GRADUATION THESIS ROAD AND HIGHWAY SECTION

The ideal capacity of the road, Nlt is the capacity which is determined in ideal condition including the road condition and vehicle condition + Assumption: vehicle continuously move on t

CONTENT

PREFACE 4

PART I 5

CHAPTER 1: INTRODUCTION 6

1.1 BACKGROUND OF THE PROJECT 6

1.2 OUT LINE OF THE PROJECT 6

1.3 DOCUMENTS USED FOR DESIGNING 7

CHAPTER 2: PROJECT AREA IN THANH HOA PROVINCE 9

2.1 INTRODUCTION AND GEOGRAPHICAL CONDITIONS 9

2.2 TOPOGRAPHICAL CHARACTERISTIC 9

2.4 HYDROLOGY 13

2.5 CONSTRUCTION MATERIALS 13

2.6 DETERMINATION OF ENVIRONMENT 14

2.7 TRAFFIC CONDITIONS OF THE REGION 14

CHAPTER 3: DETERMINE THE TECHNOLOGY FACTORS OF ALIGNMENT 15

3.1 DETERMINE ROAD LEVEL 15

3.2 CAPACITY OF THE ROAD 16

3.3 SPECIFIC GEOMETRY OF CROSS SECTION 18

3.4 DETERMINE SIGHT DISTANCE 21

3.5 DETERMINE MAXIMUM GRADES OF THE ROAD 24

3.6 DETERMINE MINIMUM RADIUS OF HORIZONTAL CURVE 26

3.7 WIDENING IN CURVE 28

3.8 DETERMINE SUPERELEVATION AND SUPERELEVATION TRANSITION 29

3.9 SPIRAL CURVE 30

3.10 ENSURE SIGHT DISTANCE IN HORIZONTAL CURVES 31

3.11 ENSURE SIGHT DISTANCE IN PROFILE 32

3.12 TOTAL GEOMETRIC FACTOR OF THE ROAD 36

CHAPTER 4: ALTERNATIVE ROUTES ON THE PLAN 37

4.1 OVERALL DESIGN 37

4.2 PRINCIPLES FOR ALIGNMENT SELECTION 38

CHAPTER 5: PROFILE DESIGN 40

5.1 GENARAL CONTROLS FOR VERTICAL ALIGNMENT 40

5.2 ARRANGE VERTICAL CURVE IN PROFILE 40

5.3 COMBINATION OF HORIZONTAL AND VERTICAL CURVE 41

CHAPTER 6: ROAD-BED DESIGN 44

6.1 DEFINED TYPES OF MATERIAL CAN USE MAKING ROAD BED 44

6.2 DEFINED TALUS OF ROAD BED 44

6.3 DEMAND OF COMPACTNESS AND LOADING CAPACITY OF ROAD BED 45

6.4 TYPICAL CROSS SECTION OF ROAD BED 46

6.5 EXCAVATION AND FILL VOLUME 46

CHAPTER 7: PAVEMENT DESIGN BASE ON 22TCN 221-06 61

7 1 PAVEMENT STRUCTURE AND REQUIREMENT 62

7 2 FLEXIBLE PAVEMENT STRUCTURE 63

7 3 FLEXIBLE PAVEMENT STRUCTURE DESIGN 63

CHAPTER 8: DRAINAGE SYSTEM 76

8.1 DESIGN CULVERT 76

8.2 DESIGN SIDE DITCH 80

CHAPTER 9: SAFETY FACILITIES OF ROAD 83

9.1 SIGN 83

9.2 MAKER POST, KMSTONE, GUARDRAIL 84

9.3 ROAD MARKING 85

PART II 169

CHAPTER 1: INTRODUCTION 104

1.1 BACKGROUND OF THE PROJECT 104

1.2 OUT LINE OF THE PROJECT 104

CHAPTER 2 : ALTERNATIVE ROUTES ON THE PLAN 124

2.1 DETERMINE ROAD LEVEL 106

2.2 CAPACITY OF THE ROAD 107

2.3 SPECIFIC GEOMETRY OF CROSS SECTION 108

2.4 DETERMINE SIGHT DISTANCE 111

2.5 DETERMINE MAXIMUM GRADES OF THE ROAD 114

2.6 DETERMINE MINIMUM RADIUS OF HORIZONTAL CURVE 116

2.9 SPIRAL CURVE 118

2.7 ENSURE SIGHT DISTANCE IN HORIZONTAL CURVES 118

2.8 ENSURE SIGHT DISTANCE IN PROFILE 119

2.10 TOTAL GEOMETRIC FACTOR OF THE ROAD 123

CHAPTER 3 : ALTERNATIVE ROUTES ON THE PLAN 124

3.1 OVERALL DESIGN 124

3.2 PRINCIPLES FOR ALIGNMENT SELECTION 125

CHAPTER 4 : PROFILE DESIGN 127

4.1 GENARAL CONTROLS FOR VERTICAL ALIGNMENT 127

4.2 ARRANGE VERTICAL CURVE IN PROFILE 127

4.3 COMBINATION OF HORIZONTAL AND VERTICAL CURVE 128

CHAPTER 5 :ROAD-BED DESIGN 130

5.1 DEFINED TYPES OF MATERIAL CAN USE MAKING ROAD BED 130

5.2 DEFINED TALUS OF ROAD BED 130

5.3 DEMAND OF COMPACTNESS AND LOADING CAPACITY OF ROAD BED 131

5.4 TYPICAL CROSS SECTION OF ROAD BED 132

5.5 EXCAVATION AND FILL VOLUME 132

CHAPTER 6 : ALTERNATIVE ROUTES ON THE PLAN 124

6.1 PAVEMENT STRUCTURE DESIGN 138

6.2 CALCULATION PARAMETERS AND SECTION FLEXIBLE PAVEMENT STRUCTURE 139

6.3 FLEXIBLE PAVEMENT STRUCTURE DESIGN 138

CHAPTER 7 : DETAIL DESIGN OF PILE CULVERT 145

7.1 DESIGN CULVERT 145

7.2 DETAIL OF SIDE DITCH 145

CHAPTER 8: DETAIL DESIGN OF HORIZONTAL CURVE 159

8.1 DESIGN DATA 130

8.2 SETTING OUT OF THE CURVE 130

8.3 ATTAINMENT OF SUPERELEVATION 131

8.4 SUPERELEVATION RUN OFF 132

8.5 E PAVEMENT WIDTH IN CURVE 132

CHAPTER 9: SAFETY FACILITIES OF ROAD 159

9.1 TRAFFIC SIGNING 159

9.2 MAKER POST, KMSTONE, GUARDRAIL 160

9.3 ROAD MARKING 161

PART III : SPECIAL SUBJECT 169

CHAPTER I: INTRODUCTION 170

1.1OBJECTIVES OF THE SURVEY 170

1.2TESTING METHODS 170

CHAPTER II: SURVEYING RESULTS 180

2.1 HANG BONG STREET 180

2.2 HANG VOI STREET 185

CHAPTER III: PAVEMENT CONDITION ASSESSMENT 188

3.1 PAVEMENT CONDITION INDEX (PCI) 188

3.2 PAVEMENT STRENGTH ASSESSMENT 193

3.3 PAVEMENT ROUGHNESS ASSESSMENT 194

