roadworks report

CHAPTER 4ROADWORK

4.1 ROADWORKS

4.2 IntroductionRoad network is essential because it will link us to any place that we plan to travel.Ensuring the road network functions efficiently and safely is a priority for our company; MEGA BINA.A road should be designed based on the standard code of practice to ensure the uniformity and safety of all road users such as the community, cyclists, pedestrians, and etc.Our new roads is located in a develop area where road need to be prepared and designed within the area to ensure the traffic movement is not affected. For the main intersection, there will be a signalized system between the existing main road and access road of proposed development due to the increasing traffic volume in that area. The material that will be used in this project is asphaltic concrete including the road and parking area for cars and motorcycles. For pedestrians walkway, we will use interlocking pavement or concrete segmental pavement due to the safety and environmental aspects.

4.3 ObjectivesThe objectives of this project of road design are:1. To design a road network to facilitate resident.2. To build and design an economical, efficient, safe, and user-friendly road system.

4.4 Scope of WorksThe scope of work involves are:1. Estimation and design of average daily traffic (ADT)2. Proposed road levels, Internal traffic circulation3. Calculation and design of structural pavement and cross section of road4. Calculation and design of horizontal and vertical alignment5. Calculation and design of intersections/junctions

No. 2, Jalan Kebudayaan 7, Taman University, 81320 Johor Bahru Johor

4.5 ROAD DESIGN

4.4.1 Estimation and design of ADT

In order to design road, we must take into account local average daily traffic condition so that the traffic flow in the resident area can be manage to a good condition. A new traffic system needs to apply at that area to improve the existing intersection. Data on a traffic volume are very valuable in the analysis of traffic system at any roads. In this study, there are two ways of method that has been conducted to get the traffic volume at main intersection which are by doing a traffic count manually at main intersection or by using Road Traffic Volume Malaysia 2010 (RTVM 2010) to get the Average Daily Traffic (ADT).The censuses are carried out in the months of March/April and September/October from 1993 to 2010 by the respective District Public Works Department (JKR) staff, coordinated by the Highway Planning Unit (HPU).

4.4.2 Data available in RVTM 2010

a) Detailed ground survey of road corridor andb) Traffic volume from the Highway Planning Unit report. Traffic count was carried out by the JKR District at the Johor Bahru Gelang Patah (JR201).

Table 1.1: Location Description

DistrictStation No.Route No.KmDescription of Location

Johor BahruJR201J419.3Johor Bahru Gelang Patah

Table 1.2: Average Traffic Volume

16 Hours42,254

Cars and taxis (%)63.2

Vans and utilities (%)4.3

Medium Lorries (%)3.3

Heavy Lorries (%)1.3

Buses (%)1.2

Motorcycles (%)26.6

Peak Hours3,840

[Type here]

Table 1.3: Annual Growth

Growth(%)R sqr

0.15%0.04

4.4.3 Activities involve

As Preliminary Process, the activity involves are gathering and reviewing background information such as traffic and accident data, preliminary hydraulics information, aerial photos and as-built plans; conducting a field review of the project with the appropriate people in attendance (e.g. personnel from various engineering disciplines, environmental, maintenance and district construction); and writing and distributing a report summarizing the project scope, feasible alternatives, engineering decisions, level of environmental involvement, public involvement process and other issues.

Project Identification

Designate Road Group According to Nature of Area Road Traverse

Select road category base on functionSelect road category based on function

Estimate ADT at end of design life

Determine design standard

Route location

Survey and design

Figure 1: Flow Chart for the Procedure of Design Road

Road design process requires a comprehensive evaluation of future conditions in the geograhic region which may be impacted by the construction. For example, construction of new highway may change the land accessibility and land use pattern in its area of influence. Such change should be considered very carefully.

