pavement design

DESIGN OF PAVEMENTS

Submitted by Guided byRohit Agarwal (U08CE005) Dr. N.C. Shah Anoop Ambala(U08CE027) Shri. S. RoyAnush Sadu(U08CE031)Jogi Yojitha(U08CE043)C Ajay Kumar(U08CE061)Prerit Goel(U08CE062) B.Tech IV

OBJECTIVES To do a critical study of pavement design Understand the concepts which go behind safe design of

highway pavements and urban roads To prepare a thorough report about the various factors

which affect the design of pavements, reasons for failure, estimation of the project, etc.

Attempt to redesign the existing pavement at GIDC(Pandesara) and Urban roads of Surat.

INTRODUCTION Pavement is a durable surface material laid down on an

area intended to sustain vehicular or foot traffic With technology, we can now design pavements which

can support heavy vehicular traffic for a sustained period of time

There are 2 types of pavements-1. Rigid pavements2. Flexible pavements

SUB TOPICS

There are mainly three points to be considered while designing a rigid pavement

1. Factors affecting the design.2. Actual designing.3. Designing of joints.

RIGID PAVEMENTS

FACTORS AFFECTING DESIGN OF RIGID PAVEMENT

Design wheel load

Tyre pressure

Design period

Design traffic

Temperature differential

Soil characteristics

DESIGN WHEEL LOAD Legal axle load – single, tandem, tridem axle load The legal axle load limit in India have been fixed as

follows (given in IRC:58-2002)

1.Single axle- 10.2 tonnes2.Tandem axles- 19 tonnes3.Tridem axle- 24 tonnes

Factor of safety is in general taken as 1.2 to 1.5

Tyre pressure (IRC:58-2002) In most of the commercial highways tyre pressure

ranges from 0.7 to 1 MPa A TYRE PRESSURE OF 0.8 MAY BE ADOPTED FOR

DESIGN

Design period(IRC:58-2002) Normally concrete pavement have a life span of

30 years. So anything below 30 years can be considered for

normal design

DESIGN TRAFFIC Assessment of traffic should be normally based on 7-day

24-hour count made in accordance with IRC:09 (Traffic census on non-urban roads)

Total number of Commercial Vehicle Per Day is to be calculated.(cvpd)

The actual value of growth rate is determined or else it is taken to be 7.5% annually

The cumulative number of repetition of axles during design period may be computed by the formula given in IRC:58-2002(4.4)

365*A{(1+r)^n - 1} C = ------------------------------- r

TEMPERATURE DIFFERENTIAL Temperature difference between top and

bottom of concrete of concrete slab cause the concrete slab to wrap, giving rise to stresses.

As per the guidelines of IRC:58-2002 temperature differential of 15.8 degree is adopted for the rigid pavement design

SOIL CHARACTERISTICSThe primary factors for consideration are as follows: The general characteristics of the sub-grade soils such as

soil classification, limits, etc. Depth to bed rock. Depth to water table (including perched water table). The compaction that can be attained in the sub-grade and

the adequacy of the existing density in the layers below the zone of compaction requirements.

The CBR that the compacted sub-grade and uncompacted sub-grade will have under local environmental conditions.

The presence of soft layers in the sub-soil.

CBR TESTING

TABLE NO- 01 TEST RESULTS SOURCE: M/S UNIQUE ENGINEERING TESTING AND ADVISORY SERVICES, SURAT

Sr. No Test BSNL Opp. Wintex LHS 24.0

mt wide road

Plot No-07 & 08 (Laxmi Hari RHS

decent Restraint)

Opp. Narayan Textile LHS 24.0 mt. wide road

1 Atterburg’s Limit

Liquid Limit 51 48 52

Plastic Limit 27 23 24

Plasticity Index 24 25 28

Free Swell Index 39 40 40

2 Modified Proctor Test

Maximum Dry Density in gms/cc

1.80 1.85 1.90

Optimum Moisture content in %

20.01 17.06 14.31

3 CBR (Soak) value 3.89 2.68 2.65

4 CBR (Unsoak) Value 7.47 7.89 10.43

TABLE NO- 02 TEST RESULTS SOURCE: M/S UNIQUE ENGINEERING TESTING AND ADVISORY SERVICES, SURAT

Sr. No Test Opp. Paras Prints Pvt. Ltd. LHS 20.0 mt. wide

road

Nr. Betex India Plot No-397/16.0 mt.

wide road

E1 road opp. Himalay chem.. P.

