Summar tranning report of pwd

A REPORT ONSUMMER TRAINING AT

CHETAK ENTERPRISES Ltd.

Prepared By:

Dharm Raj Patel

1212700042

B.Tech Civil Engineering, 4th year,

IIMT Engineering College, Meerut

ACKNOWLEDGEMENT I take immense pleasure in thanking Md. Ishakh of chetak

enterprises for having permitted me to carry out this practical summer to all those who have shaped and enriched my understanding by sharing their insights and experience with me.

I wish to express my deepest sense of gratitude to my internal Guide, Mr. Vindya pratap of chetak enterprises for their training.

TABLE OF CONTENTSTopic Page No.

Introduction 4

IRC Method of Flexible Design Pavement 11

Design Procedure 17

Construction procedure 22

Conclusion 32

INTRODUCTION

Public Works Department Uttar Pradesh is the premier agency of Government of Uttar Pradesh engaged in planning, designing, construction and maintenance of Government assets in the field of built environment and infrastructure development. Assets in built environment include Hospitals, Schools, Colleges, Technical Institutes, Police Buildings, Prisons, Courts etc; assets in infrastructure development include Roads, Bridges, Flyovers, Footpaths, and Subways etc. PWD Uttar Pradesh also sustains and preserves these assets through a well developed system of maintenance which includes amongst others specialized services like rehabilitation works, roads signage and aesthetic treatments like interiors, monument lighting, landscaping etc

ROAD AND ITS TYPE

Roadways in India are like the thread binding the topographical variations in India. The road network of India has proven its efficiency by providing its infrastructural contribution to the growth of Indian economy. India is a land of diversities and the Indian roads act as a national integration force providing the necessary adhesive for bringing the people from all corners together as easily as possible.

The road transport system of India is one of the widespread network. It spans the entire nation in the form of small pagdandis, ring roads, flyovers, highways, expressways, and freeways. The roadways travel has developed into an infrastructure strength that has given the Indian economy the necessary backbone support.

The road network in India especially in the more remote areas helps in the development of these regions by connecting them to nearby cities making the modern day facilities more accessible to them. Roadways of India has helped enhance the productivity of certain areas and contributed to the evolving of a more competitive infrastructure and economy on the world level

Road transport in India or roadways transport contributes to 60% freight or cargo transport and 80%passenger transport of India. These include roadways buses, roadways express services, transport both public and commercial systems and others.

Special buses of Indian roadways equipped with automated speed enforcement systems are gaining popularity and also the attention of various state governments awing to the rising cases of road accidents due to uncontrolled speeds of roadways buses. Various websites provide Indian road maps that give you the exact India road distances and some sites also provide India road distance calculator that gives you a clearer idea of the distance you would be travelling. Road transportation in India is a state government entity with individual roadways enquiry systems per state.

The various modes of transportation in India and the road infrastructure in India are under the management and administration of the respective state or union territory governments. The exception is the national highways that is the Central Government responsibility and managed by the National Highways Authority of India.

Roads are useful in various transport means like that goods, passengers to their destination. There are various types of roads. The roads are classified on various aspects. They are as following.

A.ON THE BASIS OF MATERIAL USED:-1.BITUMINOUS ROADS

2.R.C.C. ROADS

B.ACCORDING TO IRC:-1.NATIONAL HIGHWAY

2.STATE HIGHWAY.

3.MAJOR DISTRICT ROADS.

4.OTHER DISTRICT ROADS.

5.VILLAGE ROADS.

C.ON THE BASIS OF SEASON:-1. ALL WEATHER ROADS.

2. FAIR WEATHER ROADS.

D.ON THE BASIS OF ROAD PAVEMENT:-1. PAVED ROADS.

2. UNPAVED ROADS.

E.ON THE BASIS OF PAVEMENT SURFACING:-1. SURFACE ROADS.