4.4.4 Symbols and legends

NoSymbolIndication

1ADTAverage Daily Traffic

2CHChainage

3CSCircular to Spiral Curve Point

4emaxMaximum Super elevation

5ESAEquivalent Standard Axle

6PCUPassenger Car Unit

7QVolume

8RTVMRoad Traffic Volume of Malaysia

9SCSpiral to Circular Curve Point

10SFPeak Hour Volume

11STSpiral Curve to Tangent Point

12TCTangent to Circular Point

13TSTangent to Spiral

4.4.5 Calculation

Estimation of ADT for 20 years

According to Guide on Geometric Design of Road ATJ 8/86, ADT is defined as the total traffic for the year divided by 365 or the average traffic volume per day. ADT is important for many purposes such as determining annual usage as justification for proposed expenditures, or for design structural elements of road. The projected ADT is also used to designate standard of road.

By referring to the Road Traffic Volume Malaysia 2006 (RTVM 2006), we can obtain some important data to estimate ADT for designed period 20 years. For the road in Skudai area from Johor Bahru Gelang Patah (JR 201), ADT obtained for year 2006 is 56,108 vehicles. The normal growth rate obtained is 3.24% based on the annual growth rate and 16 hrs traffic volume from year 1993 to 2010 stated in RTVM 2010.

For the calculation of ADT at the end of design period (Vx), we can use the formula as follows:

Vx= V0 (1 + r )xWhere:Vx= Volume of daily traffic after x years in one directed V0= Initial daily traffic in one directionx= Design period

ReferenceCalculationRemarks

RTVM 2010

ATJ 8/86 Cl. 3.2.1Data available:Avg flow in 16 hr/day in year 2010, V2010 = 42,254 veh/day Normal growth rate, r = 3.25%

For major road, For ADT 2010 :V2010=42254 veh / 16 hr=2640.9 veh/hr / 2 lane=1321 veh/hr/lane

We assume that the construction of this project will only begin by year 2015.

For ADT 2015 :V2015=V2010 (1 + r)x=1321 veh/hr .(1 + 0.0325)5=1550veh/hr/lane @ 24800veh/day/lane

Assume daily capacity in proposed zone area, Zone A is 10% of the daily capacity of the main road (Johor Bahru, Gelang Patah)V2015=1502 x 10%=150 veh/hr/lane @ 2400 veh/day/laneAssume that in this proposed site, each house will have two cars. There are 866 units of cluster house, 201 unit of semi-detached house, and 116 unit of Bungalows house. Total number of house is 1183 unit.

Estimation for 20 years :V2034=V2014 (1 + r)x=24021 veh/day. (1+0.0325)20=2847veh/hr/lanegrfdscsc

1183 houses x 2 cars = 2366 veh/day/lane V2015= 24800 + 2366 = 27166 veh/day/laneInside the proposed zone area, the daily capacity of main road is V2015 = 2400 + 2366 = 4766 veh/day/lane

Estimation for 20 years :V2035=V2015 (1 + r)x=27166 veh/day. (1+0.0325)20 =51503 veh/day/lane = 3219 veh / hr/ lane

4.5Topography and land use

The location of a road and its design are considerably influenced by the topography, physical features, and land use of the area traversed. Geometric design elements such as alignment, gradients, sight distance and cross-section are directly affected by topography and must be selected so that the road designed will reasonably fit into those natural and man- made features and economize on construction and maintenance. The topography through which the road passes can generally be divided into three groups. They are:

a) Flat TerrainTopography condition where highway sight distances, as governed by both horizontal and vertical restrictions, are generally long or could be made to be so without construction difficulty or expertise. (G% = < 3%)

b) Rolling TerrainTopography condition where the natural slope consistently rise above and fall below the road or street grade and where occasional steep slope offer some restrictions to normal horizontal and vertical roadway alignment. (G% =3% - 25%)

c) Mountainous TerrainTopography condition where longitudinal and transverse changes in the elevation of the ground with respect to the road or street are abrupt and where benching and side hill excavation are frequently required to obtain acceptable horizontal and vertical alignment. (G% = > 25%)

G 0 0

Height of contour, DeltaY mDistanceof one section,DeltaX m

ReferenceCalculationRemarks

For major road, the proposed level is differ from 14.8m-30.0m.Hence, G% = (30-14.80) /322.769 x 100%= 4.7% (3%-25%)Topography condition is rolling terrain.