PREFACE

In the career of building and protecting country, Communication and Transport are essential contributing important roles Along with country's continuous development in the past years, field of capital construction generally and civil engineering construction in particular have invested by Government and Party and having deservedly proud achievements In the next years, in order to implement the career of modernization and industrialization, Communication and Transport must precede a step, serve purposes of socio-economic development

In the recent years, the government is investing much in Transportation and Communication; advanced constructing technologies are applied in Vietnam To apply in fact, civil engineers’ level must be better and better To satisfy demands of development, The University Transport and Communication is opening scope and raising quality of training

After learning and gathering knowledge in the University Transports and Communications, now I am designing a graduation thesis about the road and highway I am

guided directly by Associate Professor – Doctor Tran Thi Kim Dang and other lectures

in the Road and Highway section, Civil engineering department of the Hanoi university of

transports and communications I thank the lectures of the subject, especially Associate

Professor – Doctor Tran Thi Kim Dang, my guide lecturer and Master of Science Tran

Vu Tuan Phan, my revise lecturer

I have tried to do my thesis best with my knowledge, but it is not very good because

of time and some other reasons I hope advices, remarks and suggestions of teachers and all

of you

Thank to you sincerely!

Ha Noi, May-2011 Student

PART I PRELIMINARY DESIGN

CONSTRUCTION INVESTMENT PROJECT HIGHWAY ROUTE A - B CONTRUCTION PROJECT Option 1: STATION : KM0+00 TO KM4+676.16 Option 2: STATION : KM0+00 TO KM4+586.66 Nhu Xuan district, Thanh Hoa Province

CHAPTER 1: INTRODUCTION

1.1 BACKGROUND OF THE PROJECT

Project name: Highway investment project

Location: Alignment A-B is located in Nhu Xuan district, Thanh Hoa province

Project manager: Ministry of transport

Consultant organization: The University of Transports and Communications Hanoi

Designer: Do Manh Long

English Roads and Bridges Class K47

University of Transports and Communications

1.2 OUT LINE OF THE PROJECT

1.2.1 Objectives of the Project

The main objectives of the Project implementation can be summarized as follows:

The new road is strategically located at Thanh Hoa province to contribute to the economic and social development of the Central Highland region in Vietnam

Concerns and improvement for the traffic safety, job opportunity and living level of the local residents in the project area is an important factor in the sense to share the profits of project

1.2.2 The base to carry out the project

Base on Thanh Hoa Highway investment and construction policy

Base on traffic volume investigation and forecast data

The annual vehicles’ development coefficient is 7% The design traffic volume is 5484,5 (vehicle/day)

Numbers of Rear Wheel

Distance between rear axles (m)

Traffic Volume (veh/day)

PCU equivalent factors

- Small 25.0 60.0 1 Single Wheel - 98 2.0

- Large 60.0 90.0 1 Dual Wheels - 102 3.0

- Light 25.0 60.0 1 Dual Wheels - 102 2.0

- Medium 25.0 70.0 1 Dual Wheels - 98 2.0

- Heavy 50.0 100.0 2 Dual Wheels - 99 2.5

- Tractor 60.0 120.0 5 Dual Wheels > 3 m 25 3.0

Table 1-1: 1 st Year annual average daily traffic

1.3 DOCUMENTS USED FOR DESIGNING

No Name of Standards Standard Ref No

Survey

T29 Topography drawing and measuring standard 96TCN 43-90

T32 Land survey in construction – general specification TCXDVN309-2004

No Name of Standards Standard Ref No

G09 Geotechnical Boring Investigation Standard 22TCN259-2000

G13 Geological survey for waterway work standard 22TCN260-2000

G27 Procedure for static penetration testing (CPT and CPTU) 22TCN320-2004

Road Design

R16 Specifications for road design TCVN4054-2005

R28 Rural road design standard (used for frontage road and

collector road)

22TCN210-92

Pavement

P18 Vietnam Pavement standard of flexible structures 22TCN211-06

P38 Flexible pavement design (to collate with standard

22TCN211-93)