2. UNSURFACED ROADS.

(i)UNSURFACED ROAD (ii) SURFACED ROAD

All weather roads are those which are negotiable during all

weather, except at major river crossings while roads on which interruption is permitted during monsoons are called fair weather roads.

Paved roads are provided with a hard pavement course of atleast W.B.M. layer and if it is not so it is called as unpaved road. Ex. earth road or gravel roads.

Surface roads are provided with bituminous or cement concrete surfacing if it is not so it is called as unsurfaced roads.

National highway are main highway running the length and breadth of India, connecting major ports, foreign highways, capitals of large states and large industrial and tourist centers including roads required for strategic movements for the defense of India.

State highways are arterial roads of a state, connecting up with the national highway of adjacent state, district headquarters and important cities within the state and serving as the main arteries for traffic to and from district roads. The national highway and state highway have the same design speed and geometric design specifications.

Major district roads are important roads within in a district serving areas of production and markets and connecting those with each other or with each other or with the main highways of a district. The MDR has lower speed and geometric design specifications than NH/SH.

Other district roads are roads serving rural areas of production and providing them with outlet to market centers, taluk head quarters, block development head quarters or other main roads. These are lower design specifications than MDR.

Village roads are roads connecting villages with each other to the nearest road of higher category. It was specified that these village roads should be in essence farm tracks, but it was desired that the prevalent practice of leaving such tracks to develop and maintain by themselves should be replaced by a plan for a design and regulated system.

The responsibility of construction and maintenance of national highways was decided to be with central government; it was stated that “Centre should select the national highways and trails, accord priorities and pay for all construction and maintenance.”

FLEXIBLE PAVEMENT

Flexible pavements are those, which on the whole have low or negligible flexural strength and are rather flexible in their structural action under the loads. The flexible pavement layers reflect the deformation of the lower layer on to the surface of layer. Thus if the lower layer of the pavement in undulated, the flexible pavement surface also gets undulated.

The flexible pavement layers transmit the vertical or compressive stresses to the lower layers by grain to grain transfer through the points of contact in the granular structure. A well compacted granular structure consisting of strong graded aggregate can transfer the compressive stresses through the wider area and thus form a good flexible pavement layer. The loads spreading ability of this layer therefore depends on the type of materials and the mix design factors. Bituminous concrete is one of the best flexible pavement layer materials. Other materials which fall under this category are, all granular materials with or without bituminous binder, granular base sub base course materials like the water bound macadam, crushed aggregate, gravel, soil aggregate mixes etc.

Flexible pavement may be constructed in a number of layer and the top layer to be strongest as the highest compressive strength are to be sustained by this layer, in addition to wear and

tear due to traffic. Each of the flexible pavement layers above the subgrade, sub base, base course and the surface course may consist of one or more number of layers of the same or slightly different materials and specifications. Flexible pavements are commonly designed using empirical design charts or equations taking into account some of the design factors.

PAVEMENT COMPOSITION

SUB-BASE:-

Sub-base materials comprise natural sand, gravel, laterite, brick metal, crushed stone or combinations thereof meeting the prescribed grading and physical requirements. The sub-base material should have a minimum CBR of 20 % and 30 % for traffic upto 2 msa and traffic exceeding 2 msa respectively. Sub-base usually consist of granular or WBM and the thickness should not be less than 150 mm for design traffic less than 10 msa and 200 mm for design traffic of 1:0 msa and above.

BASE:-

The recommended designs are for unbounded granular bases which comprise conventional water bound macadam (WBM) or wet mix macadam (WMM) or equivalent conforming to MOST specifications. The materials should be of good quality with minimum thickness of 225 mm for traffic up to 2 msa 150 mm for traffic exceeding 2 msa.

BITUMINOUS SURFACING:-

The surfacing consists of a wearing course or a binder course plus wearing course. The most commonly used wearing courses are surface dressing, open graded premix carpet, mix seal surfacing, semi-dense bituminous concrete and bituminous concrete. For binder course,

MOST specifies, it is desirable to use bituminous macadam(BM) for traffic upto o 5 msa and dense bituminous macadam (DBM) for traffic more than 5 msa.