For main proposed roads inside the proposed zone area, there are two segments of roads which will given different G%.Segment 1G% = 30.0m 25.0m x 100% 325m= 0.26% < 3%Topography condition is flat terrain.

Segment 2G% = 30.0m 20.0m x 100% 290m= 6.89% < 3%Topography condition is rolling terrain.

Based on the calculation above, it shows that the topography condition for this area is a Flat Terrain.

4.6 Design of structural pavement and cross section of road

4.6.1 DESIGN STANDARDS FOR BOTH MAJOR ROAD AND PROPOSED ROAD IN THE ZONE

In order to achieve the road design standard, the geometric design of all roads needs to be standardized for the following reasons:

a) To provide uniformity of the roads according to their performance requirementsb) To provide consistence, safe and reliable road facilities for movement of trafficc) To provide a guide for less subjective decision on road design

Road can be divided into two groups, urban area and rural area, urban area is defined as a roads within a gazette Municipality limits or township having a population of at least 1,000 where the buildings and houses are gathered and business activity is prevalent. However, any roads outside the Municipality limits are considered rural area. In urban areas, roads are divided into four categories, namely Expressway, Arterial, Collector and Local Street. In rural areas, roads are divided into five categories such as Expressway, Highway, Primary Road, Secondary Road and Minor Road. The summary of road classification is shown in the figure 1 below.

ROADS

Urban AreaRural Area

1. Expressway2. Arterial3. Collector4. Local street1. Expressway2. Highway3. Primary Road4. Secondary Road5. Minor Road

Figure 2: Summary of Road ClassificationThe design standard can be classified into six groups for rural area (R) and also six groups for urban area (U). Each of these standards is listed below with descending order of hierarchy.a)Standard R6/U6a) Standard R5/U5b) Standard R4/U4c) Standard R3/U3d) Standard R2/U2e) Standard R1/U1

Normally, roads which function to provide a long distance travel or heavier traffic will require a higher order of design standard for road design. Table 2.1 below show that the design standard for all the road categorized in rural and urban area.

Table 2.1: Design Standards

AreaProjected ADTRoad Category

All traffic volume

>10000

10000to 3000

3000to 1000

1000to 150

38 cm = TA

Wearing CourseBinder CourseRoad-base CourseSub-base CourseHence, the pavement structure of the major road will comprise of the following layer:Wearing course = 10 cm Binder course = 15 cm Road base course = 35 cm Sub-base course = 35 cm

For the road pavement inside the proposed zone,Wearing course= 5 cm Binder course= 6.5 cm Road base course = 30 cm Sub-base course = 15 cm

Pavement structure detailThe cross-section pavement design of the roads is shown inAppendix 1

10 cmD115 cm

D235 cm

D335 cm

Wearing CourseBinder CourseRoad-base CourseSub-base Course

5 cmD16.5 cm

D230 cm

D315 cm

4.7DESIGN SPEED

Speed is a primary factor in all modes of transportation and is an important factor in the geometric design of roads. The speed of vehicles on a road depends to the capabilities of the drivers and their vehicles, upon general conditions such as the physical characteristics of the highway, the weather, the presence of other vehicles and the legal speed limitations.

Design speed is defined as a maximum safe speed selected to establish specific minimum geometric design elements for a particular section of highway. The choice of design speed is influenced primary by factors such as the design standard, category of road and the type of the terrain of the roads. Table below shows the design speed for rural and urban roads.Table 2.3: Design Speed for the Rural Road

Table 2.4: Design Speed for the Urban Road

From the table above, the design speed of the main road in this project is 80 km/hr through the assumption that the area is Type I while for the roads in the proposed zone are 90 km/hr. However, for the purpose of safety, we decide that the design speed of 90 km/hr is being reduced to 50 km/hr.

4.8HORIZONTAL AND VERTICAL ALIGNMENT

4.8.1HORIZONTAL ALIGNMENT

In the design of horizontal curves, it is necessary to establish the proper relation between the design speed and curvature and also their joint relations with super elevation(e) and side friction (f). There are two types of curves that being considered which are Circular Curve and Transition/Spiral Curve. The combination of circular and spiral curve can give the best design of horizontal alignment with the certain design speed.