22TCN274-01

P33 Standard for solid bitumen material – technical specification

and testing method

W12 Technical classification for domestic inland waterway TCVN5664-92

W11 Flood flow calculation 22TCN220-95

W37 Design external drainage system of the structure 22TCN51-84

CHAPTER 2:

PROJECT AREA IN THANH HOA PROVINCE

2.1 INTRODUCTION AND GEOGRAPHICAL CONDITIONS

Thanh Hoa is a large province of Central Vietnam It has borders with Son La, Hoa Binh and Ninh Binh province in the north, Nghe An province in the south, the sea in the east and it also border Laos in the west

Thanh Hoa is comprised of three categories of mountain, plain and highland terrains

2.2 TOPOGRAPHICAL CHARACTERISTIC

Thanh Hóa has diverse terrain, lower from west to east, divided into three distinct areas:

- The mountainous and midland’s area is 839,037 ha, it is 75.44% of the province The average height of the mountains from 600-700 m with slopes above 25o; midlands has an average elevation of 150 - 200m and slope about 15-20o

- The delta has an area of natural land is 162,341 ha, accounting for 14.61% of the province, the accretion by the Mã river, Bạng river, Yến River and Hoạt river The average height from 5 to

15 m, interspersed with low hills and limestone exclusive lap

- The littoral zone covers an area of 110,655 ha, accounting for 9.95% of the province, with

102 km long coastline, terrain is relatively flat

2.3 CLIMATIC CONDITIONS

The climate in the project area is under highland tropical monsoon climate There are two distinct seasons: rainy season from May to October, and dry season from November to April of the following year

The monthly climatic records at Thanh Hóa are summarized in the figures given below The average annual rainfall is 2000mm at Thanh Hóa

Average temperature is 23-24 deg Cover the year

Relative humidity is high throughout the year with an average of 81%

Average wind speed varies from 14m/s to 32m/s

Annual average sunshine hours is about 1600 hours in which, during the rainy season, sunshine duration is the least and about 50-100 hours per month The most sunshine duration is from May to July, exceeding over 280 hours per month

Figure 2.1: Diagram of monthly rainfall and number of monthly rain day

Month 1 2 3 4 5 6 7 8 9 10 11 12

Rainfall

(mm) 85 88 98 110 400 900 1000 1100 1300 1200 500 100

Rainning day 2 4 6 7 10 12 14 16 17 15 9 5

Table 2.1: Number of monthly rain day in Thanh Hóa

Source: Viet Nam Climate, by Mr Pham Ngoc Toan & Mr Phan Tat Dac, Technical and Science Publisher – 1993) TN: Thanh Hóa Meteorology Station (Temperature: 1950-1970, Rainfall: 1915-1925; 1930-1945; 1955-1970, Humidity: 1958-1970, Wind: 1959-1970, Sunshine: 1958-1970)

Raining day

Raining days

Figure 2.2: Wind flower in Thanh Hóa

Wind direction Number of windy day per year Frequency

This section is prepared to provide followings:

ü To find possible material sources;

ü To determine the suitability for quality requirements;

ü To determine the possibility of supply for required magnitude in the project;

ü To provide necessary information to estimate the project cost

The Project goes through the area where constructional material sources are popular and advantageous The exploitation, supply and transportation conditions are very convenient

Soil: sandy clay volume is quite large Sandy clay has high strength Employment,

transportation is convenient So, it is used for embankment very well

Stone: The quality of stone is quite good and satisfies Resistance strength is rather high

There are some quarries with large volume Sand: the quantities are large The exploitation, supply and transportation are quite convenient

Water: is sufficient for construction

- Other environmental aspects

2.7 TRAFFIC CONDITIONS OF THE REGION

Thanh Hóa province has nearly 5000 km roads In which, national road is 398 km (7.96%), province road is 460 km (9.2%), district road and commune road is 4000km (82%)

CHAPTER 3: DETERMINE THE TECHNOLOGY

FACTORS OF ALIGNMENT

3.1 DETERMINE ROAD LEVEL

3.1.1 DESIGN TRAFFIC VOLUME

According to the highway specification TCVN 4054-2005 then: Design traffic volume is number of the passenger cars converted from all the vehicles which is forecasted to pass a cross section of the road during the time unit in the computing year ( the 20th year in this project)

3.1.2 ROAD LEVEL

Design traffic volume is number of the passenger cars converted from all the vehicles which is forecasted to pass a cross section of the road during the time unit in the computing year

Formula: Nde = ∑ (a N i i)

With: Nde : Design traffic volume (Veh/day)

Ni : Volume of vehicle type i in future year

Ni = Nip x(1+q)t

Nip: Volume of vehicle type at the present

q: Traffic growth =7%

t: Calculated time =20 (years)

ai : Equivalence factor from vehicle type i to passenger car

Vehicle Traffic Volume

(veh/day) The current year

Traffic Volume (veh/day) The Forcast year

PCU equivalent factors

- Heavy 99 358 2.5

Table 3-1: Volume of types of vehicle

So the total number of equivalence car in current year is 1516.5 veh/day

So the forecast equivalence car after 20 years is 5484.5 veh/day

- Base on design traffic volume Nde = 5484 (veh/day) > 3000 (veh/day) From the Viet Nam standard TCVN 4054-2005, the road level is level III

- Base on the importance of the road is connecting economic and politic centers of the

province

- Base on the future development plan of the province related to transport and

communication’s developments

So, the road level is chosen is: level III

Design Speed chosen is 60 km/h

3.2 CAPACITY OF THE ROAD

The capacity of the road, (N) is maximum number of vehicle that can be able to pass continuously through any cross section during time unit

N = vehicle per day (VPD) or vehicle per hour (VPH)