IRC METHOD OF DESIGN OFFLEXIBLEPAVEMENTS

Flexible pavements are so named because the total pavement structure deflects, or flexes, under loading. A flexible pavement structure is typically composed of several layers of materials. Each layer receives loads from the above layer, spreads them out, and passes on these loads to the next layer below. Thus the stresses will be reduced, which are maximum at the top layer and minimum on the top of subgrade. In order to take maximum advantage of this property, layers are usually arranged in the order of descending load bearing capacity with the highest load bearing capacity material (and most expensive) on the top and the lowest load bearing capacity material (and least expensive) on the bottom.

OVERVIEW:-Indian roads congress has specified the design procedures for flexible pavements based on CBR values. The Pavement designs given in the previous edition IRC:37-1984 were applicable to design traffic upto only 30 million standard axles (msa). The earlier code is empirical in nature which has limitations regarding applicability and extrapolation. This guideline follows analytical designs and developed new set of designs up to 150 msa.

SCOPE:-These guidelines will apply to design of flexible pavements for Expressway, National Highways, State Highways, Major District Roads, and other categories of roads. Flexible pavements are considered to include the pavements which have bituminous surfacing and granular base and sub-base courses conforming to IRC/ MOST standards. These guidelines apply to new pavements.

The flexible pavements has been modeled as a three layer structure and stresses and strains at critical locations have been computed using the linear elastic model. To give proper consideration to the aspects of performance, the following three types of pavement distress resulting from repeated (cyclic) application of traffic loads are considered:

1. Vertical compressive strain at the top of the sub-grade which can cause sub-grade deformation resulting in permanent deformation at the pavement surface.

2. Horizontal tensile strain or stress at the bottom of the bituminous layer which can cause fracture of the bituminous layer.

3. Pavement deformation within the bituminous layer.

While the permanent deformation within the bituminous layer can be controlled by meeting the mix design requirements, thickness of granular and bituminous layers are selected using the analytical design approach so that strains at the critical points are within the allowable

limits. For calculating tensile strains at the bottom of the bituminous layer, the stiffness of dense bituminous macadam (DBM) layer with 60/70 bitumen has been used in the analysis.

DESIGN PROCEDURE

Based on the performance of existing designs and using analytical approach, simple design charts and a catalogue of pavement designs are added in the code. The pavement designs are given for subgrade CBR values ranging from 2% to 10% and design traffic ranging from 1 msa to 150 msa for an average annual pavement temperature of 35 C. The later thicknesses obtained from the analysis have been slightly modified to adapt the designs to stage construction. Using the following simple input parameters, appropriate designs could be chosen for the given traffic and soil strength:

_ Design traffic in terms of cumulative number of standard axles; and

_ CBR value of subgrade.

DESIGN TRAFFIC:-The method considers traffic in terms of the cumulative number of standard axles (8160 kg) to be carried by the pavement during the design life. This requires the following information:

1. Initial trance in terms of CVPD

2. Traffic growth rate during the design life

3. Design life in number of years

4. Vehicle damage factor (VDF)

5. Distribution of commercial traffic over the carriage way.

INITIAL TRAFFIC:-Initial traffic is determined in terms of commercial vehicles per day (CVPD). For the structural design of the pavement only commercial vehicles are considered assuming laden weight of three tones or more and their axle loading will be considered.

Estimate of the initial daily average traffic flow for any road should normally be based on 7-day 24-hour classified traffic counts (ADT). 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.

TRACK GROWTH RATE:-Track growth rates can be estimated (I) by studying the past trends of track growth, and (ii) by establishing econometric models. If adequate data is not available, it is recommended that an average annual growth rate of 7.5 percent may be adopted.

DESIGN LIFE:-For the purpose of the pavement design, the design life is determined in terms of the cumulative number of standard axles that can be carried before strengthening of the pavement is necessary. It is recommended that pavements for arterial roads like NH, SH should be designed for a life of 15 years, EH and urban roads for 20 years and other categories of roads for 10 to 15 years.