CIRCULAR CURVE

The minimum radius is a limiting value of curvature for a given speed and is determined from the maximum rate of superelevation and the maximum allowable side friction factor. The minimum safe radius (Rmin) can be calculated from the standard curve formula.

2R V127 e f

Where:

R min = minimum radius of circular curve (m) V= Design speed (kph)e= Maximum superelevation rate= 0.1 for roads at rural area= 0.06 for roads at urban areaf= Maximum allowable side friction factor

Figure 4.1: Comparison of Side Friction Factors Assumed for Design of Different Types of RoadsTable 4.1: Minimum Radius

Design Speed (kph)Minimum Radius (m)

e = 0.06e = 0.10

110560500

100465375

90335305

80280230

70195175

60150125

5010085

406050

303530

below:

The length of the circular,Lc curve can be determined with using the equation

2 n aLC R 360Where:R= Minimum radiusA= Angle of circular curve

TRANSITION / SPIRAL CURVE

Vehicles follow a transition path as it enters or leave a circular horizontal curve. To design a road with built-in safety, the alignment should be such that a driver traveling at the design speed will not only find it possible to confine his vehicle to the occupied lane but will be encouraged to do so. Spiral transition curve are used for this purpose. The degree of curve varies from zero at the tangent end of the spiral to the degree of the circular arc at the circular curve end. The length of spiral, Ls can be calculated from the equation below:

Where:

Ls = v3 [ 1 R.g.e / v2 ]cR

v= Speed (m/s)c= rate of increase of centripetal accelerating (m/s3)= 1 to 3 (m/s3)R= Radiusg= Gravity acceleration (m/s2) e= super elevation rate

CalculationRem arks

Angle of spiral curveEs = 57.3 x 13.0512R= 57.3 x 13.0512 x 70= 5.342o

Angle of circle curvea = E - 2Es= 13 (2 x 5.342o)= 2.316o

Circle curve length Lc = R x 2rra360= 70 x 2rr x 2.316o360= 2.83 m

Total curve length L = Ls + Lc + Ls= 13.051 + 2.83 + 13.051= 28.932 m

Attaining Superelevation CURVE 1Chainage of TS = 5153.11 m Chainage of SC = 5166.16 m Chainage of CS = 5168.99 m Chainage of ST = 5182.04 m

emax = 9.1%

X+9.1%TSSCCSST

-2.5%

X = Tangent Runout= (2.5/9.1) x 13.051= 3.59 mThe detailing of the horizontal alignment is shown in Appendix 2.

CalculationRem arks

CURVE 2

LSLC

RRES a

Data:V=40 km/h = 11.11 m/s f=0.12e=0.06E=30c=1.0 m/2

Minimum radius:R = 70 m (same as above)

Length of spiral:Ls = 13.051 m (same as above)

LS

E = 30o

Angle of spiral curve:Es = 5.342o

Angle of circle curvea = E - 2Es= 30 (2 x 5.342o0 == 19.316o

CURVE 2

LSLC

RRES a

Data:V=40 km/h = 11.11 m/s f=0.12e=0.06E=30c=1.0 m/2

Minimum radius:R = 70 m (same as above)

Length of spiral:Ls = 13.051 m (same as above)

Angle of spiral curve:Es = 5.342o

Angle of circle curvea = E - 2Es= 30 (2 x 5.342o)= 19.316o

LS

E = 30o

Circle curve length Lc = R x 2rra360= 70 x 2rr x 19.316o360= 23.6 m

Total curve length L = Ls + Lc + Ls= 13.051 + 23.6 + 13.051= 49.702 m

Attaining Superelevation CURVE 2Chainage of TS = 5099.99 m Chainage of SC = 5113.04 m Chainage of CS = 5136.64 m Chainage of ST = 5149.69 m

emax = 9.1%

X+9.1%TSSCCSST

-2.5%

X = Tangent Runout= (2.5/9.1) x 13.051= 3.59 mThe detailing of the horizontal alignment is shown in Appendix 2.