No-24-25 LHS

1 Atterburg’s Limit

Liquid Limit 51 56 50

Plastic Limit 22 30 24

Plasticity Index 29 26 26

Free Swell Index 43 32 50

2 Modified Proctor Test

Maximum Dry Density in gms/cc 1.91 1.81 1.89

Optimum Moisture content in % 16.13 16.69 16.69

3 CBR (Soak) value 2.98 3.87 3.72

4 CBR (Unsoak) Value 10.95 7.22 10.72

RIGID PAVEMENT DESIGNThe 2 branches of Rigid Pavement Design

1.Concrete Slab Thickness Design

2. Joint Design

CONCRETE SLAB THICKNESS DESIGN According to the design factors and analysis a

number of parameters are to be considered.

They are as follows Design period (n yrs) Width of the Slab (B m) Grade of Cement Concrete Tyre Pressure (p kg/cm2) Rate of traffic Growth (r %) Soil sub grade charectersticks Poisson Ratio (µ)

Effective modulus of sub-grade reaction of 150mm thick DLC sub-base (K kg/cm2/cm)

Elastic modulus of concrete (E kg/cm2) Co-efficient of thermal expansion of concrete (œ) Spacing of contraction joints

The above parameters have to be either assumed or calculated at one point of time during the design process .

CHECK FOR FATIGUE LIFE According to the site conditions and

requirements the following have to be assumed

Trial Thickness Subgrade modulus Design Period Modulus of rupture Cement concrete grade

The fatigue life can be found out from the Table no 6 of IRC 58-2002 of stress ratio v/s fatigue life

Using this data ,Axle load and the expected repetition the fatigue life consumed is found out.

The cumulative Fatigue life consumed is then checked for 1 or less than 1.

CALCULATION OF STRESS EDGE STRESS

In IRC 28-1988 the calculation of load stresses was done as per Westergaard’s equation modified by Teller and sutherland. They have limitations as they do not take into account configuration of the wheels.

Now according to the IRC 58 2002 picket and Rays chart can be used for stress computation in the interior as well as in the edge.

Temperature Stress The stress can be obtained as per the Westergaards analysis

using Bradbury’s coefficient using the following equation : Ste=EαtC/2 where s = temperature stress in edge region

E = modulus of elasticity t = maximum temperature differential during

day b/w top and bottom of the slab α = coefficient of thermal expansion of concrete.

CORNER STRESS The load stress in the corner can be obtained as per

Westergaards analysis modified by kelly And calculated using the following equation

sc = 3P/h2[1-(a*21/2 /l)]1.2

Where

sc = Load stress in the corner P = Wheel Load a = Radius of equivalent circular contact area

RADIUS OF RELATIVE STIFFNESS (L)

It is calculated using the formula

L=[Eh3/12(1-µ2)k]1/4

Where

E = Elastic modulus of concrete k = Effective modulus of sub grade reaction

of 150 mm thick DLC sub base K µ = Poisson’s ratio

Flexural Strength of Concrete As per the IS : 456-2000 the folowing equation is used fcr=.7(fck )1/2

Where

fck = Charecterstick compressive stress of concrete cube N/mm2

fcr = Flexural strength(modulus of rupture) N/mm2

Check for Critical Combination The total of temperature warping stress and the highest

axle load stress is calculated using the above design preocess.

It is then compared with the flexural strength of cement concrete.

Moreover the Corner stress is also compared with the flexural strength of cement concrete.

If both the parameters are less than the given flexural strength the design can be concluded as safe and sound.

EROSION CONSIDERATION In addition to the fatigue cracking due to Axle

loading AASHTO Road Test has indicated the serious consideration of erosion of materials from the bottom of the pavement

The erosion is caused largely by tandem and multi axle vehicles while single axle are mainly responsible for fatigue cracking

The solution is to have a 1.5 m paved shoulder beyond the pavement to prevent erosion.

ANCHOR BEAM & TERMINAL SLAB During extreme season Concrete expands and

results in build up of horizontal thrust on the dirt wall or abutment

To contain this RCC anchor beams are provided in the terminal slab

Therefore the terminal slab has to be reinforced to strengthen it.