VEHICLE DAMAGE FACTOR:-The vehicle damage factor (VDF) is a multiplier for converting the number of commercial vehicles of different axle loads and axle congurations to the number of standard axle-load repetitions. It is determined as equivalent number of standard axles per commercial vehicle. The VDF varies with the axle configuration, axle loading, terrain, type of road, and from region to region. The axle load equivalency factors are used to convert different axle load repetitions into equivalent standard axle load repetitions. For these equivalency factors refer IRC: 372001. The exact VDF values are arrived after extensive field surveys.

VEHICLE DISTRIBUTION:-A realistic assessment of distribution of commercial by direction and by lane is necessary as it directly affects the total equivalent standard axle load application used in the design. Until reliable data is available, the following distribution may be assumed.

· Single lane roads: Traffic tends to be more channelized on single roads than two lane roads and to allow for this concentration of wheel load repetitions, the design should be based on total number of commercial vehicles in both directions.

· Two-lane single carriageway roads: The design should be based on 75 % of the commercial vehicles in both directions.

· Four-lane single carriageway roads: The design should be based on 40 % of the total number of commercial vehicles in both directions.

· Dual carriageway roads: For the design of dual two-lane carriageway roads should be based on 75 % of the number of commercial vehicles in each direction. For dual three-lane carriageway and dual four-lane carriageway the distribution factor will be 60 % and 45 % respectively.

PAVEMENT THICKNESS DESIGN CHARTS

For the design of pavements to carry traffic in the range of 1 to 10 msa, use chart 1 and for traffic in the range 10to 150 msa, use chart 2 of IRC:37 2001. The design curves relate pavement thickness to the cumulative number of standard axles to be carried over the design life for different sub-grade CBR values ranging from 2 % to 10%. The design charts will give the total thickness of the pavement for the above inputs. The total thickness consists of granular sub-base, granular base and bituminous surfacing. The individual layers are designed based on the recommendations given below and the subsequent tables.

SUMMARY:-The design procedure given by IRC makes use of the CBR value, million standard axle concept, and vehicle damage factor. Traffic distribution along the lanes are taken into account. The design is meant for design traffic which is arrived at using a growth rate.

The method of design of flexible pavement is covered into two parts namely, new pavements, and widening and strengthening of existing pavements. New pavements shall be designed in accordance with the method prescribed in IRC 37:2001.

ENGINEERING SURVEYS

The stages of engineering surveys are:-

1. Map study

2. Reconnaissance

3. Preliminary surveys.

4. Detailed surveys.

MAP STUDY:-If the topographic map of the area is available, it is possible to suggest the likely routes of the road. In India topographic maps are available from the survey of India, with 15 or 30 meter contour intervals. The main feature like rivers, hills, valleys etc. are also shown on these maps. By careful study of such maps, it is possible to have an idea of several possible alternate routes so that further details of these maps may be studied later at the site. The probable alignment can be located on the map from the following details available on the map.

1. Alignment avoiding valleys, ponds or lakes.2. When the road has to cross a row of hills, possibility of crossing through a mountain

pass.3. Approximate location of bridge site for crossing rivers, avoiding bend of river ,if any.

RECONNAISSANCE:-The second stage of survey for highway location is the reconnaissance to examine the general character of the area for deciding the most feasible routes for detailed study. Some of the details to be collected during reconnaissance are given below:

1. Valleys, ponds, lakes, marshy lands, hills, permanent structure and other obstructions along the route which are not available on the map.

2. Approximate values of gradient, length of gradient, and radius of curves of alternate alignments.

3. Number and type of cross drainage structures, maximum flood levels and natural ground water level along the probable routes.