4.8.2 VERTICAL ALIGNMENT

INTRODUCTION

Vertical curve are used to effect a gradual change between tangent grades. They should be simple in application and should result in a design that is safe, comfortable in operation, pleasing in appearance and adequate for drainage. For the simplicity, the parabolic curve with an equivalent vertical axis centered on the vertical point of intersection is used.

The design calculations in this particular chapter of vertical curve were based on the engineering surveying method. There are two types of vertical curve which are crest curve and sag curve. Crest curve is the grades meeting at summits whereas sag curve is the grades meeting at valleys. Also, grades are represented in terms of ratio or percentages.Rising grades are known as +ve and those descending as ve.

In vertical curve design, calculations are based on the algebraic difference between gradients. In addition, the type of curve usually used is the parabola because a parabola has a uniform rate of change of gradients from the geometric point of view. Thus, yielding a uniform rate of vertical radial force.

VERTICAL CURVE CALCULATION

ROAD 1For the calculation of vertical curve 1 p = 0.00%q = 0.667 % L = 112.5m

(p q)% qByC

pL

AL

Chainage1059(A)10341009984959946.5934

x (m)0255075100112.5125

dh on grade (xp/100)0000000

RL grade (RLA +dh)24242424242424

Offset (y) y = [(p- q)/400L]x2

0

0.009

0.037

0.083

0.148

0.188

0.232

RL on curve2423.99123.96323.91223.85223.81223.768

909884859834

150175200225

0000

24242424

0.3340.4540.5930.75

23.66623.54623.40723.25

For the calculation of vertical curve 2 p = 0.667%q = 0.000 %L = 112.5mL C L

q%

Ayp%B

(p q)%

Chainage834(A)809784759734721.5709

x (m)0255075100112.5125

dh on grade (xp/100)00.1670.3360.50.6670.750.838

RL grade (RLA +dh)23.2523.08322.91422.7522.18322.522.412


0

0.009

0.037

0.083

0.148

0.188

0.232

RL on curve23.2523.09222.95122.83322.33122.31222.644

684659634609

150175200225

22.2522.08321.91621.75

0.3340.4540.5930.75

22.58422.53722.53722.5

22.58422.53722.50922.5

ROAD 2

For the calculation of vertical curve 1 p = 0.00%q = 0.727 % L = 112.5m

(p q)% qByC

pL

AL

Chainage2944(A)296929943019304430693081.5

x (m)0255075100125137.5


RL grade (RLA +dh)24242424242424


0

0.009

0.037

0.083

0.148

0.188

0.232

RL on curve2423.99123.96323.9127.988.178.34

309431193144316931943219

150175200225250275

000000

242424242424

0.3340.4540.5930.750.8261

23.66623.54623.40723.2523.17423

For the calculation of vertical curve 2 p = 0.667%q = 0.000 %L = 112.5mL C L

q%

Ap%

yB(p q)%

Chainage3219(A)324432693294331933443356.5

x (m)0255075100125137.5

dh on grade (xp/100)00.1820.3640.3450.7570.9461.041

RL grade (RLA +dh)2322.81822.63622.45522.24322.08421.958


0

0.008

0.033

0.074

0.132

0.207

0.250

RL on curve2423.99223.97723.92623.86823.79323.768

336933943419344434693494

150175200225250275

1.1361.3251.5141.7031.8932.082

0.3340.4540.5930.7521.10720.918

0.2970.4050.5290.6690.8261

22.16122.0822.01521,96621.93321.917

ROAD 3


(p q)% qByC

pL

AL

Chainage4585(A)461046334660465547104757.5

x (m)0255075100125137.5


RL grade (RLA +dh)24242424242424


0

0.009

0.037

0.083

0.148

0.188

0.232

RL on curve2423.99223.97723.92623.86823.79323.768

473547604785481048354860

150175200225250275

000000

242424242424

0.3340.4540.5930.750.8261

23.70323.59523.47123.33123.17423


LLC

q%

Ayp%B

(p q)%

Chainage4860(A)488549104935496049854997.5

x (m)0255075100125137.5

dh on grade (xp/100)00.1820.3640.3450.7570.9461.041

RL grade (RLA +dh)2322.81822.63622.45522.24322.08421.958


0

0.008

0.033

0.074

0.132

0.207

0.250

RL on curve2322.82622.66922.52922.37522.26122.209

501050355060508551105135

150175200225250275

1.1361.3251.5141.7031.8932.082

0.3340.4540.5930.7521.10720.918

0.2970.4050.5290.6690.8261

22.16122.0822.01521,96621.93321.917

ROAD 4

For the calculation of vertical curve 1 p = 0.00%q = 0.667 % L = 150m

