
Maximum Rainfall Intensity Duration
Frequency Data In One Day Per Year (mm/Hour)
YEAR

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

2000

28.2

26.7

44.6

143.8

30.1

10.5

3.8

15.8

3.9

1.0

102.6

120.7

2001

225.1

23.5

179.1

108.5

47.7

16.9

1.0

3.0

0.4

0.2

43.3

55.7

2002

124.8

136.3

151.6

220.3

103.8

7.6

1.6

15.8

43.0

97.8

36.8

131.9

2003

33.0

49.2

53.0

39.4

128.3

14.3

2.8

0.1

7.3

23.0

18.1

76.2

2004

79.6

75.9

52.8

97.6

10.5

10.2

0.5

1.0

7.3

30.9

28.3

80.4

2005

14.0

13.2

120.9

130.1

68.5

6.8

3.1

2.2

2.9

58.7

86.5

23.1

2006

36.5

79.4

214.1

291.7

117.9

17.6

7.2

3.7

41.0

58.4

186.9

186.2

2007

70.2

26.0

150.2

112.3

94.0

8.2

4.3

36.1

12.4

21.4

59.5

79.9

2008

27.6

77.7

3.1

2.3

22.6

6.3

4.4

1.2

4.2

0.0

84.2

20.2

2009

47.0

47.6

36.1

123.8

49.7

6.4

0.0

0.0

52.9

144.9

128.5


2010

83.6

106.2

95.9

314.3

49.7

1.3

6.3

0.8

3.0

0.8

11.6

78.0

Maximum Monthly Rainfall
2.1
Data Presentation
In
case of this road, open side drain of trapezoidal and rectangular have to be
provided for disposing of surface water collected. The first step will be to
estimate the amount of surface water flowing, the amount of surface water
depend upon the intensity of rainfall, amount of rainfall, nature of the soil
and topographical of the area. Therefore the quantity of water that can be
handled by this ditch or drain can be estimated.
Year

Maximum rainfall per month (mm)