4. Soil type along the routes from field identifications tests and observation of geological features.

5. Source of construction materials, water and location of stone quarries.

A rapid reconnaissance of the area, especially when it is vast and the terrain is difficult, may be done by aerial survey.From the details collected during the reconnaissance, the alignment proposed after study may be done by an aerial survey.

PRELIMINARY SURVEY:-The main objectives are:-1. To survey the various alternate alignments proposed after the reconnaissance and to collect all the necessary physical information and details of topography, drainage and soil.2. To compare the different proposals in view of the requirement of a good alignment.3. To estimate quantity of earth work materials and other construction aspects and to work out the cost of alternate proposals.Topographic detail and soil survey along alternate alignment, consideration of geometric design and other requirement of alignment, preparation of plans and comparison of alternate routes, economic analysis and selection of final alignment. Typical plan, longitudinal section and cross section drawing for the new alignment.

FINAL LOCATION AND DETAILED SURVEY:-The center line of the road finalized on the drawings is to translated on the ground during the location survey. This is done by using theodolite and by staking of the center line. Major and minor control points are established on the ground and center pegs are driven, checking the geometric design requirement.

Survey of the highway construction work for the preparation of the longitudinal and cross sections, computation of earth work quantities and other construction material, and checking detail of geometric design element. All topographical details are noted down and also plotted using conventional signs. Adequate hydrological details are also collected and recorded. The data during the detailed survey should be elaborate and complete for preparing detailed plans, design and estimates of project.

DESIGN

Design details of embankment and cut slopes, foundation of embankments and bridges, and pavement layers.

EARTHWORK:-Excavations or highway cutting and drainage system, construction of embankments. Excavation is the process of cutting or loosening and removing earth including rock from its original position, transporting and dumping it as a fill or spoil bank. The excavation or cutting may be needed in the soil, soft rock or even in the hard rock, before preparing the subgrade. The selection of excavation equipment and the cost analysis is made based on the stiffness of the materials to be excavated.

Earth excavation work may be divided as excavation or cutting, grading and compaction. The depth of the excavation is decided, among the factors, on requirement of vertical profile of the road. The slope is to be provided is governed by the type of soil including stratification and the depth of the cutting. The stability computation may help in arriving at the maximum permissible slope for the complex problems. However highway cuts much flatter slopes are preferred from other considerations including asthetic. Construction of side drains also require excavations along road side.

1. Civil engineering use.2. Military uses.3. Equipment.4. Mass haul planning.

CIVIL ENGINEERING USE:-Typical earthworks include roads, railway beds, causeways, dams, leeves, canals and berms. Other common earthworks are land grading to reconfigure the topography of the site or to stabilize slopes.

MILITARY USE:-In military engineering are more specifically, types of fortification constructed from soil. Although soil is not very strong, it is cheap enough that huge quantities can be used, generating formidable structures. Examples of older earthwork fortifications include moats, sod walls, motte - bailey castles, and hill forts. Modern examples include trenches and berms.

EQUIPMENT:-

Heavy equipment construction is usually used due to the amounts of material to be moved up to millions of cubic meter. Earthwork construction was revolutionized by the development of the scrapper and other earth moving machines such as loader, production trucks, the grader, the bulldozer, the backhoe, and the dragline excavator.

MASS HAUL PLANNING:-Engineers needs to concern themselves with issues of geotechnical engineering such as soil density and strength and with quantity estimation to ensure that soil volumes in the cut match those of fills, while minimizing the distance of movement.

In the past, these calculations were done by hand using a slide rule and with method such as simpson’s rule. Now they can be performed with the computer and specialized software, including optimization on haul cost and not haul distance as haul cost is not proportional to the haul distance.

PAVEMENT CONSTRUCTION

STEP 1:-Preparation of sub base:-Site is cleared and fills and cut are completed. Trench is formed to the required depth of construction, the width of the trench is made equal to that of carriageway. The trench is brought to the desired grade and is compacted.