DESIGN PROCEDURE IN A BLINK1. Stipulate design value for the various parameters2. Decide types and spacing between the joints3. Select a trial design thickness of pavement4. Compute the repetitions of axle loads of different

magnitudes during the design period5. Calculate the stress due to single and tandem

axle loads and determine the cumulative fatigue damage

6. If the CFD is more than 1 select a higher thickness and repeat the stepss above

7. Compute the temperature stress at the edge and if the sum of the temperature stress and the flexural stress due to high highest wheel load is greater than the modulus of rupture of the concrete select a higher thickness and repeat the steps above.

8. Design the pavement thickness on the basis of corner stress if no dowel bars are provided and there is no load transfer due to lack of aggregate inter-lock.

JOINTS FOR CONCRETE PAVEMENT

INTRODUCTION All concrete, once placed, will contract slightly

during the curing process; this is the primary cause of small surface cracks that appear during the curing process. When set, concrete will expand and/or contract slightly with ambient temperature. It is therefore advisable to incorporate some form of movement joint within larger slabs, particularly those 6m x 6m in plan or larger.

TYPES OF JOINT Expansion joints

Contraction joints

Warping or longitudinal joints

MATERIALS FOR CONCRETE JOINTS

Flexible board(IS:1838):- a fibrous, compressible, flexible board, such as 'Flexcell‘

Dowels:- 400-600mm long, 20-32mm in diameter and manufactured from Grade 250 steel.

Sealants: There are three main types:- a) Hot poured - usually bituminous in origin b) Cold applied - often a two-part polysulphide mix incorporating

resin and curing agent such as Colpor 200 or Thioflex. Usually applied via a mastic gun and smoothed with a putty knife.

c) Pre-formed elastomeric - expensive and, in trade parlance. Need to be squeezed and inserted into a scrupulously clean and well-lubricated perfectly formed joint.

TRANSVERSE JOINTSTransverse Expansion Joints For a transverse expansion joint, the dowel should be de-

bonded to half-length to prevent it 'sticking' to the concrete and thereby limiting free movement. In heavy duty applications, such as roadways, the de-bonded half is sleeved and capped, or sheathed in plastic film, to ensure free movement. Provision must be made to support the dowels and maintain their accurate alignment while the first bay hardens.

TRANSVERSE CONTRACTION JOINTS

With transverse contraction joints, again thedowels are de-bonded to one half.In some cases, the sleeving will extend intothe first bay so that when thecompleted joint is formed, the steel dowel isfully insulated from any water orsalts that may find their way in to the joint.

TRANSVERSE CONSTRUCTION JOINTSTransverse construction joints are placed whenever placing of concrete issuspended for more than 30 minutes.

If the construction joint is located at the site of expansion joint, regularexpansion joint shall be provided; if at the site of a contraction joint orotherwise, the construction joint shall be of butt type with dowels. The jointshould be placed only in the middle third of the specified contraction jointinterval.

Procedure of construction of butt joint is given in clause 8.4 IRC:15-2002and details in Appendix-B of IRC:15-2002

LONGITUDINAL JOINTSPlain butt type joints

Plain butt type joints are not particularly common between two new concrete bays, b ut they are occasionally encountered as the joint between a new concrete slab and previously concreted slab or another fixed feature, such as a wall, as the wall (or other feature) is not capable of being dowelled

MACHINE CUT JOINTSMachine cut joints are the simplest of

joints in that they are basically a break in the concrete created to allow the natural shrinkage of concrete (because of curing and/or temperature change) to take place without generating crack inducing tensile forces within the slab. Longituinal joints becomes neccessary to relieve warping stresses when the pavement width exceeds 4.5 m.

DOWEL BARS Dowel bars are built as an integral part of transverse joints. They are

usually mild steel round bars of short length, whose half length is bounded into concrete on one side of the joint and its other half length is prevented from bonding with concrete.

They are so designed that they will be capable of transferring 40-45% of gross controlling wheel load to the adjacent slab.

The design procedure for dowels is indicated in IRC:58 “Guidelines for the Fesign of Rigid Pavements for Highways”.

TIE BARS Tie bars are used across the joints of concrete pavements wherever it is

necessary or desirable to ensure firm contact between slab faces or to prevent abutting slabs from separating.