2000

143.8

2001

225.1

2002

220.3

2003

128.3

2004

80.4

2005

130.1

2006

291.7

2007

150.2

2008

84.2

2009

144.9

2010

314.3

From
the graph the maximum rainfall intensity in the given years (20002010) is
314.3mm/hr.
2.2
Determination
of Runoff
Run off at a particular
point is determined with respect to a given catchment area and depends on a
number of factors such as type and condition of the soil, kind and extent of
vegetation (cultivation), length and steepness of the slope and development of
the area among the others.
2.3
Peak
Design Flow
This
is the maximum flow rate of a flood wave passing a point along a stream. As the
wave passes the point, its flow increases to the maximum and recedes. It is a
major factor in culvert designs, and its magnitude is dependent on the section
of the return period.
Catchment Areas (Area Data)
v Unpaved gravel road surface and
shoulders:
Length of the area=0.685km
Width of the area=0.008km
Area = Length*Width
= 0.685*0.008
= 0.00548km^{2}
v Area of land on the other side drain:
(Build up area) = 0.021*0.8
= 0.02km^{2}
v Area covered with grass:
= 0.0234*0.214
= 0.005km^{2}
v
Total catchment
area (A) = 0.03km^{2}
Surface runoff coefficient (C)
Ø Coefficient of gravel surface=0.35
Ø Coefficient of build up=0.8
Ø Coefficient of soil covered with
grass=0.1
Therefore C1=0.35, C2=0.8, C3=0.1
Weighted value of runoff Coefficient:
C = {C1A1 + C2A2 + C3A3}/{A1
+ A2 + A3}
= {0.35*0.00548
+ 0.8*0.02 + 0.1*0.005}/{0.00548 + 0.02 + 0.005}= 0.614
Therefore
the runoff coefficient (C) =0.614
Peak flow (Q)
From the formula : Q=0.278*C*I*A
Where:
Q= Quantity of rain water surface runoff in m^{3}/sec
C= Surface runoff coefficient
I= Maximum rainfall intensity in mm/hour
A= Size of surface area to be drained in km^{2}
Now, C=
0.614
I= 314.3 mm/hour
A= 0.03km^{2}
Q= {0.278 * 0.614
* 314.3 * 0.030 * 10^{6}}/{60 * 60}
Q= 0.447m^{3}/sec
Therefore, Quantity of rain water surface runoff (Q)
= 0.447 m^{3}/sec
4.0
Design of New Side Drainage
4.1 Design For Trapezoidal section
Cross
section area (A) of the side drainage required will be obtained from the
formula below;
Q = A*V
Where;
Q = Quantity of rain water surface
runoff in m^{3}/sec
A = Cross section area in m^{2}
V = Velocity of flow in m/sec
Now
we have
Q = 0.447m^{3}/sec
V = 1.5m/sec for lined structure
A =?
Therefore,
A = Q/V
A = 0.447/1.5
A = 0.298m^{2}
Therefore,
the required cross section area is 0.298m^{2}
Consider the trapezoidal section below:
f=free water body=150mm
Required Dimensions:
Ø Suppose the bottom width (b) =0.5m
Ø Side slope (S) =1:1
Ø Free water body = 0.15m
Ø Vertical height (d) =?
Ø Horizontal length (B_{1}) =?
From the formula
Area = 0.5*(B_{1} + b)*d
Area (A) = 0.298m^{2}
B_{1} = 2d+0.5m
b = 0.5m
0.298 = 0.5*(2d + 0.5+ 0.5)*d
0.298 =0.5 (2d + 1)*d
d^{2} +0.5 d0.298 = 0
d = 0.35m
B = (2* 0.35) + 0.5 =1.2m
D = (0.35+0.15) = 0.5m
= Length of two side slope +
Bottom length
Where Bottom length = 0.5m
And Length of side slope is
calculated below
From
Pythagoras theorem,
S^{2
}= d^{2}+d^{2}
S =
(0.35^{2}+0.35^{2})^{1/2}
S =
0.495m
Wetted
perimeter = 0.495+0.495+0.5
= 1.49m
Longitudinal slope
From Manning’s formula
V = 1/n*R^{2/3}*S^{1/2}
And therefore S = (n*V/R^{2/3})^{2}
Where;
S
= Longitudinal slope
V
= Velocity of flow in m/sec
R = Hydraulic Radius
n = Manning’s roughness coefficient
Hydraulic
Radius = Cross section area ÷
Wetted perimeter
R = 0.298 ÷ 1.49
R = 0.2m
n = 0.04
V = 1.5m/sec
S = [0.04*1.5 / (0.2)^{2/3}]^{2}
S = 0.0307
Therefore, the proposed slope for the side drainage
is 0.0307
4.2 Design for
rectangular section
From the formula
Q = A* V
Where Q, A and V are already defined before
Q
= 0.447m^{3}/sec
V
= 1.5m/sec
A
= ?
Q = A*V
0.447 = A*1.5
A = 0.298m^{2}
Required
dimension
Ø Suppose the
bottom width = 1.2m
Ø Free water
body = 0.15m
Ø Vertical
height =?
Consider the formula of rectangular section:
Area (A) =Height * Width
Now,
Height (d) =?
Width
(b) =1.2m
Area =
0.298m^{2}
0.298 = 1.2*d
d =0.25m
D =0.25
+ 0.15m
D =0.4m
Longitudinal
slope is
also calculated from the Manning’s formula:
V =
1/n*R^{(2/3)}*S^{(1/2)}
R
= Area divided by Wetted Perimeter
Wetted perimeter = (1.2*2) + (0.25*2) = 2.9
R = 0.298/2.9
R = 0.103,
n =0.04,
V =1.5m/sec
Now by S =
(n*V/R^{2/3})^{2}
S = {0.04*1.5/0.103^{2/3}}^{2}
S = 0.0745
5.0 Conclusion
After this research many problems were discovered
such as potholes, corrugations, water lodging, ruts ,erosion on the edge of the
road as the result of inspection, practical checking of the whole road and all
areas surrounding the road.
In order to maintain the life span and purpose of
the road as designing Road side drainage of adequate size and capacity, the
discharge and all dimensions produced can be used for the construction as it
designed.
Recommendation
Since
the condition of the drainage along G.T. Road is not satisfactory, therefore this
problem must be taken into consideration together with the information gathered
on the road conditions.
6.0
References
[1]
IRC, “Road Drainage Practice Around The
World”, Special publication, Indian Road Congress.
[2]
Luthin J.N., “Drainage Engineering”, Wiley Eastern (P) Ltd.
[3]
DSIR, “Soil Mechanics for Road Engineers” HMSO London.
[4]
Khanna S.K, “Highway Engineering”, Nem Chand & Brothers.
[5]
Cedergren, H.R., “Design of Highway & Airfield Pavements”, John Willey
& Sons.
Appendices
1.
Booking Sheet For Leveling
BS

IS

FS

RISE

FALL

RL

REMARKS

0.08

BM 0.080


0.235

0.08

0+000


1.16

0.925

0.845

0+030


1.372

0.212

0.633

0+060


1.465

0.093

0.54

0+090


1.71

0.245

0+120


0.71

0+120


1.173

0.463

0+150


1.513

0.34

0+180


2.169

0.656

0+210


0.115

0+210


0.989

0.874

0+240


1.825

0.836

0+270


2.621

0.796

0+300


3.3

0.679

0+330


0.249

0+330


2.179

1.93

0+360


0.949

0.933

0+360


1.882

0+390


3.349

1.467

0+420


0.12

0+420


1.687

1.567

0+450


3.232

1.545

0+480


0.232

0+480


1.559

1.327

0+510


2.323

0.764

0+540


2.87

0.547

0+570


3.672

0.802

0+600


1.295

0+600


1.773

0.478

0+630

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