(p q)% qByC

pL

AL

Chainage3550(A)357536003675370037253750

x (m)0255075100125150


RL grade (RLA +dh)24242424242424


0

0.007

0.028

0.063

0.111

0.174

0.250

RL on curve2423.99323.97223.93723.88923.82623.75

377538003825385038753900

175200225250275300

000000

242424242424

0.3400.4500.5630.6950.8411

23.6623.5523.43723.30523.15923

For the calculation of vertical curve 2 p = 0.667%q = 0.000 % L = 150 mLLC

q%

Ayp%B

(p q)%

Chainage3900(A)392539503975400040254050

x (m)0255075100125150

dh on grade (xp/100)00.1670.3340.50.6670.8341.000

RL grade2322.83322.66622.522.38322.16622

(RLA +dh)


0

0.007

0.028

0.063

0.111

0.174

0.250

RL on curve2322.8422.69422.56322.44422.34022.25

407541004125415041754200

175200225250275300

1.1681.3341.51.6681.8342

21.83221.60621.521.33221.16621

0.3410.4500.5630.6950.8411

22.17322.03622.06322,02722.00722

4.9 JUNCTION

INTRODUCTION

Road intersections whether at grade or grade separated are an important component of a road system. It is through these points that the motorists and other road users gain access to the road network. Generally the capacity of major intersections controls the volume of traffic within the system. These intersections also represent the points of conflict in the road networks as the traffic stream will cross, merge, diverge and weave at these locations. Proper design for these intersections will greatly enhance the safety of the road users and improve the capacity of the system.

For high speed expressway, grade separated interchanges are used to control access where mobility is of greater importance. However for lower standard roads in rural and urban area where accessibility is more important, at-grade intersections are used. The common types of at grade and grade separated intersections are:

a) T-Junction,b) Y-Junction,c) Staggered Junction,d) Cross Junction,e) Roundabout,f) Trumpet Interchange,g) Diamond Interchange,h) Cloverleaf Interchange, andi) Directional Interchange.

Intersections at grade present a driver with several points of conflict with other vehicles. The aims of intersection design are to improve traffic flow and reduce the likelihood of accidents. This is achieved by controlling vehicle maneuvers and reducing the number of points of conflict. The principal factors influencing the design of an intersection are:a) Traffic volume and characteristics,b) Topography and environment,c) Economic considerations, andd) Human factors.

Safety is a prime consideration in any intersection design. Safe intersection design is based on the following principles:a) Reduction of the number of points of conflict,b) Minimising the area of conflict,c) Separation of points of conflict,d) Giving preference to major movements,e) Control of speed,f) Provision of refuge areas, traffic control devices and adequate capacity, andg) Definition of paths to be followed.

The objective of intersection design is to reduce the severity of potential conflicts between vehicle while providing maximum convenience and ease of movement to vehicles. Four basic elements are generally considered in the design at-grade intersection which are:a) Human factors such as driving habits and decision and reaction time.b) Traffic considerations such as capacities and turning movements, vehicle speeds and size and distribution of vehicles.c) Physical elements such as characteristic and use of abutting property, sight distance and geometric features.d) Economics factors such as cost and benefits and energy consumption.

,.1 l\ ,, lo 1 u

CL 2.3ATJ 11/87

CL 3.5.1 ATJ 11/87

T 2-2BATJ 11/87Assumption: The type of junction is T-Junction (3 arms Junction). There are obstructers blocks the view to recognize the traffic sign or traffic signals at intersection. The velocity for major road is 80 km/hr. The velocity for minor road is 40 km/hr. Heavier approach of minor road is 150 veh/hr. Heavier approach of major road is more than 600 veh/hr.