STEP 2:-Spreading of coarse aggregate:-

The coarse aggregate are spread uniformly to proper profile to even thickness upon the prepared foundation and checked by templates. The course is normally constructed to compacted thickness of 7.5 cm except in the case of cub-base course using coarse aggregate grading no. 1 which is of 10 cm compacted thickness.

STEP 3:-

Rolling:-Compaction is done by three wheeled roller of capacity 6 to 10 ton.Alternatively by an equivalent vibratory roller; the weight of roller depends on the type of aggregate. Rolling is started from edges, the roller is being run forward and backward until the edges are compacted. The run of the roller is then gradually shifted towards the centre line of the road, uniformly overlapping each preceding rear wheel track by one half width. This process is repeated by rolling from either edge towards the centre line until adequate compaction is achieved

STEP 4:-Application of screening:-After the coarse aggregate are rolled adequately, the dry screenings are applied gradually over the surface to fill the interstices in three or more applications. Dry rolling is continued as the screenings are being spread and brooming carried out.

STEP 5:-Sprinkling and grouting:-After the application of screening, the surface is sprinkled with water, swept and rolled. Wet screenings are swept into the voids using hand brooms. Additional screenings are applied and rolled till the coarse aggregate are well bonded and firmly set.

STEP 6:-Bitumen application:-Over the dry and compacted screening binder is applied uniformly applied either with pressure distributer or mechanical hand sprayer.The quantity of bitumen required for this purpose is 50 and 68 kg per 10 square meter for 50 and 75 mm compacted thickness respectively.

STEP 7:-Spreading of key aggregates:-After the application of bitumen, the key aggregates are spread and rolled. The cross profile is again checked.

STEP 8:-Seal coat:-The seal coat is applied if another surfacing course is not constructed immediately and traffic is to be allowed. Either pre-mixed sand-bitumen of surface dressing type of seal coat may be applied. The pavement section is again rolled.

STEP 9:-Finishing:-The constructed pavement is again checked for its cross profile with template and longitudinal profile by straight edge. The maximum permissible undulation on a three meter straight edge is 12 mm and the number of undulation 10 mm and higher values should not exceed 30 in a road length of 300 m. the unevenness indicator developed at the central road research institute , is very useful instrument to locate spots with excessive undulations.

STEP 10:-

Opening to traffic:- Finished surface is opened to traffic if a seal coat or surface dressing has been provided over the penetration macadam after a minimum period of 24 hours.

CONSTRUCTION PROCEDURE FOR SURFACE DRESSING.

STEP 1:-Preparation of existing surface:-The existing surface is prepared to the proper profile and ruts, depressions etc. are rectified before the treatment is done. The surface is made free of dust or loose material. A prime coat is applied if the existing base course has a previous surface such as soil stabilized material.

STEP 2:-Application of binder:-On a prepared surface using a mechanical sprayer, uniform spraying of bituminous binder is done at the specified rate. Care is taken that excessive binder is not applied to the localized areas as this would cause bleeding.

STEP 3:-Application of stone chipping:-After the application of binder, the cover material i.e. stone chipping as per the requirement is spread to cover the surface uniformly.

STEP 4:-Rolling of first or final coat:-The rolling is done with the roller of 6 to 8 tones weight after the cover material is spread. When rolling of one half width up to the centre is completed this way, the rolling is carried out on the half coat is applied then the rolling is done again after the treatment is done for second coat.

STEP 5:-Finishing and opening to traffic:-The surface is checked for longitudinal and cross profile using a straight edge of length 3 meter and variation in surface greater than 6mm are corrected. The road section is opened to traffic after 24 hours.

CONCLUSION

The training at chetak enterprises was a great learning experience. The curriculum was very well scheduled. It gave me an opportunity to learn about various fields in which civil engineers are involved. I also got a decent amount of knowledge of design of flexible pavements and various methods involve in it. I also got decent knowledge of various instruments used in road construction and it’s designing during my training.

It is very important to have knowledge of difference between practical things and theoretical things. At last I would like to express my greatest sense of gratitude to the organization for adding to my knowledge.