3.2.1 IDEAL CAPACITY OF THE ROAD

The ideal capacity of the road, Nlt is the capacity which is determined in ideal condition (including the road condition and vehicle condition)

+ Assumption: vehicle continuously move on the road, the same kind of vehicle and speed,

the distance between two adjacent vehicle is constant and equal to Lo, which is required so sufficient that if any vehicle suddenly stop then the driver of the followed on keep in time to perceive and put on the brake to stop safety Lo is called kinetic size of vehicle

+ Schema, refer to figure 3-1

L

i = 0

v

v

- l pu : distance of psychological reaction, calculate from the driver sight a obstructive object

in his path then just time to put on the brake to stop And tpu = 1 (s)

(m)3.6

v(km/h)

lpu =

- lx : vehicle length lx = 6 m

- lo : safe distance lo= 5 m

- Sh : braking distance, is calculated:

)(254

1000

2 2

i

V K

V S

lt

l l i

V K V

V N

++

±

×+

=

)(2546.3

- i : gradient of the road, in normal condition i = 0

- ϕ : longitudinal coefficient of friction, in favorite concision ϕ = 0.7

±

=1155 (veh/h)

3.2.2 ACTUAL CAPACITY OF THE ROAD

The actual capacity of the road, Ntt is the capacity which is determined in the actual condition

of the road and traffic

+ The actual capacity (Ntt)

The actual capacity is equal to (0.3 0.5÷ )N lt

So: Ntt = (0.3 0.5÷ )N lt= 346÷577 (veh/h)

Base on normal condition of the road, we have:

Ntt = 0.4Nlt = 462 (veh/h)

3.3 SPECIFIC GEOMETRY OF CROSS SECTION

3.3.1 GENERAL INTRODUCTION

Cross section is significant component for describing the road shape which is changed depending on the terrain condition

Pavement consist of carriageway and shoulder and median (if need)

When design speed is larger or equal to 40 km/h, shoulder must be treated

In the project, median is not located and shoulder is treated

3.3.2 DETERMINE THE NUMBER OF LANE

Determine the number of lane is to specify the carriageway fited traffic demand (road capacity satisfies the traffic volume)

According to the specification TCVN 4054-2005 we have:

The number of lane is determined by the formula:

nl =

cl

ph

N z

Ncl : the capacity of the lane

Z: traffic serving rate (degree of using capacity) Z = (0.55-0.77)

According to TCVN 4054-2005, with the 60km/h design speed we have Z=0,77

Lane width is determined basing on dimension and speed of vehicle

Carriageway width is determined basing on the number of lane, lane width, distance of two vehicles in the opposite direction

Figure 3-2 Determine the lane width

- a: body width

- c: Distance between two wheels

- x : Distance from edge of the body to the median

- y: Distance from the wheel to edge of part that the truck runs on

- l2: lane width, l2 =(a+c)/2+x+y

Where: x = 0.5 + 0.005V (m)

y = 0.5 + 0.005V (m) with driving contrariwise

l2 =(a+c)/2+ 1 + 0.01V

With design speed, V =60(Km/h) ⇒ l2 =0.5x(a+c) + 1.6 (m)

a Calculating for truck

l2

x

x

a

According to standard TCVN 4054-2005 we have main parameters of cross section:

+ Number of lane : 2 lanes

+ Road bed width : 9 (m)

Shoulder is the surfaced strip of roadway immediate adjacent to the carriageway edge

The faction of shoulder:

+ As a widening part of pavement to increase the safety and reliability for vehicle operation

+ For emergency stopping

+ Temporary extra traffic lanes during road maintenance or carriageway reconstruction

+ For increasing the sight capacity on the road

+ As a structural support to the pavement

+ As a manner for increasing LOS (level of service) and capacity of the road

According to Viet Nam standard TCVN 4054-2005, with road level is level III and design speed is 60 km/h, shoulder width is 1,5 (m) and treated shoulder width is 1 (m)

3.3.5 CROSS SLOPE (CROSS FALL)

In order to drain surface water from the pavement and avoid pounding in surface deformations they create a cross slope for central strip or they make the convexity of pavement and it is termed

“camber”

Depending on the type of pavement surface and the treated shoulder part is usually the same construction with carriageway In order to satisfy favorable execution, cross slope of treated

According to TCVN 4054-2005, we choose:

+ Cross slope of carriageway: 2%

+ Cross slope of treated shoulder: 2%

+ Cross slope of soil shoulder: 4%

3.4 DETERMINE SIGHT DISTANCE

Sight distance is the length of the roadway a driver can see ahead at any particular time The sight distance available at each point of the highway must be such that when a driver is traveling at the highway’s speed, adequate time is given, after an object is observed in the vehicle’s path,to make the necessary evasive maneuvers without colliding with the object The two types of sight distance are stopping sight distance and passing sight distance

Traffic safety and quality of traffic flow require minimum sight distance for stopping in time (stopping sight distance) or for safe overtaking ( passing sight distance)

Sight distance is minimum visible distance in front of the driver It is very important to calculate and provide the driver with the sign distance so sufficient that he can treat safety any case which suddenly happens when car moving on the road

Sight distance calculations, the height of the driver’s eye and height of the object are considered to be 1.0 (for the same direction) or 1.2m (for opposite direction) and 0.1 m above the road surface respectively

3.4.1 STOPPING SIGHT DISTANCE (SSD)

The stopping sight distance (SSD), for design purposes, is usually taken as the minimum sight distance required for a driver to stop a vehicle after seeing an object in vehicle’s path without hitting that object Stopping sight distance is the most fundamental of the distance considerations in highway geometric design, since adequate stopping sight distance is required at every point along the roadway This distance is the sum of the distance traveled during perception-reaction time and the distance traveled during braking