Tie bars are not designed to act as load transfer devices. Tie bars are designed to withstand tensile stresses only. The maximum tension in the tie bars across any joint is equal to the force required to overcome friction between pavement and sub-grade.

The design procedure and details of tie bars for longitudinal joint of two lane rigid pavements are given in supplementary notes N-5,IRC:15-2002

GIDC PANDESARA LOCATION

SURVEYING WORK

ACTUAL RIGID PAVEMENT DESIGN.(GIDC PANDESARA) The following design parameters are considered for

calculating the thickness of concrete slab.

Grade of concrete: M40

Design wheel load: 8000 kg

Effective modulus of subgrade reaction K : 13.8 kg/cm3/cm2

Elastic modulus of concrete E : 3 x 105 kg/cm2

Poission’s ratio : 0.15 Thermal co-efficient : 10 x 10-6 per 0C Tyre pressure - q :8 kg/ cm2

Rate of traffic growth – r : 8.0 % Spacing of contraction joint – L : 4.5 m Width of slab B : 3.5 m Design period - n : 30 years Thickness of CC slab : 275 mm (Assumed)

FLEXURAL STRENGTH OF CEMENT CONCRETE – GRADE – M40

Where fcr = Flexural strength (modulus rupture), N/mm2

fck= Characteristic compressive cube strength of concrete

= 400 kg/cm2 = 40.77 N/mm2

ckcr ff 7.0

77.407.0crf

= 43.85 kg/cm2

RADIUS OF RELATIVE STIFFNESS: L

Where, Elastic modulus of concrete-

E : 3 x 105 kg / cm2

Effective modulus of sub-grade reaction of the 150 mm thick DLC sub-base- K : 13.8 kg/cm2/cm

Poission’s Ratio- μ : 0.15

4/1

2

3

)1(12

k

Ehl

4/1

2

35

8.13)15.01(12)5.27(103

l

79.78l

RADIUS OF LOAD CONTACT AREA ASSUMING CIRCULAR IMPRINT = A

P = Design wheel load = 10000 kg

s = C/C distance between two tyres = 31 cm

q = Tyre press = 8.0 kg/cm2

5.05.0

5227.08521.0

q

PsqPa

5.05.0

85227.010000

14.331

14.3880008521.0

a

51.26a cm

RADIUS OF EQUIVALENT DISTRIBUTION OF PRESSURE I.E. EQUIVALENT RADIUS OF RESISTING SECTION= B

hhab 675.021

226.1

5.27675.021

2)5.27(2)51.26(6.1 b

20.25b

5 LOAD STRESSES IN THE CRITICAL EDGE REGION

]4048.0blog 4)b/1(log 4)[54.01(P/h 529.0 10102

]4048.020.5210log 4)20.52/79.78(10log 4)[15.054.01(2)2.7(2

00080.529

94.17

Where = load stress in the edge region, kg/cm2 P = Design wheel load, kg half of the single axle load One-fourth of the tandem axle load h = pavement thickness, cm µ = poisson’s ratio for concrete E = modulus of elasticity of concrete, kg/cm2 K = modulus of subgrade reaction, kg/cm3 l = radius of relative stiffness, cm b = radius of equivalent distribution of pressure = a for

a/h > 1.724 a = radius of load contact area, assumed circular, cm

CHECK FOR TEMPERATURE (WARPING) STRESSES

Length of Slab = L = 450 cm Width of Slab = B = 350 cm Radius of relative stiffness =

l = 78.79 L/l = 450/78.79=5.71 B/l = 350/78.79=4.44 Bradbury’s Co-efficient C =

0.86 Modulus of Elasticity of

Concrete = 3 x105 kg/cm2

Temperature differential =15.8 0C

Co-efficient of Thermal Expansion = 10x 10-6 per 0C

2 tCEEdge Warping Stress =

28.15101010386.0 65

= 20.38 kg/cm2

=

CHECK FOR CRITICAL COMBINATION

Total of temperature warping stress and the highest axle load stress is therefore:

17.94 + 20.38 = 38.32 kg/cm2

Which is less than 43.85 kg/cm2 (the flexural strength of C.C.). The assumed thickness of pavement slab of 27.5 cm of M-40 grade is safe under combined action of wheel load stress and temperature stress at pavement edge.