Type of intersection:

II

In design at the grade junction, we choose to design three arms.The type of intersection design is Unsignalized Intersection which connect Collector road (U5) to the Secondary road (R5).

1. Minimum Design Speeds for Left Turn ChannelDesign Speed of approach road , v = 80 km/hrMinimum design speed of left turn Channel , v = 40 km/hr

Cl. 3.5.3 ATJ 11/87

Cl. 3.5.4 ATJ 11/87

Figure 3-8C ATJ 11/87

Figure 3-8B ATJ 11/87

Figure 3-10 ATJ 11/87

2. RadiusR1= V2 / 127 (e+ f )= 402 / 127 ( 0.06 + 0.28 )= 37.1 m 40.0 m

3. Right Turn LaneLength of Right Turn Lane Storage Length, LR = 2 xM x S Where:M = 600 veh/hr/60 min = 10 veh/min LR = 2 x 10 x 12 = 240 mBut, in this case, we adopt Lmin = 20 m

Design speed, V = 80 km/h Yd = width of right turn lane= 3.5 mTherefore, width of central island, W = 2.5 m

Length of taper, LT = 1/3 V (Yd)1/2= 49.89 50 m

Right Turn Clearance, E = 1100Therefore, R = 16.5 mW = 8 m

Table 3.2 ATJ 11/87

Table 3.12 ATJ 11/87

Table 3.12 ATJ 11/87

Table 3.3 ATJ 11/87

Figure 3.13 ATJ11/87

Cls 3.7.34. Left Turn Lane Major RoadDesign speed of approach road = 80km/h Minimum design speed of left turn lanes = 40 km/h

Turning Radius, R1:V =40 km/h (Turning speed)Coefficient of friction between tyres and pavement, f = 0.28 Superelevation of curve, e = 0.06 (Urban area)Therefore, R1 = 43 m

Minor road

Design speed of approach road = 40 km/h Minimum design speed of left turn lanes = 30 km/h

Turning Radius, R1:V = 30 km/h (Turning speed)Coeffition of friction between tyres and pavement, f = 0.28 Superelevation of curve, e = 0.10 (Rural area)Therefore, R1 = 18 m

Lane Width for Left Turn LaneArea = Rural (R4)Category of road = Secondary Road Lane Width = W1

W2 = 5.9m , adopt 7m S = 1.3 m

Cls 3.7.3



5. Design of Separate Left Turn Lanes Taper Length For Major RoadTd = ( V/3.6) x ( Yd /0.9 )Yd = 3.5 m= ( 80/3.6) x ( 3.5 /0.9)= 86.4 m, adopt 100 m

Tm = ( V/3.6) x ( Ym /0.6 )Ym = 3.5 m= ( 40/3.6) x ( 3.5 /0.6)= 64.8 m, adopt 65 m

Taper Length for Minor roadV= 40 km/hr (the velocity for minor road) Yd = 3.5 m (desirable treatment)Td = [V/3.6] x [Yd/0.9]Td = 43.2 m, adopt 45 m

V= 30 km/hr (minimum design speed for turn-left channel) Ym = 3.5 m (desirable treatment)Tm = [V/3.6] x [Ym/0.6]Tm = 48.6 m, adopt 50 m

Deceleration Lanes Major roadDesign speed of approach road = 80 km/h Design speed of exit curve = 40 km/h Length of deceleration Lanes = 94 m Treatment in approach to Left Turn

58 | Indah Boulevard Project58

Acceleration LanesDesign speed of road being entered = 80 km/h Design speed of exit curve = 40 km/hLength of acceleration lanes = 180 m Treatment for acceleration lane taper

CONCLUSION

As a conclusion, all the calculations done are meeting the standard requirement.From the computation of 20 years design life, the 2 lanes used in this design can provide a smooth journey for the road user. Besides that, the designed road had shown that the horizontal and vertical curves are computed to give an ease movement to the vehicles.Finally, the intersection suggested determines that it can reduce the severity of potential conflicts between vehicles, at the same time, it provides a convenience for the road user. Overall, it can be said that this designed road has fulfilled the important criteria in term of cost, safety, and quality.

roadworks report

Documents