In traffic safety point of view, the required stopping sight distance,SSD, is the distance which

a driver needs in order to stop his or her vehicle before reaching an unexpected obstacle on the road when ridding at the 85% speed

Computing sight distance:

According to this scheme:

S1 = Lpr + Sh + L0 Computing sight distance depend on V(Km/h), we have:

S1 = 6.3

V

+

)(254

V

(m)

- Sh : Braking distance: Sh =

)(254

- k : coefficient of the brake using, k = 1.2 for passenger car

- ϕ : Longitudinal coefficient of friction: ϕ = 0.5

- i : Gradient of road, for unfavourable condition, we choose: i =7%

)07.05.0(254

2602.16

.3

⇒ So we choose the stopping sight distance is: S1 =75 m

3.4.2 OPPOSING SIGHT DISTANCE (OSD)

In addition to the previous discussion of stopping sight distance, some countries’ guidelines consider an additional sight distance model, which could close the gap between stopping and passing sight distance The opposing sight distance,OSD, corresponds to the roadway section which

is needed to allow two opposing vehicles to stop in time and avoid a collision It is equal to the sum

of stopping sight distance for the two vehicle For roads with traffic in opposite directions, the opposing sight distance should be available on the entire roadway section

The opposing sight distance represents a lower limiting value that guarantees safety when starting passing maneuvers Therefore, the opposing sight distance is considered a critical passing sight distance It is the minimum section length, which has to be clearly observed,in order to allow a timely stop between the overtaking vehicle and the oncoming one

Opposing sight distance S2 needs to be computed so sufficient that when moving on the single lane or narrow two lanes, the driver discovers an oncoming vehicle and just in time to stop the vehicle safely

Computing sight distance:

S2 = 2Lpr + L0 + Sh1 + Sh2 Computing sight distance follows: V(Km/h):

i

kV V

+

−

+

) (

127 8

2

ϕ = 127 ( 0 5 0 07 )

5 0 60 2 1 8 1

60

2 2

2

−

×

× + + 5 = 108.75 m

According to TCVN 4054-2005, Opposing sight distance: S2 = 150 m

⇒ So we choose: S2 = 150 (m)

3.4.3 AVOIDING SIGHT DISTANCE (ASD)

Avoiding sight distance S3 needs to be computed so sufficient that vehicle 1 is moving on the path of vehicle 2, detects the vehicle 2 and keep in time to turn to its lane for avoiding safely Calculating sight distance:

Figure 3-5: Determine avoiding sight distance

Avoiding sight distance is calculated by formula:

S3 = 2 lpr + Sh1 + Sh2+ lo According to this scheme:

Sh1 = Sh2 = 2 ar

S3 =

8.1

V

+ 4 ar + lo Where:

- a : Distance between two center of two lanes a = 3 m

- r : Turning radius

r =

) (

3.4.4 PASSING SIGHT DISTANCE (FULL OVERTAKING SIGHT DISTANCE) (FOSD)

The passing sight distance is the minimum sight distance required on a two-lane, two-way highway that will permit a driver to complete a passing maneuver without colliding with an opposing vehicle and without cutting off the passed vehicle The passing sight distance will also allow the driver to successfully abort the passing maneuver (that is , return to the right lane behind

the vehicle being passed) if he or she so desires In the determining minimum passing sight distance for design purposes, only single passes (that is, a single vehicle passing a single vehicle) are considered Although it is possible for multiple passing maneuver (that is more than one vehicle pass or are passed in one maneuver) to occur, it is not practical for minimum design criteria to be based on them

Passing sight distance S4 needs to be computed so sufficient that vehicle 1 (overtaking vehicle) would like to pass the vehicle 2 (on two lanes road), detects the opposing vehicle 3 and has to return safely to its correct lane

Figure 3-6: Determine passing sight distance

In the nomal case: S4 = 6.V = 360 m

In the compulsory case: S4 = 4.V = 240 m

According to TCVN 4054-05, passing sight distance: S3 = 350 m

⇒ we choose: S3 = 350 (m)

* Application

+ Stopping sight distance is basic value which has to be caculated in any case of the design

+ Opposing sight distance is applied th vertical curve on the road without median and sight distance offset

+ Avoiding sight distance is effect on the roads having the poor pavement and not used in the standard of America, UK, France, etc

3.5 DETERMINE MAXIMUM GRADES OF THE ROAD

3.5.1 DETERMINE MAXIMUM GRADES BASE ON DYNAMIC FACTOR

Calculation principle: Pulling force of vehicle must be larger than summary of impediment force Maximum grade is calculated depending on the capacity of vehicle type that can be overtaking slope of the road Otherwise, maximum grade is calculated depending on dynamic factor By formula:

Where:

- Dk : Dynamic factor

- f : rolling impediment coefficient: f = 0,02 (asphalt concrete pavement)

- i : grade of the road ( %)

- j : relative acceleration of vehicle j =

dt dv

- d : coefficient considering the rotation of the machine (d=1.03-1.07)

- g : gravity acceleration, g = 9.81 m/s2

( (+) when go up, (-) when go down)

Assumption: the vehicle have uniform motion, we have: j = 0

To compute in unfavorable condition: when vehicle goes up the slope

Dk / f + i ⇒ idmax= Dk – f = Dk – 0.02 With Vtt = 60 km/h, To look up the chart of dynamic factor for some type of vehicles and (in Road design book) and substitute them to above formula, take the table:

Type of vehicles Vehicles D max i max =D max -f

Table 3-2: Dynamic factor and maximum grades

Because cars are outnumbered others vehicles, we use car for design vehicle, so base on this table, the idmax = 7 %