CHECK FOR CORNER STRESS The design wheel load P = 10000

kg Thickness of pavement slab h =

27.5 cm Radius of relative stiffness l =

78.79 Radius of area of contact of wheel

= a

Corner Load stress

2.1

2

213la

hP

2.1

2 79.78267.281

)5.27(100003

= 21.818 kg/cm2

CHECK FOR CORNER STRESS

= 11.20 kg/cm2

Therefore critical combination: - 21.818 + 11.20 =

33.02 kg/cm2

Corner Warping Stress laEet

)1(3

79.7867.28

)15.01(38.151010103 65

=

DESIGN OF DOWEL BARS

Design Parameters

Design wheel load = 8000 kg Percentage of load transfer = 40 % Pavement slab thickness h = 27.5 cm Joint width z = 2.0 cm Radius of relative stiffness = 78.79 cm

PERMISSIBLE BEARING STRESS IN CONCRETE

b = Diameter of Dowel Bar

= 3.2 cm Assumed

525.9)16.10( ck

bfb

F

525.9400)2.316.10(

bF

= 292.28 kg/cm2

TOTAL LOAD TRANSFER BY DOWEL BAR ASSEMBLY Assumed spacing between the dowel bars = 25 cm c/c First dowel bar is place at a distance of 15 cm from the pavement

edge Assumed length of the dowel bar = 50 cm No. of dowel bar participating in load transfer

Spacingl

1

2579.781 = 3.15 Nos. say 4 Nos.

TOTAL LOAD TRANSFERRED BY DOWEL BAR SYSTEM

= (1+0.682+0.365+0.048) Pt

= 2.095 Pt

Load carried by the outer dowel bar, Pt

2.095 Pt =8000 x 0.4 Pt = (8000 x 0.4) / 2.095 =1527.44 kg

tP

79.78

7579.7879.78

5079.7879.78

2579.781

CHECK FOR BEARING STRESS

Moment of Inertia of Dowel 64

4b

64)2.3(14.3 4

= 5.147 cm4

CHECK FOR BEARING STRESS

EIZKPt

34)2)((

147.5102)238.0(4))2238.0(2)(4150044.1527(

63

Bearing stress in dowel bar =

= 282.74 kg/cm2 which is less the 292.8 kg/cm2

DESIGN OF TIE BARS Design Parameters

Pavement slab thickness = 27.5 cm Lane width b = 3.50 m Co-efficient of friction f = 1.5 Density of concrete = 2400 kg/m3

Allowable tensite stress in deformed bars = 2000 Allowable bond stress for deformed bars = 24.6

kg/cm2

Diameter of deformed bar – assumed = 12 mm

SPACING AND LENGTH OF THE DEFORMED TIE BAR

Assuming a diameter of tie bar of 12 mm, the cross section area

A=1.13 cm2

Spacing of Tie bar is A/As = 51.08 cm Say 51 cm c/c Provide spacing 50 cm C/C

sbfwAS

20002400275.05.150.3

SA

= 1.7325 cm2/m

SUMMARY OF PAVEMENT DESIGN

Thickness of pavement slab = 275 mm Pavement Quality concrete grade = M40 Size of Panel = 4.5 m x 3.50 m

Length = 450 cm Width = 350 cm

Dowel Bar Details Diameter of bar = 32 mm Spacing = 250 mm c/c Length = 500 cm

Tie bar details Diameter of deformed bar = 12 mm Spacing of deformed bar = 50 cm c/c Length of deformed bar = 65 cm

Pavement Composition Top 300 mm natural subgrade soil is to be

replaced by CNS Soil / Stabilized soil with Fly Ash and Lime

150 mm thick compacted Granular Sub-base (GSB)

150 mm thick Dry Lean Concrete (DLC)

125 micron minimum thickness of polythene sheet as separation layer over DLC

275 mm thick Pavement Quality Concrete (PQC) Slab-M40

Sub surface drainage :- For Sub-surface drainage, 150 mm thick GSB shall be thickened to 300 mm for a width of 500 mm near shoulder portion throughout the length and drainage outlet shall be given in the form of 150 X 150 mm GSB band for shoulder length of 30.0 m c/c throughout the road length of project.