3.5.2 DETERMINE MAXIMUM GRADES BASE ON CLINGING FORCE

According to the condition of clinging force between the types and carriageway, in order to vehicles move safety, the clinging force between the types and carriageway must larger than the pulling force of vehicle So maximum grades of the road must smaller than grades that is calculated basing on the clinging force (ib) ib is computed in case the pulling force of vehicle equal to the clinging force between the types and carriageway

Assumption: the vehicles have uniform motion, we have: j = 0

To compute in unfavorable condition: when vehicle goes up the slope

D’ = f + ib → ib = D’ - f

We have :

D’=ϕ.G b−P w

>D

Where:

- D’ : Dynamic factor

- ib : Grade of the road (base on clinging force)

- G : Whole vehicle load

- Gb : The load in positive wheel:

+ Truck: Gb = ( 0.65 ÷ 0.7 ).G + Passenger car: Gb = ( 0.50 ÷ 0.55 ).G

- ϕ : longitudinal coefficient of friction In the most unfavorable case: ϕ = 0.3

- Pw: Air impediment force

13

F V2K

P W = (kg)

Where:

- K: air impedient coefficient, depending on air density and vehicle shape

- F : Area of the maximum cross section of vehicle which is perpendicular to moving direction (air impediment area, m2)

F = 0.8BH Where: B: Vehicle width

H: vehicle height

- V: Relative speed of vehicle in comparing with air In case, there is no wind Vtt=60km/h

To look up type of vehicles datum and calculate We set a table as follows :

Vehicle type K F(m

2) Pω G(Kg) Gk(Kg) D’ ib

Car 0,03 2.88 23.9261 3636 1999.8 0.2684 0.2464 Truck (10-12t) 0,04 9 162 13625 9537.5 0.3381 0.3161 Truck (8-9t) 0,05 9 162 8250 5775 0.3303 0.3084

Truck (4-6t) 0,06 9 162 5350 3745 0.3197 0.2977

Table 3-3: Grades of the road depending on clinging force

The condition for vehicle not to slip and lose balance is ib ≥ imax All the condition checked

in this table is good

According to Viet Nam standard TCVN 4054-2005, with design speed is 60 km/h: we choose grade of the road: 7%

Combine calculation and standard, we propose to choose grade of the road is 7% in order to design AB alignment

3.6 DETERMINE MINIMUM RADIUS OF HORIZONTAL CURVE

The aim of designer is to determine the component of road to fit the demand of serving through, safely, smoothly, economically and aesthetically the traffic That is why, in principle the radius of curve should be as great as possible However, in many situations, depending on the terrain condition it is needed to use sharp curve to avoid a too great earthwork or disadvantage condition… In that case, in order to be safe for vehicle moving on outside lane of curve, the pavement should be designed the same cross-fall inclining to the center of curve (superelevation)

3.6.1 MINIMUM RADIUS OF CURVE WITH SUPERELEVATION

In disadvantage case, minimum radius of horizontal curve is calculated with superelevation 8%

Rmin =

) i 127(

µ : Lateral force coefficient, normally: µ = 0.15

iscmax : superelevation, iscmax = 7%

+0.07)15

.0(127

602

128.8 m

According to TCVN 4054-2005, minimum radius of curve with superelevation 7% is 125 m

We propose: Rscmin = 125 m

3.6.2 MINIMUM RADIUS OF NORMAL CURVE

Normal curve is the curve in which all cross section is normal cross section (without superelevation) Minimum radius of non-superelevation curve is symbolized RminKSC And RminKSC

is calculated by formula:

Rmin =

)iμ127(

602

472(m)

According to TCVN 4054-2005, minimum radius of normal curve 1500 m So, we propose: RminKSC = 1500 m

3.6.3 RADIUS OF CURVE WITH NORMAL SUPERELEVATION

In normal case, radius of horizontal curve is calculated with superelevation 4%

Rmin =

)iμ127(

µ : Lateral force coefficient, normally: µ = 0.135

isc : superelevation isc = 4%

+0.04)135

.0(127

602

149 m

According to TCVN 4054-2005, minimum radius of curve with superelevation 4% is 250 m

So, we propose: Rscmin = 250 m

3.7 WIDENING IN CURVE

While the vehicle moving in the curve, each tyre move in a different path: the constant rear axis always lead to the radial while the front axis and rear axis make an angle, so the vehicle need a bigger widening in curves Therefore, to make the moving of vehicle as comfortable as moving in the straight line, the small-radius curves (<250 according to TCVN 4054-05) need to have

widening The number of that widening have to make sure the distance between the car and the shoulder, between two cars just like in the straight line

Figure calculating widening in the curve

Refer to Figure, we have

Eg = e1 + e2 ≈ 2e2 = L2/R

Geometric widening is widening in static situation In fact, it needs to be considered in the condition

of vehicle moving In that case, due to the influence of speed, by expriment we have expression of widening (Ev)

82

+ = 0.6m L: Length from axle’s vehicle to axle of the next one, L=8m

According to TCVN 4054-05 the widening in the curve with Vtk = 60 Km/h, Rmin = 250(m) is 0.6 m

So we choose the widening in the curve is 0.6(m)

3.8 DETERMINE SUPERELEVATION AND SUPERELEVATION TRANSITION

3.8.1 SUPERELEVATION

In sharp horizontal curve, in order to increase the lateral resistance (decrease effect of centrifugal force), stability of vehicle moving on the outside lane, the surface of pavement is designed to incline to inside direction of curve That is termed “super elevation”

Super elevation must be designed to fit particular conditions Super elevation is calculated depending on design speed and radius of horizontal curve:

i sc = − μ 127R

V2

Where:

R : Minimum radius of horizontal curve with super-elevation

µ : Lateral force coefficient (µ = 0.15: ratherly perceive the curve)

V : Design speed V= 60 km/h

Substitute for calculation formula, we have:

077.0

60

According to TCVN-4054-2005, maximum rate of superelevation is 7%

Combine between calculation and standard to choose maximum rate of superelevation: 7%

i p : supplemental grade, with Vtt = 60 km/h => i p = 1%

Depend on every curves, we have different Lsc

+ Radius of orbit reduces from ∞ in tangent to R at the curve

+ Centrifugal acceleration (a) increases from 0 up to a = V2/R

+ Centrifugal force also increases from 0 up to

2

GV C gR

The length of spiral curve must be larger than superelevation transition distance, widening transition distance

The length of spiral curve is computed:

Lsp =

R

V

5.23

3

Where:

+ V: design speed, V = 60 km/h

+ R: radius of curve

With different radius of the curve, we have different value of Lsp

According to TCVN 4054-2005, with road level: 60 km/h, minimum length of spiral curve is

50 m

And according to TCVN 4054-2005:

+ When design speed is larger than or equal to 60 Km/h then spiral curve must be established

+ For transition curve, spiral curve may be subsituted by the curved:

- The curve Lemniscate Bernouilli: c

- The combination circular curves

3.10 ENSURE SIGHT DISTANCE IN HORIZONTAL CURVES

S

Z ZO

Figure 3-8: Sight distance in curves

When vehicle move on inside lane in the curve The sign of driver may be eclipsed by obstructions such as: house, trees, high cut slope … Thus, we have to consider the sight design in the curve

+ AB: sight line of driver, AB = S = calculating sight distance

+ Z: maximum distance from the orbit of vehicle moving on inside lane to AB

+ Zo: distance from the orbit of vehicle on inside lane to edge of obstruction

If: Z≤Z o then the sight of driver is adequate

Z > Zo then the sight of driver is inadequate and have to design for clearance at the inside

of the curve (determine Z)

+ Orbit of vehicle in inside lane is perceived: 1.5 m far from inside edge of carriageway

+ Driver’s eye elevation is about 1÷1.2 m

According to analysis method, there are two cases in order to determine sight distance in the curve:

+ Sight distance S is not larger than the length of curve K:

)2cos1( − α1

Z

+ Sight distance is larger than the length of curve:

2K)sin(S

2

1)2cosR(1

Where: ;: deflection angle

;1=180o.S/pR

R: radius of the curve

3.11 ENSURE SIGHT DISTANCE IN PROFILE

3.11.1 ENSURE SIGHT DISTANCE

To ensure sight distance in profile, we only consider to crest curve, because sag curve is satisfied Basing on sight distance in order to determine radius of crest curve respectively

Figure 3-9: Sight distance in vertical direction

To ensure two directions of sight distance: rmin =

ω 4d

Where:

d : drivers ‘eye height, d = 1.2 m

ω : angle of rapture ω = i1 - i2

In the case: ω = 2% ⇒ rmin: unfavorable minimum sight distance

If: rmin ≥ S1 then sight distance is satisfied

rmin < S1 then sight distance is not satisfied

2.1

4× = 240 > S1 =75(m)

⇒ Sight distance is satisfied

In the case: rmin = S1 = 75 (m)

4 ×

= 0.064 = 6.4/0

So, with ω > 6.40/0 then consider sight distance in the vertical curve

3.11.2 MINIMUM RADIUS OF VERTICAL CURVE

The vertical curve is established to make smooth, safe transition and provide a sufficient sight for vehicle moving between the adjacent grades At changed direction position which algebraic difference between two rate of grades is larger than or equal to 1% (for V ≥60Km h/ ) or 2% (for V<60 Km/h), must be designed the vertical curve The vertical curve is circular curve or parabola curve

3.11.2.1 Minimum radius of crest curve

Minimum radius of crest curve is determined by the requirements of sight distance.Crest curve

is circular curve and Rmin corresponding to the driver’s sight is equal to sight distance (s)

S

d1A

B

R

OM

Figure 3-10: Minimum radius of crest curve

d1: driver’s eye heigh

d2: obstruction heigh

R: radius of crest curve

We have:

1 S 2S

S= + = R d + d

2 2 1

2

)dd2(

SR

752

× =2343.75 m

According to TCVN–4054-2005, limited minimum radius of crest curve with design speed 60 km/h is 2500 m and normal minimum radius of crest curve is 4000 m

To propose using minimum radius = 2500 m in order to design crest curve

3.11.2.1 Minimum radius of sag curve

+ According to centrifugal force condition:

When vehicle move on the sag curve, it is compacted by gravity and centrifugal force Centrifugal itself may cause to overload for vehicle bearing So, it is important to control the value

of centrifugal force (C)

Centrifugal acceleration is determined:

bR

Va

2

≤

=

With b is allowable centrifugal acceleration, b = 0.5 ÷ 0.7 m/s2, V (m/s)

So:

2 min

V R b

=

For design, V = m/s, then b = 0.5 m/s2 So substitute for formula Rmin, we have:

Rmin=

5 6

60 6.5

3.12 TOTAL GEOMETRIC FACTOR OF THE ROAD

From technology factor calculation of alignment and combine with Vietnam standard Basing

on actual condition of the road, technology, economy, we propose to use basic technology factors of alignment that as follows:

No Technology factor unit

9 Maximum rate of grade % 6.85 7 7

10 Maximum rate of superelevation % 7.7 7 7

12 Cross slope of treated shoulder % 2 2

13 Cross slope of soil shoulder % 4 4

CHAPTER 4: ALTERNATIVE ROUTES ON THE PLAN

4.1 OVERALL DESIGN

4.1.1 SELECTION OF ALIGNMENT

Selection of main alignment direction must be based on given alignment direction (the end points and limited points), class of road and its function in road network, in addition to combine factors such as : waterway, railway, airway, pile line and state of cities, hometowns, industrial zones, capital; and combination to natural, hydro-meteorological, geological, topographical conditions as well so that from these value, through analysis and comparison we can choose the most suitable alignment