ESTIMATE FOR RIGID PAVEMENT

SITE CLEARANCE EARTHWORK EARTHWORK IN FILLING PAVEMENT

TOTAL

Rs 63,62,527 Rs 51,70,298 Rs 2,63,47,453

Rs 26,50,89,152

Rs 30,29,69,430

FEXIBLE PAVEMENT

LOAD DISPERSION MECHANISM

FACTORS The factors that affect the thickness design of flexible

pavements are:

Traffic loading Sub-grade soil characteristics.

SUB-GRADE SOIL CHARACTERISTICS

The primary factors are as follows: The general characteristics of the sub-grade soils such as soil

classification, limits, etc. Depth to bed rock. Depth to water table (including perched water table). The compaction that can be attained in the sub-grade and the

adequacy of the existing density in the layers below the zone of compaction requirements.

The CBR that the compacted sub-grade and uncompacted sub-grade will have under local environmental conditions.

The presence of soft layers in the sub-soil. Susceptibility to detrimental frost action.

A sub-grade’s performance generally depends on three of its basic characteristics (all of which are interrelated):

Load bearing capacity: The sub-grade must be able to support loads transmitted from the pavement structure. This load bearing capacity is often affected by degree of compaction, moisture content, and soil type. A sub-grade that can support a high amount of loading without excessive deformation is considered good.

Moisture content: Moisture tends to affect a number of sub-grade properties including load bearing capacity, shrinkage and swelling. Moisture content can be influenced by a number of things such as drainage, groundwater table elevation, infiltration, or pavement porosity (which can be assisted by cracks in the pavement). Generally, excessively wet sub-grades will deform excessively under load.

Shrinkage and/or swelling: Some soils shrink or swell depending upon their moisture content. Shrinkage, swelling and frost heave will tend to deform and crack any pavement type constructed over them

TRAFFICFor estimating design traffic we need:1.Commercial vehicle per day (CVPD)2.Traffic growth rate3.Design life4.Vehicle damage factor (VDF)5.Distribution of commercial traffic over the

carriageway

CVPD Estimate of initial daily average traffic flow for

any road should normally be based on atleast 7 days, 24 hours classified traffic counts. In case of new roads, traffic estimates can be made on the basis of potential land use and traffic on existing routes in the area.

TRAFFIC GROWTH RATE1. By past trends2. By establishing econometric models, as per IRC:108

“guidelines for traffic prediction on Rural Highways”.

If adequate data is not available, it is recommended that an average growth rate of 7.5% may be adopted.

DESIGN LIFE NH and SH = 15 years Expressways and urban roads = 20 years Other roads = 10-15 years

Very often it is not possible to provide full thickness of pavement right at the time of initial construction. Stage construction techniques should be resorted to in such cases.

VEHICLE DAMAGE FACTOR VDF is a multiplier to convert the number of commercial vehicle of different

axle loads and axle configuration to the number of standard axles per commercial vehicle.

Varies with:1. Vehicle axle configuration2. Axle loading3. Terrain4. Type of road 5. Region to region

The load equivalency factors recommended in the AASHTO guide are given in Annexure-2 IRC:37-2001.

The indicative values of VDF are given in Table-1 (3.3.4.3 IRC:37-2001)

DISTRIBUTION OF COMMERCIAL TRAFFIC OVER THE CARRIAGEWAY

Single-lane roads (100%) Two-lane single carriageway roads (75%) Four-lane single carriageway roads (40%) Dual carriageway roads

two-lane = 75%dual three-lane = 60%dual four-lane = 45%

COMPUTATION OF TRAFFIC DESIGN

N = The number of standard axles to be catered for in the design in terms of msa.

A = Initial traffic in the year of completion of cinstruction in terms of the number of commercial vehicles per day.

D = Lane distribution factor F = Vehicle damage factor n = Design life in years r = Annual growth rate of commercial vehicles

P = Number od commercial vehicles as per last count.x = Number of years between the last count and the year of

completion of construction

SUBGRADE The subgrade whether in cut or fill should be well

compacted to utilize its full strength and to economize thereby on overall thickness of pavement required.

The subgrade strength for design is assessed in terms of CBR of the subgrade soil in both fill and cut sections at the most critical moisture condition likely to occur in-situ.

The test procedure for determining the CBR value is describes in IS:2720 (Part 16).

PAVEMENT THICKNESS Pavement thickness charts are given in Fig. 1

and Fig. 2 in IRC:37-2001, according to the msa and CBR value

OUR DESIGN OF URBAN SURAT ROADS As a part of our project, we have tried to design the urban roads in

Surat. After initial inspection, the roads appeared to have depression /

settlement / distress and disintegration of bituminous surfacing occurred specifically during post-monsoon season is due the failure of sub-base as subgrade soil is black-cotton and curst has performed far below due to very poor subgrade soil in its soaked condition.

It was therefore decided to study thoroughly the property of subgrade soils from the samples collected from 07 different locations covering almost all zones namely Dindoli, Godadra, Jiyav, Budiya, Unn, Vesu, and Bharthana.

The SMC is undertaking the project at 4 different levels, depending on the width of the road. We are taking for 2 cases, where width is lesser than 12m and width is between 12m and 24m.

Testing was done at Unique Engineering Testing and Advisory Services of Udhana, Surat

The following tests were carried out- Grain size analysis Atterburg’s limit IS soil classification Modified proctor density test Soaked CBR test.

RESULT SUMMARY The test results of soil shows that it is black cotton soil

having I.S. Soil Classification ‘CH’ except for Budiya, Unn and Vesu, where soil is classified as ‘CI’

The Grain Size Analysis indicates that soil is consisting of 83 % to 94 % clay + silt and 3 to 15 % sand and 0 to 2 % gravel.

As per IS 1458, the soil classification is ‘CH’ for majority of locations with L.L. more than 50 % and PI varies from 25 to 29 % MDD is almost 1.81 to 1.93 % with OMC varies from 13 to 18 %.

The minimum strength of subgrade soil in soaked condition in terms of CBR is 3.4 %.

TRAFFIC TRENDS IN SURAT

Sr. No

Road Approximately width of Road (m)

Approximately Lane

Maximum no- CV Passed / Day

Calculated msa

1. Sumul Dairy Road- Station to katargam

10 2 (Dual Carriage)

532 7.21

1. Sumul Dairy Road- Katargam to Station


593 8.04

1. Ashwani Kumar Road – Visamo to Station


929 29

1. Ashwani Kumar Road – Staion to Visamo


1228

1. Old Bhatar Road – Albee to Bhatar cross

18 4 (Single Carriage)

623 10.78

1. Old Bhatar Road – Bhatar Cross to Albee

18 4 (Single Carriage)

868

1. Shanti Nagar Road – South Zone Office to Shanti Nagar


588 7.97

1. Shanti Nagar Road – Shanti Nagar to South Zone office


391 5.3

1. Kshetrapar Road – Majura Gate to shankheswar complex


798 8.65

1. Kshetrapar Road – Shankheswar Complex to Majura Gate


807 8.75

1. Krishana Nagar Nar Road – Gujarat Gas Circle to Rander Road


860 9.33

1. Krishna Nagar Nar – Road Rander to Gujarat Gas Circle


849 9.21

DESIGN TRAFFICIt is based on 2 factors-

Initial traffic-

Growth rate- assume 8%

Sr. No Name of roads Commercial Vehicles per day as on 2003 in both direction = P

(i) Residential Street – Width upto 12.0 m

900

(ii) Collector Roads – Width from 12.0 m to 24.0 m

1200

PAVEMENT DESIGN LIFE Assume a design life of 15 years

VEHICLE DAMAGE FACTOR

S.no. Name of road VDF1 Residential Street –

Width upto 12.0 m3.5

2 Collector Roads – Width from 12.0 m to 24.0 m

4.5

LANE DISTRIBUTION FACTOR

Sr. No Name of roads Lane Distribution Factor = D

(i) Residential Street – Width upto 12.0 M 0.75 of Traffic Volume in

both Direction

(i) Collector Roads – Width from 12.0 M to 24.0 M 0.40 of Traffic Volume in

both Direction

CALCULATIONS (A) Initial traffic in the year of Completion of Construction

in terms of CVPD is as under : (i) All Residential Streets having width up to 12.0 m A = P (1 +r)n

= 900 (1 +0.06)10 = 1611.76 say 1500.00(ii) All Collector Roads having width from 12.0 m to 24.0 m A = P (1 +r)n

= 1200 (1 +0.06)10 = 2149.01 say 2000.00

5.375.0150008.0

]1)08.0[(365 15

l

N

The cumulative number of standard axles to be catered for in the design in terms of msa is as under : (i) All Residential Streets having width upto 12.0 m

= say 39.0 msa

5.440.0200008.0

]1)08.0[(365 15

l

N

(ii)All Collector Roads having width from 12.0 m to 24.0 m

= say 35 msa

SPECIAL PROVISIONS Buffer layer- There is a definite gain in placing the

pavement on a non-expansive cohesive soil cushion of 0.6-1.0 m thickness.