4.1.2 MAIN FACTORS IN OVERALL DESIGN

After determining horizontal alignment direction and class of road, we must arraign alignment

in integrity Some principle problems must be carried out:

+ Depending on traffic volume, characters of terrain to determine terrain type, road class and design speed

+ Besides the end points demand must be suitable with planning road network, designers have

to present alternatives of alignment joint so that in the future the alignment can be stretched

+ Determining number of lane bases on traffic volume and vehicle movement demands

+ Estimate road length, select transition points between sections suitable Solve alignment shape of sections at joint positions the best

+ Survey plane of cities, hometowns along the road, decide alternative and position of jointing them

+ Survey natural, traffic and social conditions along road, determine intersection positions

+ Basing on function of road, decide safe measurements, manage traffic, position and arrangement of bus stops, garage services

+ For tool road we need determine regulations and manner of getting expenses basing on justification

+ Overall consider position and distance of intersections, car parks, major bridges to ensure minimum distance for moving traffic safely

4.1.3 LIMITED POINTS

The end points, cities, towns and so on which alignment must be go through is limited points Major bridges and long tunnel are limited points as well

4.1.4 DESIGN ACCORDING TO SCENERY CONDITION

Following this condition, the alignment must be combined with bridges, tunnels, intersections and man works along the road harmoniously

4.2 PRINCIPLES FOR ALIGNMENT SELECTION

When determine the various components of horizontal alignment apart from the above section mentioned, designer should consider the integration of the individual components and the relationship of the horizontal alignment with the environment and surrounding terrain To avoid these evidences of poor design practices, the general controls in the following paragraphs should be used where practicable:

- Two end points of the designed alignment must be determined

- The alignment should be skirt along the path of birth as well as the contour lines

- Alignment should be as directional as possible but should be consistent with the topography and with preserving developed properties and community values A flowing line that conforms generally to the natural contours is preferable to one with long tangents that slashes through terrain

- In alignment predicated on a given design speed, use of minimum curvature for that speed should be avoided wherever possible The designer should attempt to use generally flat curves, retaining the maximum for the most critical conditions In general, the central angle of each curve should be as small as the physical conditions permit, so that the highway will be as directional as possible The central angle should be absorbed in the longest possible curve

- Consistent alignment always should be sought Sharp curves should not be introduced at the ends of long tangents Sudden changes from areas of flat curvature to areas of sharp curvature should be avoided Where sharp curvature must be introduced, it should be approached, where possible, by successively sharper curves from the generally flat curvature

- For small deflection angles, curves should be sufficiently long to avoid the appearance of a kink Curves should be at least 150 m long for a central angle of 5° , and the minimum length should be increased by 30 m for each 1° decrease (Ed: perhaps they mean increase here) in the central angle

- Anything other than tangent or flat curvature should be avoided on high, long fills In the absence of cut slopes, shrubs, and trees above the roadway, it is difficult for drivers to perceive the extent of curvature and adjust their operation to the conditions

- Caution should be exercised in the use of compound circular curves

- Any abrupt reversal in alignment should be avoided Such a change makes it difficult for a driver to keep within his or her own lane It is also difficult to superelevate both curves adequately, and erratic operation may result

-The "broken-back" or "flat-back" arrangement of curves (having a short tangent between two curves in the same direction) should be avoided except where very unusual topographical or right-of-way conditions dictate otherwise

- To avoid the appearance of inconsistent distortion the horizontal alignment should be coordinated carefully with the profile design

In accordance with given terrain feature, terrain is mainly plan and gentle hill therefore designing horizontal alignment is quite advantage in general

Design values are shown in the following table 4-1:

CHAPTER 5: PROFILE DESIGN 5.1 GENARAL CONTROLS FOR VERTICAL ALIGNMENT

When designing vertical alignment must be based on specific terrain, geological, hydrological feature in order to ensure stability condition under impact of vehicle and natural element

Ensure alignment regular change, use small grade

Ensure drainage well

A smooth grade line with gradual changes, as consistent with the type of highway and character of terrain, should be sought for in preference to a line with numerous break and short lengths of grades

A “broken-back” grade line (two vertical curves in the same direction separated by a short section of tangent grade) generally should be avoided, particularly in sag where the full view of both vertical curves is not pleasing This effect is particularly noticeable on divided roadway with open median section

On long grads, it may be preferable to place the steepest grades at the bottom and flatten the grades near the top of the ascent or to break the sustained grade by short intervals of flatter grade instead of providing o uniform sustained grade that is only slightly below the recommended maximum This particularly applicable to roads and streets with low design speed

Where at-grade intersections occur on the roadway sections with moderate to steep grades It

is desirable to reduce the grade through the intersection Such profile changes are beneficial for vehicles marking turns and serve to reduce the potential for crashes

Sag vertical curves should be advised in cuts unless adequate drainage can be provided

The length of grade line must not be larger than the critical lengths of grade

The minimum grade in cut is 0.5% in order to ensure drainage condition In the disadvantage condition minimum grade may be 0.3%

5.2 ARRANGE VERTICAL CURVE IN PROFILE

Vertical curves to effect gradually changes between tangents may be any one of the crest or sag curve types Vertical curves should be simple in application and should result in a design that is safe and comfortable in operation, pleasing in appearance, and adequate for drainage The major control for safe operation on crest vertical curves is the provision of ample sight distance for design