It prevents ingress of water in the underlying expansive soil layer, counteracts swelling

even if the underlying expansive soil heaves, the movement will be more uniform and consequently more tolerable.

Blanket course- A blanket course of atleast 225 to 300 mm thickness and composed of coarse / medium sand or non-plastic moorum having PI less than five should be provided on the expansive soil subgrade as a sub-base

This is done to serve as an intrusion barrier. We have taken 300 mm blanket course

FINAL DESIGN OF ROADS OF WIDTH UPTO 12M (RESIDENTIAL ROADS) The input design data for flexible pavement are given

below:

(i)Soaked CBR = 3.0% considering capping layer of coarse sand for top 300 mm of

subgrade soil(ii) Design Traffic in m.s.a. = 39.0(iii) Design Period = 15 years (iv) Average annual Rainfall > 1500 mmAs per guidelines for the design of Flexible Pavements given in

IRC: 37-2001, Figure no-1, the total thickness of pavement curst for the above input design data is 900 mm.

(i) Sub-base Course = 380 mm (ii) Base Course = 250 mm(iii) Bituminous Surfacing = 190 mm Total = 820 mm

Sr.

No

Brief Description of pavement Composition Thickness

1 Semi-Dense Bituminous Concrete (Compacted) - SDBC

30 mm

2 Bituminous Macadam (Compacted) - BM

60 mm

3 Built-up Spray Grout (Compacted)- BUSG

75 mm

4 Water Bound Macadam (WBM)

150 mm

5 Granular Sub-base (Compacted) - GSB

300 mm

6 Lime – Fly Ash Stabilized subgrade soil (Compacted)

150 mm

7 Total Thickness of Crust including stabilized subgrade soil

765 mm

8 Prime Coat

9 Tack Coat

10 Asphalt Painting

Results

Schematic diagram of 12m wide roads

FINAL DESIGN OF COLLECTOR ROADS HAVING WIDTH OF 12M TO 24M Design of crust thickness-The input design data for flexible pavement are given below:

(i)Soaked CBR = 3.0% considering capping layer of coarse sand for top 300 mm

of subgrade soil(ii) Design Traffic in msa = 35.0(iii) Design Period = 15 years (iv) Average annual Rainfall > 1500 mm

As per guidelines for the design of Flexible Pavements given in IRC:37-2001, Figure no-1, the total thickness of pavement curst for the above input design data is 900 mm. The composition of pavement structure as per guidelines are given below: (i) Sub-base Course = 380 mm (ii) Base Course = 250 mm(iii) Bituminous Surfacing = 190 mm ---------- Total = 820 mm

RESULTSSr. No Brief Description of pavement Composition Thickness

1 Semi-Dense Bituminous Concrete (Compacted) - SDBC

40 mm

2 Bituminous Macadam (Compacted) - BM

80 mm

3 Built-up Spray Grout (Compacted)- BUSG

75 mm

4 Wet Mix Macadam (Compacted) - WMM

200 mm

5 Granular Sub-base (Compacted) - GSB

300 mm

6 Lime – Fly Ash Stabilized subgrade soil (Compacted)

200 mm

7 Total Thickness of Crust including stabilized subgrade soil

895 mm

8 Prime Coat

9 Tack Coat

10 Asphalt Painting

SCHEMATIC DIAGRAM OF ARTERIAL ROADS

CONCLUSION Our project consists of theoretical study as well

as industrial applications Our biggest concern was studying the literature

for the project as it is not covered in the course Both of our designs for the pavements are in

accordance with the IRC guidelines and are industrially accepted.

Thus, our project is complete

THANK YOU

pavement design

Documents

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design of pavementssubmitted

tyre pressure irc

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subgrade soils

uncompacted subgrade

concrete of concrete

tonnestridem axle